Tony Bartol Forging Primer
Forging Primer. Knives, Carving tools.
Kettle Karvers, March 2016
Copyright: YNot Engineering LLC.
First must come the desire to Accomplish. If safety is first, nothing gets done.
Second comes educating yourself well enough that you will accomplish in a SAFE
effective manner. This information is NOT all inclusive and NOT all that needs to
be known and done to be safe in your situation.
Third, be safe. Don’t burn or explode yourself or your property, Don’t breath
fumes or dust. Protect your eyes from flying debris. Don’t damage your hearing.
Stay hydrated. Don’t eat poison or walk off cliffs.
If you can’t take a little burn, you should not attempt forging. You WILL get burned.
Need: Steel. Hammer. Anvil. Heat. Magnet. Quench medium. File. Means to sharpen.
Do: Heat, Beat, Repeat… until slightly oversize but close shape, Rough grind or file but do not sharpen at all, Heat to non
magnetic, Quench, Temper, Finish Grind, Handle.
Plan your work. The steel will have a constant volume. You are just moving it from the shape it starts in to your shape.
Selecting a shape and size that reduces hammering is far easier. THINK and Plan how you will move it. Do not start with
your expensive steel and DO treat it like a game. The steel will laugh at you until you learn to work with it.
Set up your work area for efficient movement with no burning tripping or bumping. Anvil should not move around at all
and should be at knuckle height when standing.
Forge: Heat with extra controllable air is required. A lazy fire such as a campfire will not get hot enough. A hardwood fire
with good coals and a hair dryer to blow more air in on the COALS from the side or bottom is the minimum. Building that
fire on some insulating fire brick and a trough in the brick to aim the hair dryer into is better. Adding some firebrick sides
is better yet. Adding a tuyere (look it up) is much better yet. Don’t use mineral coal. It is dirty and the fumes are very
bad. Heat to orange, not yellow.
A good plumbers propane torch or two, aimed into a firebrick box is good. Kaowool ceramic insulation inside the firebrick
helps immensely. Fiberglass building insulation will melt. A zircon coating on the ceramic wool is fabulous. Durock cement
tile backer board makes a good base to build firebrick on. Firecode drywall also works but is not durable and will crumble
Reduce the air amount to reduce scaling on the part. Cover some air holes on the torch.
You need enough air in the flame to get the part hot enough, but too much air turns more of your steel to scale than
necessary. Some scaling will occur.
Anvil: Does not need to be a anvil shaped object with a hard totally flat surface to start, although that is most efficient.
Should weigh at least 50 pounds. Any steel will work to start. A section of railroad rail is quite good. A large rock with a
reasonably smooth flat spot will work quite well at long as you don’t hit and chip it with the hammer and it is dry. Wet
rocks can explode. Rocks don’t suck heat out of the steel as much as an anvil. Metal forging was done with a rock
hammer and rock anvil for a long time before steel anvils were made.
Hammer: For this size work, even a 16oz. claw or ball peen hammer will work. A rock will work. Hammer head should be
slightly domed with no sharp edge. No loose handle!
Hammering is a dance, not a bludgeon. No death grip. Start slow to reduce chance of tennis elbow. Beginning hammering
will be frustrating. Only practice makes it better. You are aiming for the anvil surface, not the steel surface. Hammer
through the steel. Try not to pull hammering short, rather use less starting force for lighter hits.
Use a long piece of stock so you have a handle and do not need tongs. Cut your part off when ready to temper. Nomex
gloves are best. Oven mitts and insulated leather gloves can work. DO NOT USE WET GLOVES or you may get steam
burns. Try not to overheat the steel as the grain size will grow and reduce sharpness and edge holding.
Tongs are good. However, vise grips were invented by a smith as a tong alternative. Hammering action can spit the steel
out of the tongs or vice grip, so plan on hot steel flying around sooner or later when you are not paying enough
Once you have Heat, Beat and Repeat to the slightly oversized shape you desire, rough grind or file while the part is soft.
This is much easier than doing all the grinding and shaping after hardening. Leave the edge about 1/16” thick to avoid
cracking during quench. Avoid sharp corners which may crack during quench.
Quench to harden: Soft steel will not take and hold a sharp edge. Heat at least the part you want sharp until the magnet
no longer “sticks” and then a little more and quickly quench. It must be non magnetic when it goes in the quench. Do
not swish the part sideways, but along the axis of the part is good. Use only metal containers for quench liquids and use
about a gallon for a small chisel sized part. Water can turn to steam and boil. Oil can get too hot if you don’t have
enough of it, bubble over, and start on fire. Have and cover burning oil with a metal cover to extinguish. Cooking oil can
be used for oil hardening steel. A little salt and dish soap should be added to water for most water quench steel. Leftover
Bacon fat and oil is a great smelling quench for 5160.
Bacon is good for everything!
Let the part get to room temperature for full hardness potential. Now the part is hard, but may be very brittle so be
careful not to break it. Test it near the cutting edge with the file. The file should “skate” on it if hard and not cut in. If it is
not hard, you did something not per directions or the steel is not hardenable by typical forge methods. Reheat to
orange, let cool very slowly to normalize the grain structure and retry the quench sequence or get different steel.
Tempering: This is reheating to a lower than forging temperature, modifying the crystal structure, to make the steel
tough enough to use without breaking, but hard enough to take and hold a sharp edge. For small parts, and simple
steels, tempering in a good kitchen or toaster oven is very effective. DO get an oven thermometer to check the temp
setting. Most steel will be very hard if tempered at 300 degrees and some will crack when used at that hardness. 500
degree temper will make most steels usable but soft enough that they will need frequent sharpening. Tempering should
be done as soon as possible after the part gets to room temperature after quenching to avoid cracking. Have the oven at
temp before you quench. Temper for 2 hours. Tempering up to three times can increase edge life.
“Differential tempering” or “running the colors” also works but is not as effective and can take much practice. Polish the
sharp end so you can see the colors, heat the handle end of the part with a torch slowly. Watch the colors work toward
the sharp edge SLOWLY and quench only the edge again when a light straw color gets to it.
Files and sandpaper or stones can be used to sharpen. A 1” by 30” belt grinder and belts from 80 to 600 grit will be
MUCH faster. Be careful not to overheat the edge while sharpening or you will have tempered it softer and it will not hold
an edge. Test the edge by whacking it into wood. The edge will crack if too hard and fold over if too soft.
Practicing with your steel and methods by forging, quenching, tempering, sharpening and whacking an easy test blade is
a good idea until you get it right.
Once you are satisfied that you have a usable hardened sharp part, glue on a handle. 30 minute epoxy or JB weld work
well. Drill an oversize hole, put in some epoxy, push in your handle until epoxy comes out and allow to set. Carve and
sand the handle to fit.
Now you are an accomplished carving tool or knife maker!
Old car leaf springs are usually 5160 steel and work very well. Easy to heat treat, tough, and reasonably long edge wear.
Most spring steels are usually a good start. Avoid steel with cracks. Rust will scale off. Some new hard steels do not
forge or heat treat well.
Spark test (look it up) unknown steel with a grinder as compared to angle iron. More sparks and smaller sparks is better.
Then test quench in oil then water to see if it gets hard.
This is a primer. None of the topics have been thoroughly discussed here. You tube!
Don’t take this too seriously at the start. Have fun! Just get some old leaf spring or order some O-1 oil quench rod, heat
it, beat it, quench it in old cooking oil with a bacon grease smell adder, temper it in the toaster oven at 400 degrees,
sharpen it and use it! It will work and you will have made it!
MSCdirect.com. ¼” x 36” O-1 tool steel drill rod. Part number 06000160. $4