Down'n'dirty Blacksmithing/Hot Cutting< Down'n'dirty Blacksmithing
Hot cutting, as implied, is a method of cutting to length the piece of metal that you are working on. The most important thing to remember is not to cut the whole way through the piece. Hot flying metal seems to have a liking for skin. Trying to explain to the doctor at emergency why you have a fresh brand mark on your hide invites some very interesting conversation. Safety glasses are a must too
A hot cut chisel is ground or forged to thirty degrees instead of the sixty degrees a common cold chisel is. The point may be centered in the chisel or offset to one side.
Both chisels have their uses. When hot cutting with the point in the center of the chisel, metal will be pushed equally to both sides. When the point is offset to one side, metal is pushed one way only so a straighter, squarer cut may result.
To make a hot cut is a three handed job. If you don’t have the third hand, have someone help you or have a separate way to hold the steel in place. The first thing to do when hot cutting is to get the steel to a bright yellow heat where you want to cut it. Remember that as you cut the steel it will heat the chisel tip. So you need to cool off the tip on a regular basis so a can of water nearby is a necessity. A word of caution: do not use the face of your anvil to cut on because if you go too deep or miss with a chisel you will damage the surface of your anvil. Use a sacrificial piece of scrap metal on top of your anvil. Ideally, you would use a soft metal, such as copper or aluminum, to preserve the sharpness of the chisel's edge.
There are two basic ways to make a hot cut: one is from one side only and is usual only done with thin stock. The idea is start cutting from the top down until you are almost through the whole piece. Stop before you are all the way through the piece. Work the steel at cut point back and forth until the last little bit work hardens and breaks off.
The second way is to cut to the mid point of the piece of steel and flip it over to finish it with a second cut. Once again it is important to leave a small piece to be broken off by hand.
With a center point hot cut chisel the metal is pushed to both sides. Piece is flipped and the cut continued on the other side.
With an offset point a straighter cut may be made. Piece is flipped and the cut continued on the other side.
Another approach is to use a hot-cut hardy tool. This is essentially a hot cut chisel with a "handle" the right shape to fit in your hardy hole. This frees up a hand, but care is needed to strike squarely, to avoid cutting your hammer.
Even handier is a 2-sided springed hot cut hardy tool, which is sort of like a big nipper to fit in the hardy hole. You hit the top cut, driving it down onto the work to be cut, which is driven onto the lower cut. This cuts both sides of the work at once and avoids scarring either anvil or hammer.
Next Chapter: Exercise 3: Drawing