A bit on Hydraulics

In a hydraulic system, a number of components are used to convert a power source into hydraulic pressure to do a task not easily achieved with the original power source. An example; say you have only a somewhat small gasoline motor, and want to make a nice portable log splitter. From experience you know that you have to use a wedge shaped object to spread the wood from the end to cause it to split. You know that a 12# maul swung as hard as you can will not always split the wood so you want lots of force to push the wedge into the wood to effect the split. To have the small gas engine do the work you need to take the relative rotational energy at the output shaft and convert that into a linear motion to push the wedge, or some other way of getting that wedge into the wood with great force. So one way is to use a hydraulic cylinder to push the wedge. A straight linear push is what hydraulic cylinders do well. So a simple frame that holds the cylinder on one end and at the other either the wedge or an end stop. In any case the cylinder rod and the fixed end trap the wood between a flat and a wedge and the wood is split. But wait, it it is not yet split because the hydraulic cylinder needs hydraulic fluid, flowing with pressure to move. So you need a pump to make the fluid flow and to take some of the energy from the engine rotating shaft and raise the pressure of the fluid. So now on your frame you make a mount, and bolt the engine down. You then have to somehow couple the shaft from the engine to the pump, so one of several styles of coupling is used and the pump is connected to the engine. You also have to mount the pump either to the engine case or the frame to keep it in place and prevent it just spinning with the shaft. OK so now we have that engine mounted, and the pump mounted, how to get that fluid to the cylinder so it does not just spray around. Tube, pipe and hoses are used. Rather obviously they have to be able to hold the pressure. But wait, we also want to be able to split more then ONE piece of wood, so we have to be able to put oil to both ends of the cylinder as we desire to change the direction of the cylinder, so now we have to add a valve, and more of those tubes, pipes or hoses, again all able to take the full pressure we will see when the wood is strong and the pressure must be high. But what happens when the wood is TOO strong? Since most pumps move a fixed amount of oil for every revolution, if the cylinder stalls, and the fixed amount of oil is moved every revolution of the motor what happens? Since oil is almost non compressible, the pressure will rise till one of several things happens. The wood will split, the coupling between the motor and pump will fail, the frame will fail, the engine will stall or the weakest item will fail and spray oil. SOOO>>> we also need an item called a pressure relief valve that opens to let fluid flow so the pressure stays at or below the safe range. Last but not least a container of some sort is required to hold that oil. Do we need a container to hold the oil? Can't we just take the oil coming from the cylinder as it moves and feed it right back to the pump to have energy added and send it to the other side? Since we have a cylinder with only one rod coming out one end NO. The rod displaces oil so the amount of oil displaced as the cylinder moves in the direction that extends the rod is less then need to fill the side without the rod and vice versa. That tank is often the item given the least thought of the system. The lowly tank has several functions. It must hold the fluid without leaking. It gives the fluid a place to rest, to give foam a chance to float up and dissipate, for particles to settle out and also an important thing - a place to let the heat flow from the oil, through the tank walls and out into the air.

So, the need for a valve to move the cylinder both ways can be easily filled with any of a number of types. Say you don't mind moving a lever back and forth. So you use a "4-way, 2 position directional control valve" this would have 2 positions, and would either put oil to the extend side and connect the other side to tank or vice versa. This has some issues. when the cylinder is stopped at end of stroke, say retracted while you load another log the oil from the pump is going over the relief valve. Since the oil has high energy state IE high pressure, and goes to low pressure as it crosses the valve seat, that energy changes state to heat and noise. The amount of heat is nearly the same as the total energy made by the engine. Not a good choice. So you choose a "3 position, 4 way directional control vale with open center" This valve has 3 lever positions, with the middle position connecting the pressure directly to the tank, and the pump just flows oil, but can't make pressure so much less noise and heat. BUT you have to remember to put the lever in that middle position every time. And if you don't, you get to hear the relief valve scream to remind you. So a better choice is the nifty 3 position, open center, pressure detented 4 way control vale. This one has a little detent that holds the valve in the retract position until the pressure rises and it then pops over to the center position and lets the oil go to tank and all automatically. Most "Log Splitter Valves" are set up this way and even have the relief valve built in to simply the circuit and plumbing. Now that is a very simplified description. There are literally hundreds of possible valve configurations and styles.

There are many basic pump types with the more complex pumps having hundreds of control possibilities. I left out things like filters tank breathers etc. So when you decide to build a hydraulic press, a great deal of the design is done as I went through above. start with the cylinder. Then get it mounted and that leads you to the frame. Now you have to have a way to make the pressure and to control it, and that describes the circuit. Then there is the choice of prime mover. The energy source can be as diverse as a water wheel, a horse on a treadmill to a gas turbine. Not to discourage anyone from designing a press, but rather to understand that there are many many choices, and each choice effects all the other choices. Engineering is a compromise. I will write more bits on each component soon. And if this is all very confusing, you can easily buy a ready made, safe press that will work first try when delivered and you can then charge on and forge more metal.

Written by Jeff Reinhardt

Shop Built Coal Forge


A bit on home built coal forges. I have built quite a few forges over the years, both coal and propane. This bit is about Coal forges. As a scrounger and welder, I like to build my fire pots from steel as it is very easy to weld and to weld well. I like readily available parts and so I usually use a small trailer wheel or the rear wheel from a riding mower. These are all steel and have the almost prefect shape and size. I pick ones that a regular available cast iron forge grate intended for rivet forges just drops in. These grate are available for about $15. They are a perfect drop in like they were made for these steel wheels. A rear riding mower wheel usually has a hub the axle slides into and you can easily cut a round hole to weld a pipe nipple to. Being cheap I weld a side entry to the drop pipe to allow the blower connection. I also weld up a gravity dump. I also usually cut off part of the rim so it is not in the way but it is not really required. I also usually roll a hoop of 1/8" by 1" flat and weld to the rim to make the fire pot that much deeper. These work very well, and the first one I ever built is still in use as a student forge at my shop. Built is 2002. I also usually weld the fire pot into a hole in a scrap of flat plate and using 1/8" x 1" make a rim on that to hold the coal on the table. I just recently used an old stamped Dish antenna as the table and that looks like it will work as well. The biggest lesson here is to scrounge for things that have the shape you really want and adapt that into what you need. I find these wheels on scrap days when people toss out old riding mowers that are not running. You can easily use the front tires and wheels to make you forge mobile as well.

A bit on Electric Motors

A bit on electric motors for the forge shop. When spending hard earned dollars on motors for your blacksmith shop, there are many terms that may confuse. Lets first look at some of the things that kill motors. First and biggest in a metal shop is dust, especially conductive dust. Too much heat is of course bad. Pulling too much power, for too long will overheat and there you are with the too much heat.

So when you are looking for a motor, you see advertised terms like ODP, compressor duty, TEFC. An ODP is open drip proof. Has an internal fan and draws air from your shop and blows it through the inside of your motor. Bad if your shop is dusty, and yours is, don't lie to your self :)

Compressor duty motors are rated for the higher starting loads of a compressor but are almost always an open design and suck air through the internals. TEFC, that is Totally Enclosed Fan Cooled. These have an external fan on the end opposite the shaft that is OUTSIDE the motor case. They blow air over the outside of the motor, cooling it without sucking in all that dust from your shop. (See a bit on respirators for how to not suck that same dust into you) A TEFC motor is usually more expensive then the others. They are usually better built and last longer even in a clean environment. Buy the TEFC motor.

Another way to kill motors is to run them at a voltage that is lower then they need per the nameplate. This is not electrical engineering 101 so in short less volts more amps. Amps are what makes the heat.(Simplified for all the folks that took electrical engineering 101) Si... if you undersize the wires, and run them too far for that size the volts drop and the amps go up and you buy motors more often. If this sounds like mumbo jumbo, it is, hire a mumbo jumbo translator called a licensed electrician. Then you will get a circuit that is to code and will tend to keep you alive and the code inspector smiling.

On motors you often see a nameplate spot for S.F. That is service factor and indicates how hard the motor can be used and expect to get a useful service life. Used hard means things like how much time in any hour you run the motor and at how high a load. Cheap motors often have as low as a 0.85SF. Really good motors will be better then 1 and 1.25SF is very good.

There are many standards for FRAME. A really good concise guide is the motor selection guide in the front of the motor section in the Grainger's catalog.

This just scratches the surface of motors. if you want to know more read that section in the Grainger's. If you find that interesting there is lots more in electrical Mumbo Jumbo translation classes at the local tech school. Enjoy.

A bit on hydraulic presses in the forge

A bit on hydraulic presses in the forge shop. I have been around presses in factories in both forge shops and in many other shops. I personally have designed and built myself presses from about 300# to 100 ton. Came up with concept and did project management on a portable 1000 ton straightening press for 24" x 250# wide flange. I’ve been around commercial forge presses up to 7000 ton. I've done the first aid, and the post accident cleanup and accident reconstructions for too many press accidents. Now that you understand that over the last 40 years I have designed, built, repaired and rebuilt many presses, lets get started.

-First a Harbor Freight press may move some metal but is NOT a forge press. They are ARBOR presses for pushing arbors and bearings and the like.-

So with that out of the way, what are the critical needs in a forging press? The monster has to be safe. that is critical requirement #1. The press needs to be fast for its tonnage. The hydraulics need to be durable and reliable. The frame needs to be rigid. A nice thing is to get these items in a press you can afford.

So what makes a press safe? lets put some items in a list
1. The frame must be able to withstand the load over a useful life.
2. The hydraulics must be as leak free as possible.
The least amount of hose must be used.
The controls must reliably and intuitively work every time.
3 The beast MUST have a big mushroom headed E-stop you can slap when the do-do hits the fan.
The press must sit stable and not be tippy.
The electrical controls need to be to code so YOU the operator do not become the ground path.

That said lets look at why these must be so. If the frame breaks and releases say 16 tons, the hot part may well be fired with 16 tons force and may come at YOU! Also a broken frame means no forging on that machine till fixed.

Leak free hydraulics are a pipe dream. ALL hydraulics leak. The only question is how much. If you use pipe threads in a hydraulic system you are setting your self up for failure. Pipe threads leak. Period. The only question is how much and when. Be aware that in my 40 years in factories the single biggest cause of leaks in hydraulics are hoses. They are a flexible rubber product and the rubber ages and fails. Not if but always when. Can start as a subtle ooze or be be a sudden spraying gusher. Usually starts as an ooze. So when those minimum length hoses show an ooze, replace then.
Pipe threads are a cut into the wall thickness of the pipe and weaken the pipe. Most threaders make really bad rough threads, and so you tape them up with Teflon tape right? Wrong! Teflon tape does not seal threads, it lubricates them and usually bits end up in your oil and clog stuff up. Use pipe dope instead, but always avoid pipe threads if at all possible. SAE style O-ring sealed fittings are better. They too will eventually leak. Write that down before you buy or build a press, it will leak, the only question is when and how much.

Reliable and intuitive controls, keep the beast in control. Nothing worse then the press making an un-commanded move.The intuitive part is so when bad stuff happens you can stop or move the press without thinking.

So what is this mushroom headed E-stop. It is a big switch that you can slap and the pumps STOP. This is great for an un-commanded move, or a sudden leak. I like to have a remote E-stop as well, where when you get a sudden spraying leak, it hits hot metal and now you have a thundering flame thrower, you can slap the remote switch as you EXIT the shop to consider if the remaining fire is fight able. See "A Bit on Fire extinguishers".

The stable thing should be pretty clear, these beasts are HEAVY.

The electrical controls to code, keep you alive and the code inspector happy if he visits.

So with that said what do you want in a press for good performance. You want a press that moves fast at rated tonnage. The dies pull a huge amount of heat out of the billet. A slow press cools the forging before much work can be done. A big press that can overcome the cool forging with tonnage may well tear the forging and make internal cracks. A good press will be fast AND controllable.

Ease of changing dies makes for a versatile press. When you pay as much as these things cost, you want versatile!

A quiet hydraulic system is a blessing. Hydraulics should not SCREAM. When you hear that it usually is a case of flow over the relief valve, which makes lots of noise and heat. If the machine always does this it usually indicates bad design.

A tip, especially when looking at an old press and especially a home brew one is to look for cracked or crazed paint at the welds. Easier to see then a painted over crack. If the press is old and freshly painted look VERY close that may be a hide the cracks paint job. Don't be afraid to ask to scrape the welds to look for cracks. They refuse to allow then take you money elsewhere.

Any hydraulic system should have filtration, and it should be easy to change and the filters easy to obtain.

I will NOT offer design tips as these things are killers if you are not familiar with the entire process. If you have to ask how big a cylinder you need for a certain tonnage, buy a finished press. If you can't figure the size pump and motor needed buy a finished press. If you can't figure the deflection in the structure buy a finished press. Life is too short to spend any of it Dead, injured or in jail.

Of the forge presses on the market currently I like the Coal Iron designs. They have a machine that meets the above.

-Jeff Reinhardt

A bit on oils

There are many base oils for the oils we use every day in our life. Vegetable, petroleum, PAO, silicone, phosphate esters and others. In the shop we use oils for lubes, as hydraulic fluid and to treat metal among other uses.

Lube oils. Most common are petroleum based oil. Once refined the base oil has about a 10-20 ISO viscosity. Since in many cases we want thicker oil a viscosity enhancer is added. The viscosity enhancers are mostly polymers and work well, but do have a life. In highly churned systems, the polymers tend to shear and the oil gets thinner with time. Then there are anti-wear additives and extreme pressure additives. The extreme wear additive is essential in worm gear applications and in heavy load applications like spur gears an bevel gears. The anti-wear package is good for more lightly loaded applications.

Hydraulic oils. These have the functions of a lubricating oil as well as the transmission of pressure. Since these oils tend to be used over a long time they also have anti-oxidation additives and often emulsivity and anti-foam additives.The anti-oxidation additive combines with water in the system and traps same to prevent reaction with the sulfur naturally present in petroleum and prevents acid build up. This additive has a finite amount of water it will capture and then acid buildup starts to occur. Ever smell dark hydraulic oil with a "Burnt" smell? that is the acid after the anti-oxidation additive has been consumed.Burnt oil is pat end of life, replace it quick!

Brake fluids. These are traditionally a PAO base oil and are used in automotive brake systems and some small hydraulic systems. Some newer spec brake oils are silicone oil.

Automatic transmission oils. These oils have all the additives of hydraulic oils as well as an extreme pressure additive and all of the additives are in larger amounts as these are now expected to run the life of the car.

Hydraulic jack oil. Most are simply hydraulic oil, but in those 10,000Psi jacks and porta-powers a very different oil is used. Hydraulic oil made from standard petro base becomes as thick as peanut butter at 10,000psi. You see petroleum becomes more viscous as pressure increases. One exception is Kerosene which has very little viscosity increase with pressure. Most 10,000psi jack oils are very highly refined kerosene based.

Seal compatibility. The seals in our hydraulic systems have to survive a tuff environment. Use the wrong fluid and the seal will shrink and harden or swell and get soft. Has a lot to do with the aniline point of the oil but I digress. In most standard hydraulic systems petroleum based oils are used and in most applications a Nitrile (called Buna N after the German plant that developed it) seal is used. In higher temp apps Viton may be used. Now in a system using phosphate ester oils(Often spec'ed for fire resistance) The Buna N seals will turn to soft sticky mush and be totally destroyed. Add Marvel mystery oil into Buna N seals and same result.
(Most of the Patented Medicine oils sold to Free up or un-stick stuff is hell on regular seals.)

So... have a blower gear box and a hand crank drill press and you need to drip oil on both? Which oil to choose? I would go with ATF! Yes that old red standby Automatic transmission oil. Its cheap and easy to find, safe for regular seals. lubricates all those gears and has a great additive package. It also has a very low change in viscosity due to temp change, so if your shop is 20F you will still be able to crank those antiques.

Written by Jeff Reinhardt

A bit on threads

 Since bolts and nuts were invented, many ways to keep a tight threaded fastener tight have been invented. There are several styles of lock washers and then there is anaerobic locking compound and safety wire, with of course the ultimate redneck locking device, the welder.

First; why do tight threaded fasteners become loose. The primary culprit is vibration. When you consider that a thread is an inclined plane wrapped around a shaft, and the nut is the mirror image, think when vibration moves the nut ever so slightly around the bolt. The inclined plane causes the nut to move away from the load. After many slight moves the nut is loose. 
Another thread loosener is HEAT. if the nut and bolt is heated there will be minor differences in the total expansion of the two due to thickness and perhaps slightly different materials. Same result.

So... how do we keep our threaded fasteners tight? In some low vibration cases simple prevailing torque will do the job. These cases are rare. There are a number of lock washers such as the toothed, the split, and so forth. These dig into the metal of both sides and resist rotation of the items. Ever torque a bolt with a split lock washer and when removed it had gouged out part of the washer and the item bolted? This is how they lock.
Another method of locking threads is a "Staked" nut. These have either been squeezed a bit to make the threads a bit out of round and they resist side to side motion in vibration. Some have a dent in one flat, same method. Some have 3 or so dents on one end of the nut, same method.
Yet another method is an inserted nut. These have a plastic insert that is not threaded and must be force threaded when installed, same method. Both the staked nuts and inserted nuts lose most to nearly all locking effect after removal and re-installation so a new nut should be used at every installation.
Monomer anaerobic locking compounds are a monomer and when they enter the tread space during installation the lack of oxygen and the presence of a bit of trace copper in the steel cause the monomer to cross link into a hard polymer. Most are an acrylic monomer and become something like plexiglass inside the joint. By totally filling the thread tolerance gaps they prevent side to side movement and therefore are very vibration resistant. These do have a critical limit in that temp limits their use. Loctited a bolt with the Red permanent compound? The bolt will break before it turns, but if you heat to say 450F as long as the heat is present no lock and out it comes.

The granddaddy of locking devices is an aerospace device, soft stainless steel wire called Safety Lock Wire. The bolt heads and or nuts have small holes in the corners of the flats and you lace the wire through each bolt, twist it and lace through the next bolt and so forth. Very time consuming but very very effective, just like that blacksmith made locking device, the cotter and later the cotter pin.Cotter pins are very effective when run through a castellated nut, although one has align the slots with the hole and sometimes that is a problem.

Before you laugh, a weld bead along one flat is a very effective locking device and can be easily cut in most cases with a cutoff wheel in a grinder. If nothing else is working this is effective.

Written by Jeff Reinhardt

A bit about the writer!

I am writing these off the top of my head, based on my life in factories, R&D labs, and schooling as well as having been privileged to have worked with many of the great minds of my era in these fields. I have been blessed to have spent about 20 years in R&D lab environments as well as plant engineering, machine design, metallurgy, high pressure technology and welding to scratch the surface. I am proud to be a "Techno-freak" and a Techno-historian. I have worked with or in Maintenance from minor stuff to very heavy machine repair. I am glad to share these bits to spread the knowledge given to me in these environments since about 1970
If I omit something or tell you something that seems wrong, consider that almost everything I write has been proven out in MY experience. Your life experience may be different. I hope that you may gain something from these. I will continue to write these until I have written all I can. I hope that you find something valuable in each one.

Jeff Reinhardt -

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Grease

Greases have been know and used since biblical times or before. One of the first greases was olive oil mixed with lime to make a calcium base grease. Greases can have many base oils and many thickeners. Grease is basically an oil that has been thickened and will thin under shear. Often used in hard to lubricate bearing where oiling is not possible and the oil will not cling, grease must be replaced in the bearing void as it is displaced. Hence grease fittings to force new grease into the voids and the need to repack wheel bearings. Many greases are EP rated with most using a sodium compound or Moly Di sulfide as the agent to keep metal to metal contact from occurring under very heavy load. Some of the thickeners are for very special uses and not often seen, but one should be careful when changing grease base/thickener system as some are not compatible and bad things happen to the bearing when mixed. 
Most grease found in automotive supply houses are a #2 hardness grade. But some machines in the blacksmith shop call for other then a #2 hardness. Some lube points on Little Giants call for a softer grade and using the wrong grade makes the machine fail to run correctly.
LGI number ASTM worked (60 strokes)
penetration at 25 °C
tenths of a millimetre Appearance Consistency food analog
000 445-475 fluid cooking oil
00 400-430 semi-fluid apple sauce
0 355-385 very soft brown mustard
1 310-340 soft tomato paste
2 265-295 "normal" grease peanut butter
3 220-250 firm vegetable shortening
4 175-205 very firm frozen yogurt
5 130-160 hard smooth pate
6 85-115 very hard cheddar cheese

Grade 0 to grade 3 are pretty common in machine tools. The color of grease IE green, blue, red etc is mostly an advertising gimmick.

Written by Jeff Reinhardt

Mig Nozzle Gel

Folks pay good money for the nozzle gel they use to keep the splatter out of their mig guns. As an industrial safety guy I had to read the MSDS, know SDS for every product used in several factories to be able to obtain PPE, dispose of and so on. Much to my surprise, Nozzle gel from several different makers had an ingredients list of something like 99.9% petrolatum. Even though each was a different color they were all Petrolatum. Petrolatum is also sold by the brand name Vaseline. And what my friends was that last crucial ingredient that made each different? 0.1% dye. So, if you want to save a couple of dollars, buy a tub of house brand Vaseline instead of dyed a fancy color vaseline.

Now to an important safety note. YES I SAID SAFETY NOTE, so pay attention all you welders. If you have nozzle spray, or anti-splatter, read the ingredient list on the can. If it says it contains Methylene Chloride, please read the entire sheet below. This chemical has been known as a bad actor for decades but lots is still on shelves and in old cabinets. A much better anti-splatter is spray cooking oil. You can buy the Pam or the house brand, I always suggest the butter flavor since it tastes better :)

Note that in this sheet you will find the following"

Carcinogenicity

The DHHS has determined that methylene chloride may be reasonably anticipated to be a human carcinogen based on adequate evidence in experimental animals.

Written by Jeff Reinhardt

Drilling Stainless

When drilling the 300 series stainless steels one must be aware that they will work harden. They will harden ahead of the cutting lip, and then the drill will skate and become ruined. To drill 300 Stainless, first you need a good quality, sharp drill bit. This pretty much excludes brill bits from HF. Second one needs the right speed and the right feed. Speed is the rate that the cutting lip moves across the metal and the feed is the rate the cutting lip is advanced into the metal usually noted in thousandths/revolution. For the 300 series stainless steel since they work harden, never let the feed relax. If you need to withdraw the bit to clear chips go from full feed and speed to full speed and reverse as instantly as possible.

Another tip is to either avoid center punching or use the lightest center punch as possible as the punch will work harden the metal and make entry of the drill difficult. Some use a 3 sided very slender punch to make a decent mark and make drill entry easier.

A very good field expedient lubricant for low production rate drilling is to use Crisco. Dip the cold bit in start drilling. Re-dip often to keep the lube where it should be. Never ever lube a very hot drill bit when drilling any material as this causes small cracks the cause bit failure.

The Crisco works well for punching stainless sheet cold as well. So if you are using a hand punch or bench punch on stainless sheet try a little Crisco for better punch life and easier punching.

As always Butter flavor is better "Cause it tastes better" 

Written by Jeff Reinhardt

Never-Seize and Lubricants

A bit on "Never-seizing threaded members for high temp use; I was privileged o run the R&D test lab for VOGT for 17 years. Since VOGT made valves for high temp service such as class 2500# steam a high temp never-seize was needed to allow the dis-assembly of bolts and the like after long exposure to temps in the 1200F range. So test articles of the cr-moly steel valve bonnets were made, coated with the never-seizes we had bought , and then torqued to high torques. These threaded joints were about 2.5" diameter with 12 threads per inch. Torqued to about 800 pound/feet. Then off to my 1000f test furnace to back for a couple of weeks. We tested every brand and type of never-seize on the market. There were ONLY 2 that allowed the dis-assembly after this test. One was a tungsten di-sulfide aerosol spray at about $200 a can, and Dow Corning anti-seize 1000. The Dow corning product has an approximate cost today of about $15 a pint can.

While on this subject, we also installed maybe a million 316LSS bolts a year into 316L bodies a year. Again tested every lubricant and anti-seize on the market. Since this was a room temp install, the Dow Corning GN assembly paste was the winner by a country mile and it is available in a lifetime supply of a pint for maybe $25. Life time supply for a blacksmith as a tiny amount of this roughly 70% moly DI-sulfide paste will cover you from head to toe if you keep rubbing. The one thing to be very careful is that this GN paste reduces friction by about 40% over plain grease and therefore it achieves clamp load in the bolt through bolt stretching at about 40% less torque.

Moly DI-sulfide is a natural mined mineral. It has the unique property of having a compression strength of about 350,000psi, yet has a shear strength of near zero. So keeps the loaded metal from ever touching, but shears and acts like slip plates to allow the metal to slide. Since the moly powder is incredibly fine it gets into the cracks and fissure of you hands when you get it on you, and pretty much has to wear out.
Moly grease that has over about 2.5% moly will not pump through grease guns nor should it be used in roiller or ball bearings. 2.5% moly is placed in ball joints on cars at the factory and they last usually for the life of the car. Before moly grease ball joints were a regular lube item and usually had to have fresh grease every 3-5000 miles.

Written by Jeff Reinhardt

Adhesives

A bit on gluing plastic and rubber to metal, especially around Gasoline or metal cutting coolant. Since metal coolants are very active as solvents to most glues, and paints getting stuff like chip flaps and rubber splash guards to stay attached is a tough chore. The one and only one glue that I have found that is truly coolant proof and gasoline proof is called Pliobond. This solvent based adhesive is used usually as a contact type glue to glue rubber, plastic wood and glass to it self and to metal. It is a tan-brown liquid. Comes in metal cans. It comes with different consistencies like Pliobond 10 up to Pliobond 40. Used for things like gluing the rubber de-icer boots to airplane wing leading edges and other very difficult applications. Apply with a disposable brush, have acetone for handy for clean up, and follow the directions. In one machine clamping application using a dense foam as a cushion to prevent marring of the cut parts, the mist coolant for the saw would dissolve the regular contact glue quickly. Once cured the Pliobond 35 is coolant proof. When the foam wears out instead of falling off quickly, the glue line is removed with a 4" twisted knot cup brush as it is still hard and stuck.

To paint items that get exposed to machine coolant, one needs to strip off the old paint, solvent degrease to high cleanliness, and then paint with a catalytic cured paint, NOT a solvent based paint such as Latex or enamel. The solvent cured paints shrink as the solvent evaporates and the micro fissures and pin holes form shrinkage allow the coolant to enter the bond line and float the paint. That is why the paint pretty much slides off as a slimy mess if you use the wrong paint system. When we moved Vogt, the roughly 450 machine tools from the old plant across the river to Indiana, we cleaned and painted every single machine. Used a catalyst cured polyurethane and they were still looking very good 7 years later when the plant closed.

Written by Jeff Reinhardt

Gloves

A bit on gloves; Having about 35 years of factory experience with either safety as a second task or as a primary task, lets discuss gloves. I have worn gloves in factories since 1970. I wore them in the military. I wore them skydiving and as a pilot and jumpmaster. I have worn them as a welder. I have worn them as a chemical response worker and as an asbestos abatement worker. Last but not least I have worn them as both a blacksmith and in industrial forge shops. I have specified them and bought them for big factories where the budget for gloves was $100,000+ per year. That said, I do have a little experience with gloves. I have worn the terrible, rotten, no-good-worthless gloves that some purchasing manager saved "a ton of money on". I have worn good proper fitting gloves.

Most of the myths about gloves being dangerous came from bad glove choice and ill fitting gloves. I will say it is not a myth that one should not wear gloves when running lathes, mills and drill presses. Anything that has that much torque and exposed rotating parts is a glove no go.

Lets talk a bit about choices. I see folks wearing latex exam gloves for oily greasy work. Poor choice as they are attacked quickly by many oils and fail and then fail to protect. Nitrile exam gloves would be the choice there. And you can find this info out by googling glove material chart for chemical compatibility

Lets talk about knit gloves. Many gloves are a type called String Knit. These are knit from yarn somewhat like a knit sweater and have that open weave appearance. While these are a cheaper glove they have no chemical resistance since the chemicals can go straight thru the open weave, they can offer a bit of cut resistance. They, even in a high temp material weave would be a poor choice for forge welding as the flux will go right thru and if above 800F (and it will be well above 800F for welding steel) the Kevlar decomposes and you have a bad burn. Great cut resistance, but no chemical protection. A leather palm on a string knit Kevlar glove is a great cut and abrasion glove. I once worked in a stamping plant where the edges were extremely sharp. The operators wore 3 pair of cotton poly string knit gloves for cut resistance. They tossed then at every break and in so doing used 12 pairs of $0.17/pr gloves a day. The poly melted to them when the got a weld spark, and they were tossing them as they were so cut up after 2 hours the hands were still getting cut. Replaced with a cotton Kevlar "Oven Mitt" that cost just under $3.00 a pair. No more cuts, the cotton content was enough to stop weld sparks before the Kevlar decomposed, and most could get 3 to 5 days wear. Now one hand surgery avoided would have paid for the difference but they lasted so long that they were quickly adopted.Owners were happy as their workers comp cost was lowered and their people were not being hurt. They also liked that several drums of gloves a day were not going to the landfill. The people liked them as they could now work their shift and not be cut or burned and ohh by the way their arms and hands were less tired since they were not trying to grip smooth sheet metal thru 3 layers of fluffy gloves. The cotton content also reduced that hand in a plastic bag feeling of straight Kevlar.

Lets talk about welding gloves. Stick welding calls for Gauntlet type gloves and Chrome tanned leather for its resistance to heat and sparks. Now many wear TIG glove of goatskin or pig skin and they are nicely soft and supple. They also are the wrong material and don't have the insulation to protect from stick welding. They quickly get burn holes.For stick welding, you just spent a ton of money for the equipment and rods, and probably have a nice helmet. Don't buy the cheapest gloves at HF. Buy a name brand, glove that fits and you hands will thank you after a long spell at the welder. TIG gloves are great for that. Light MIG and you tig gloves are only OK. Heavy MIG at bigger wire sizes/amps and you will be wanting those good stick welding gloves.

By now you are wondering what I am going to say about forging gloves. I advocate a glove on the tong or holding hand for cut and abrasion and scale pop protection. I do not advocate a glove on the hammer hand. Increases you grip requirement, and that is usually the last thing you want on your hammer hand. So what kind of glove for that holding hand. I prefer a leather palm glove. You can get a decent Leather palm glove for about $1.25 a pair by the dozen. They have a cotton back that will nicely shed scale and flux. The leather palm protects from cuts and a bit against vibration. and gives a heat protection if CHROME Tanned. This is the one place where I recommend cheap gloves and say get them about one size big so when you goof up and grab something very hot you drop the hot steel and sling the glove off as it is shrinking and getting stiff and you will have at most a mild 1st degree burn. Why the cheap ones? so every time they get stiff from a hot metal contact, or a burn on the canvass back or the stitching fails they can be trashed before you get an injury thru the hole.

And what kind of glove does a skydiver wear? I was a demo jumper for the military and we jumped smoke grenades mounted to our feet. Sometimes the grenade would melt the can seam and spray pyrotechnical smoke(Very HOT!!!) of your foot or leg. If over open country you cut away the mount and the grenade fell away. Over the crowd, no cut away. So you removed the mount from your foot and held it by the straps as you flew the wing parachute over a safe to drop area. I wore rabbit leather gloves with rabbit fur lining to protect against cold at altitude and heat if... They also had to be supple enough to allow pulling the rip cord and cutting away the main parachute in a malfunction. Lot of conflicting requirements. And when I had that run away grenade over a large crowd, I destroyed those gloves. 2 to mild thirdish burns to my hands and fingers, but I could not have held that grenade until clear to drop otherwise. Ruined them and kept my hands. Good trade.

Written by Jeff Reinhardt

Safety Glasses and Face Shields

A bit on Safety glasses and face shields. As an industrial safety guy, I have seen the move from the old horn rimmed with mesh side shields BC safety glasses. The newer styles fit better, are much lighter and provide much better protection due to material changes. In the old days those BC's had glass lens, tempered and 3mm thick instead of the standard 2mm for regular prescription glasses.Those thick glass lenses were really heavy. As the lense and frames progressed to polycarbonate, the impact resistance went way up, the cost and weight went way down. Wrap around styles fit better at the outside edges of the face and provided much better protection there as well as better peripheral vision then the old mesh BC's.

For many years goggles for grinding were terrible things that was much akin to looking thru 2 toliet paper tubes, heavy and nasty. Now there are really nice gasketed safety glasses that keep the swarf out of your eyes. Having tested many, the Pryamex V2G's are the ones that my workers found to be the best. best comfort best anti-fog and I never had a spec in an eye with folks wearing them.

Now a little about face shields. Safety glasses protect the eys. Face sheilds protect? Yep you got it the face. So safety glasses under the sheild are needed for real eye protection. I think all have seen the gory half a grinding wheel in the face photos so I will not go into WHY you wear a face shield, but rather a few tips. If wearing a face shield for impact resistance, pick a polycarbonate window that is impact rated. If you do a lot of torch work a shade 4 or 5 window beats cutting goggles all darn day, and keeps hot splatters from you face.

So... at the end of the day, ready to lift the face shield off and pull the safety glasses and go to the house? More folks get metal in their eyes at this point then one would expect. Your hair and eyebrows hold lots of grit as can your face. The safe way to get the PPE off is to bend at the waist to a 90 degree. Then close eyes and lift off the face shield and safety glasses and then vigorously ruffle the hair and eyebrows and wipe the face. The stand back up, and open your eyes.

Written by Jeff Reinhardt

Respirators

A bit on respirators: This will start with describing the careful introspection and thought that must take place BEFORE you cinch up that respirator to your face.
In industry, OSHA requires this process: engineering controls, administrative controls and last PPE. This means first you must try and engineer out the threat. If that can't be done use control of exposure by rotating the people to reduce each s exposure (Share the pain, not used in my shops) and lastly PPE or Personal Protection Equipment. So if you can eliminate the risk by dust capture you are required to do so. This is the best way in our shops as well

In industry, the wear of respiratory protection REQUIRES a roughly 120 question questionnaire that is filled in and taken to the Doctor who does the respirator exam. And the reason for the exam is to see that your Cardio-pulmonary system is healthy enough to wear a respirator without causing harm to you. Now wait you ask, I want to wear a respirator to protect my...When you put a half or full face filtering respirator on your face your body has to work harder to pull air into your lungs. It has to overcome the restriction of the filters to get air in. This added stress can cause a heart attack in people with existing health issues. The doc will listen to your heart, listen to your lungs as you breathe and will perform a pulmonary function test in which the air volume of your lungs is measured. This becomes the base line and each year after it will again be measured to watch for changes. Most Doc's do a baseline lung X-ray as well.

So with that said if you will choose to wear a respirator, and not get that Doc's advice, you must really consider your own health. Do you have any issues in your cardio-pulmonary system. Consider well!

Once that first step is out of the way, there are many factors to now consider. A simple air purifying half face respirator is cheap and fairly effective. If you consider that a paper dust mask is not even considered a respirator in industry as they provide no real protection but are only allowed for nuisance dust, how do you know what respirator to choose?

First one should know the hierarchy of protection;
1. Paper dust mask=for nuisance dust IE dust that is not toxic
2. Half face air purifying respirator.
3. full face air purifying respirator
4. Supplied air respirator

As you go down that list the protection increases as does the cost. A supplied air respirator requires a special compressor or filter system, since a regular shop air compressor often generates Carbon monoxide in the process of compressing the air. Scary thought, lets fill my face mask with carbon monoxide!

Most folks go for the half face, air purifying respirator so I will be referring to that style form here on out. First thing, do not buy a respirator from a big box store if at all possible. Go to your local safety supply house and see if they have someone on staff who can train and fit you. Masks come in a huge assortment of sizes, materials and styles. The number of possible filters is scary big. A trained person to help you on the spot is of great value. And once you have found that person make them you best friend with a blacksmiths gift and they can often wholesale price all your safety needs, and boy will wholesale pricing be better then big box or online.

In short you need a mask that fits your face size, and no everybody is not the same. Got a beard? willing to shave? cause a regular face mask will not seal against facial hair. There are some solutions for a beard if you are willing to mortgage the house.

Once you have found the mask size material and size, now what filter? Here many people go wrong. For weld fume, you need a particulate filter. For paint vapor an Organic vapor cartridge. Many folks like to stack them and get protection from both. UNLESS you have both at the same time, don't do this, as it greatly increases the difficulty in pulling air in and increases your cardio-pulmonary stress.

Lets talk about fume vs vapor. In the safety world vapor is the term for a chemical that has changed state from a liquid to a gas, IE solvent in the paint evaporates and becomes a vapor that presents danger. Fume is from the French and is smoke. When you weld you make the metal liquid and some droplets become airborne and are so small that even when the cool and become solid they are small enough to be aerosols, of will stay in the air waiting to be breathed in.So the filters are very different for these two very different threats.

For weld fume and dust a particulate filter is used and these are rated by their efficiency in capturing what goes through them. HEPA is the term used in asbestos abatement that is now basically meaningless since every vacuum cleaner in the market starting referring to themselves as HEPA rated. That is patently false but I digress.

For a blacksmith, facing dust from grinding and fume from welding a N-95, P-95 or N-100 or P-100 filter is needed. These numbers mean N=not permissible. P=Permissible and the number is efficiency rating IE 95=95% of the particulate is captured, So what is the permissible part? It refers to is oil mist permitted when wearing against dust/fume. So if you have a dusty and oil misty shop you need the P rated. Please note that very few of us have a oil misty blacksmith shop, but if you do this P rating greatly increases the cost of the filter.

So what you ask do you wear in your shop against weld fume and dust? I always try for cross ventilation at the welding table. this removes the fume before it reaches my breathing zone. I have aquired and will install duct control at my grinders this winter. But when I am wearing protect against dust now, I wear a half face mask, with N-100 pancake filters because it fits under my weld helmet. The pancake filters have more surface area and allow easier breathing, and are a bit less expensive. Mine are labeled as protecting against particulate Radionuclides and are the old HEPA rated and are good for asbestos abatement. I always Seal check my mask. I also clean my mask often. 

Respirators need to be cared for as does any equipment. The air you exhale is laden with moisture and thus the inside of the mask gets coated in your bodies lung secretions. This will begin to grow mold and the like very quickly in my Midwest location, and I suspect most of the world is no different. When one buys a good respirator the device comes with disassembly instructions and cleaning instructions. Some of the lower cost half face respirators are disposable and are not intended to be cleaned. these are often used in industry for coatings applications where a worker ends his shift, and tosses the entire respirator instead of disassembling cleaning drying installing new filters and storing the unit. A bit expensive for the blacksmith shop. Follow the instructions provided. A couple of tips, the thin rubber disks that serve as inhalation and exhalation valves tear very easily so use caution to not tear. Use the cleaning agent as listed in the instructions, the rubbers used in the face mask body can be ruined by some chemicals.

If your shop is like mine, wasps, mud daubers and spider are pretty common. Either carefully examine the mask for critters before use or store in a Tupperware type container that has a very positive seal. Nothing quite like getting your mask on and seal checked only to discover that you are sharing you mask with an eight legged friend.

What is a seal check you ask? After you have the mask on and the straps adjusted, one covers the exhaust valves with palms, and breathes out. The mask should inflate a bit and then some air should escape. If air just blows out then you need to adjust the mask to get a better seal. Then you cover the inhalation valve and suck in a breath and the mask should collapse a little and you should be able to feel that it is sucked against your face. These 2 checks tell you that you are pulling your air through the filters and cleaning it instead of breathing air that bypassed the filters.

Filters do not last forever. Any damage to the filter is an obvious change moment. With dust filters you can have them actually blank off from dust and you can't get air thru. But that is rare and when to change is a bit harder o tell. When you see an obvious "Cake" or layer of dust, time to change. Never blow out filters with air, this damages them and you no longer get protected. Organic vapor filters are done when you get ANY solvent smell coming through.

Written by Jeff Reinhardt

Economy of Scale

A bit on the economy of scale; Ever wonder how you can buy a made in the USA 8$ sledge for $19.95? I hand made hammer from an experienced maker, who has a shop set up for the job with lots of equipment sells a hand hammer for at least $120. We in the one man shop the steel is cut manually. Usually in a band saw, maybe with multiple bars, but most are not auto feed. Then in the small shop each billet is heated and punched and heated and drifted and heated and forged and repeat till done. Then the head is hand rough ground, heat treated by hand and then tempered. next comes handling and varnish. The usually shipped in one in a box.

Now lets look at the industrial forge I worked in that forged hand hammers up to 12# sledges. Process was the same except for the press size for 1# to 12#. First a 10,000# bundle or so of first quality, steel with cert's and traceability was placed in the shear line and the banding cut. The unscrambler would feed a single bar at a time into the shear which stoked at about a 6-10 second rate second rate, and then the bars went into the conveyor for the induction heater. once thru the induction heater the billet was presented to the hammerman at the press, who set it vertically to make a bump hit, which broke the scale off, and started a slight dumbbell shape. Then the billet was laid on its side in the first impression. Hit and then the billet was advanced into the following 4 stations that fully shaped and as the billet hit the last station for trimming the next billet was presented. Each hit of the 5 impressions had about a 6-10 second cycle rate. And so once running a finished hammer head came off the press every 40 seconds or so, fully trimmed, almost to net size and hot enough to have the faces water quenched to give the modern slightly softer hardness.

Now the truth is those hammers from the press did not look as sexy as a hand made hammer with the cheeks, fullers and so forth, but the metallurgy was good, the forgings sound the cost impossible to beat. And if you want to spend the money for new dies the cheeks and fullers are no problem and off the come at 40 seconds each.

BUT and here is the big thing. You have to make enough of an item to spend the money for all that equipment. A 5000 ton or 7000 ton press, and the shear line and the induction heating line and the dies are a very expensive proposition. So we will continue to see high quality, hand made hammers from blacksmiths as long as we appreciate that sexy look.

Written by Jeff Reinhardt

Fire Extinguishers

A bit on Fire extinguishers: Having fire extinguishers in the shop is of course a great thing. So some fire extinguishers truths. A 10# dry powder extinguisher will spray for 9 to 13 seconds if you squeeze that handle and hold it. Yep 9-13 SECONDS. Unlike the movie guns that shoot forever without reloading, a fir extinguisher does run out, and quickly. Fire extinguishers are for "Incipient stage" fires. The firemen will tell you that is a small fire that is in the early stages.

Sooo... if a 10# sprays for only 9-13 seconds what use is it? If you catch a fire early 9-13 seconds of dry powder, sprayed at the base of the flames where the fuel is will usually put out a small fire.

Lets talk types of extinguishers. A bucket full of dry sand is works on metal fires but not at all on burning liquids. A bucket of water works great on burning wood or paper, but gets very exciting on electrical fires or burning liquids. So the folks that make the rules have a system where extinguishers are rated. 
type A is for burning solids like wood, paper and the like
Type B is for burning liquids like oil
Type C is for Electrical
Type D is for burning metals

Now if you go to the big box store you will find type A-B-C extinguishers. They work for all 3 and are the best choice for those of us who don't work with metals that will burn like magnesium.

So how do extinguishers work? Think of a fire as a 3 legged stool. It can only stand if all three legs are present. Fire needs three things to exist, Fuel, Heat and oxygen. Take any of the 3 away, and the fire can't burn. So when you toss a bucket of water on burning wood, the water flashes to steam pulling the heat out and no fire. Dry powder coats the fuel and prevents oxygen from reaching the fuel. A CO2 extinguisher blankets the fuel with extremely cold CO2, which both cools and excludes oxygen.

So now that we understand how the fire works and how to kill it, lets talk some practical bits about fire extinguishers. First the very best way to use a fire extinguisher is have it hanging on the wall and never use it. That's right never use it. We achieve that by planning and some discipline on our own part. Keep your shop as clean as you can of things that can burn. Bits of paper, rags etc. Stay in the shop and cleaning up for 30 minutes after any hot work achieves both a clean shop and some one observing for a fie that is smoldering. If you are going to quench with oil, keep the oil totally free of water, as it can flash to steam and cause a flaming eruption of oil. ONLY use a metal container with a good fitting lid for oil quench. Use a size container that will both contain the oil and the item being quenched if you drop it, and consider the volume of oil needed to pull out the heat. Quenching knives is much safer in a 5 gallon bucket of oil then in a quart.Plan a safe route out of the shop when quenching. I like to hang an extinguisher by every exit door of the shop. That way I can leave the shop, stand at the door and grab an extinguisher and THEN decide, in safety, if this is a fire I can handle with my 9-13 seconds of spray.

For those with hydraulic presses, these can be very useful machines, and also can present the threat of a fire throwing shop destroyer if a leak sprays hydraulic oil onto hot metal. These fires are usually not a single extinguisher type fire, but there are a couple of things one can do to make them maybe fight-able. Rig an E-stop that is at the door of the shop. That way, if the beast starts flame throwing you can retreat, slap the E-stop at the door as you exit. Once the pump stops, the pressure drops and then you have an oil fire not a flame thrower shooting flaming oil across the shop fire. You most likely still have a major fire and 911 is the first thing, then extinguishers from a safe exit point will maybe save the shop till the fire dept gets there. ( Note, this is not a theoretical fire issue, I have cleaned up several in industrial forges. Hydraulics are a blessing that carries the absolute, no if 
s,ands, or buts of leaks. All hydraulics leak. The only question is when and how much)

Sooo... you have you nice BIG 10# type A-B-C extinguishers at the doors and you get a fire. How do you use the extinguisher? Many folks use the P-A-S-S memory trick. That is;
Pull the pin
Aim at the base of the flames
Squeeze the handle
Sweep the spray a bit to fully cover the fuel.
I like to remind folks that the extinguisher is usually hanging on a pin. you have to LIFT the extinguisher to get it off the hanger. Now you are thinking the old guy has lost it. I have had to replace many hangers hat were either ripped off the wall or bent where in the excitement of a fire the folks forgot to lift and struggled a bit to get the extinguisher off the wall.

So you get that 10#er to the fire, what is this sweep stuff and how far do I stay away to do the job? You will hear things like 6-8 feet. I use Reinhardt's rule of eyebrows:
If you are spraying and hitting the fuel, you are close enough.
If you are hitting the fuel and your eyebrows are burning off you are too close.
If you are spraying and not hitting the fuel you are too far away.
IF YOU ARE SPRAYING, AND NOT HITTING THE FUEL, AND YOUR EYEBROWS ARE BURNING OFF, THE FIRE IS TOO BIG FOR YOUR EXTINGUISHER, GET OUT NOW!!!

What about care and feeding of your extinguishers? In industrial settings where a fire extinguisher tech is caring for your equipment they will check the overall condition monthly, checking that the Gage shows charged and no damage has occurred. CO2 extinguishers are high pressure compared to dry powder, and since the CO2 is liquid and flash to gas during use the Gage will show the same pressure till all the liquid has become gas before dropping. These have a TARE weight stamped near the valve mount. You add the tare weight to the rated weight IE 10# rated and say 6# tare and the extinguisher must weigh that or it has begun to lose charge.
A dry powder extinguisher is turned upside down and shaken vigorously every year at the annual inspection to "Unpack" the powder.Extinguisher get a hydro test every 6 years and often at the design life the extinguishers are pulled from service and sometimes become available to folks like us.They are usually fine, but you have to accept that they are past design life. If you do big festivals and take one there the fire dept folks are often checking an will usually note that they are out of date. I have never had a fire Marshall fail to accept a 5 gallon bucket of water as an acceptable extinguisher for a coal burning forge at a festival.

Last but not least, be aware that when you pull that trigger you get a huge spray of dry powder that flows much like water. Surprises some and they let up. don't let up, spray the fuel till the flames are gone then spray some more to prevent a re-ignite. CO2 will be loud, make a fog cloud and freezing anything in its path. Once yo use an extinguisher ANY, consider it dead till rebuilt. The flow across the valve seat usually damages the o-ring and the will leak down over time from that point. Dry powder is basically baking powder. It is NOT good to breath, and is corrosive to things like electrical panels and aluminum, so once the fire is safely out, start cleaning it out if possible or the panel is still savable.

Last, remember, things can be replaced, you can not be replaced. First GET out to a safe spot, look and call 911, and then fight a SMALL fire from the safety of a clear exit path and a good charged extinguisher.

Written by Jeff Reinhardt

Band Saw Blades

A bit on band saw blades. Band saws are one of the more common power tools in the blacksmith shop. A high quality blade will make a cheap saw perform much better and make a good band saw perform like a dream. Many of us have a cheap 4' x 6" horizontal/vertical band saw. I have three. I have a fine tooth on one, a much courser tooth blade on the second and the third gets mostly worn out blades as it is strictly a vertical saw, set on a bench and used for cutting curves. 
So why you ask do I use mostly worn out blades to cut curves? Because cutting curves dulls one side of the teeth. If you use a nice new sharp blade to cut curves it will want to cut curves when used as a cut off saw and you do not get square cuts.

Lets talk about teeth per inch versus stock thickness. A good rule to follow is to never have less then 3 teeth in the cut. IE a 1" thick piece could use a 3 tooth per inch, and a 1/2" thick could use a 6 tooth per inch and a 1/4" thick could use a 12 tooth per inch. Most folks don't have that many selections of blades. I try to keep a 28 tooth wavy pattern in one saw and a 9-14 tooth variable spaced in the other. The 28 tooth is good for stock down to 0.107 thickness. The 9-14 variable is great on stuff.214" and thicker. If you need to cheat a little you can use very light pressure and often get away with thinner stock then the 3 tooth rule says, but it is also easy to misjudge the pressure and strip a few teeth and then the blade is scrap.

Lets talk about blade materials. Blade teeth have to be harder then the stock being cut. They also have to stay hard when heated by cutting and hold that sharpness. Most of the 4" x 6" saws come with a carbon steel blade. Meaning high carbon and so the teeth are heat treated and the main blade body is not to allow flexibility to allow the blade to wrap around the saw wheels without snapping. These blades are short lived. I use a blade with M-42 tool steel teeth and a flexible back. Several brands are available. I have had the best life and durability from Lennox Diemaster II blades. In these tool steel tooth/flex back blades, the weld is super critical and I have had other blades suffer weld failure quickly, but get reliable blade welds and long life as well as very fast cutting from this brand. Been using them since about 1984 both at work and in my home shop.Starrett are also very good. The welds are made in a different system then the regular blade welders one see on the big shop band saws. These are best bought factory welded. Yes you can buy both carbon steel and hard tooth blades at the big box store. Yes they will cut some. I have found that with care, a Lennox Diemaster II blade will out cut a plain carbon steel blade at least 10;1, and maybe 15:1. The big box store hard tooth blades, seem to fail the welds in short order, even the name brands.

So what defines "With care" ? Follow the 3 tooth in the cut rule. When you put on a new blade, reduce the feed pressure for a few cuts. Don't cut hard stuff. Hard stuff that CAN be cut, but reduces life will produce blue chips. The blue is from the heat. Producing blue chips means you needed lubricant or you should have used an abrasive cut off saw, or you just accept lower life of the blade.

There are many solid stick lubricants that are used for drilling-tapping and sawing. These work well on the little 4" x 6" saws and are not messy like flood coolant. One has to apply often to keep the blade cool and lubed.

Besides stripping off teeth from too thin a material, the next quickest way to ruin a blade is to let the stock shift in the vise. That kinks the blade. The kink will often fail by snapping soon after the damage. Make sure you stock is very secure in the vise.

So you messed up and took a tooth or two off a still sharp blade? you can snap the blade to lengths for you hacksaw, and drill that flexible back and have some really excellent hack saw blades. Takes a little sting out of ruining a $28 blade to recycle it into maybe 6 or so hack saw blades.

Written by Jeff Reinhardt

Punch Lubricants

A bit on lubrication of forging tools. I have experience in both very large industrial shops forging millions of pounds a month, and in my own shop over many years. I will try to translate the industrial experience over to the home shop as I have done. In the closed die forging trade, lubrication or lack can make a die last 100,000 hits (forging blows in that impression) or a couple of hundred. When a set of large dies may cost $100,000+ this is very important. In the large valve shop I worked in, graphite in emulsion was the rule in the early 80's. Had been for maybe a century. But as time moved on the lube industry developed and improved a new better lubricant. These are the alkaline salt lubes. 
First lets look at the most severe forgings I have worked with and those are large heavy 6" flanged valve bodies. In these there is a 10" center mass, a 3" neck and the flange is 18" or so. The hot metal scrubs over that neck and tremendous checking and erosion of the hard H-13 dies occurs. Takes lots of tonnage as well. For these we used the industry standard of graphite powder in road tar mixed to the point that when heated with an open flame you got a toothpaste consistency. Every hit produced clouds of smoke from the tar, and dust from the graphite. That dust is respirable, which means it creates black lung in the operators if they breath it. The dies lasted maybe 4000 hits before a 1/4 to 1/2" was ground off the top and the die re-sunk. Since those dies were about 5' by 8' that is a lot of grinding and re-sinking. We switched to an early water based alkaline lube, and the smoke was almost gone no dust, and die life jumped by at least 5 times. In the early 2000's at the Upsetter shop they were using a brand new Henkle lube that was an alkaline salt and it was astounding better then anything I had seen. dies that had been giving 20,000 hits were giving 100,000 and filling out better. tonnage was less and these machines had tonnage monitors and the data was real not a guess. These machines were using a 5% ratio lube to water to pull the heat out of the dies which were making a hit every 6 seconds.

So how does this affect how my hobby shop works you ask? The forge engineers saw my blacksmiths plate on the car and were interested and shared the lube info. They suggested I drain some dregs from an empty tote and try it at home. I did and WOW! I had been using plain water to cool hot cuts and coal dust for punching. I had seen the graphite and soap mixes used by many and watched them just fall off. This stuff made a well attached coating and I can tell you the first hot cut blow sent the hot cut through the iron and into the anvil face something that had not happened before this lube. I experimented and found that a 50:50 mix worked best for how blacksmiths work vs how an industrial press works. Time went by and at a demo Tom Clark was showing how to make a hammer and spilled his graphite in soapy water. He had no more, so I told him that I had this industrial stuff and it was great. He tried it and boy was he impressed. Gave him the quart I had. (He gave me tongs:) ) A few weeks later I got a call and he asked could he drain some totes. I said yes if he had a jug. He drove 500 miles out of his way and got that lube from empty totes. The forge engineers saw us and offered him some early alkaline salt lube sample if I would not kill them for having sample without the MSDS as I was also the safety guy. He took maybe 20 5 gallon pails with him. Later he bought this product and resold it

Time went by, and Henkle became very difficult to deal with for tiny orders like a 5 gallon pail. Fuchs stepped up and they offered me a sample. Worked a treat and I have used it since. The BFH team has used it to carve wizards from 3" square stock to cool all the tools. We later did an anchor from 2" round bar and doing the mortise for the vertical bar to a 1.75" square hole was actually very easy with this lube.

So if you like smoke and flames and noxious fumes indeed continue to use coal dust or never-seize, or grease or table salt or heck just spit on it. If you want less effort, no smoke, non-toxic and tools that lat much longer, get your Fuchs on. This should be a 50:50 ratio, and lasts for a very long time. For short tools like hot cuts and handled punches a smaller amount works. For long drifts get enough to fill a deep but smaller diameter tank. If you don't spill it it will go for many years in a home shop. Just dip a hot tool in and pull out. if the lube is wet, not hot enough. if the lube sticks above and below the hottest spot redip it is still too hot.

Be aware that no lube can overcome the material properties of the tool. That is; if you get the end of the tool too hot and it mushrooms, it won't weld in but it will become an expensive ball and socket joint. I dip punches and cuts every few hits. The lube makes them move metal like they are on ball bearings so be cautious until you find out the change in resistance.

The product can be obtained from

Forge Ease 3512 steel forging punching lubricant. : DEMPSEYS FORGE anvilfire.com Store

A clean water soluble lubricant used for hot forging steel parts and blacksmith hand punching. FORGE EASE can be used for most…

Written by Jeff Reinhardt