Generally useful tools, in this case Updated

A prick punch and center punch, beginning to end.

NOTE: If you want to make these, please remember that this method involves cutting tools, power tools, and torches, and if you don't pay attention to what you're doing you WILL GET HURT.  And if you do, it's your own damn fault so don't yell at me.

First, the terms: most of you know a center punch: a relatively blunt point, used to make a deep punch mark, good for starting a drill bit without it walking away from the spot.

A prick punch has a much slimmer, finer point.  Easy to move along a scribed or marked line and put in the exact spot you want the hole.  But unlike the center punch, you only use a light tap on this one; its job is to mark the spot precisely, then you use the center punch to deepen the mark.

This is a stone drill, the kind you hit with a hammer, and it makes a 5/16” hole.

Good steel, excellent for the purposes.  A lot of these, the shank either isn’t hardened or is to a much lower degree than the cutting end; for that matter I’ve seen some where the cutting end wasn’t very hard.  Either case, you can usually cut the piece with a hacksaw.  In this case, it gives two pieces five inches long*.

 If the whole thing is hardened, mark the spots where you want to cut and use the torch to heat them up to a low red, then let it cool; that should normalize those areas enough to let the saw cut.

For punches, here’s the two tools that do most of the work for me: drill or driver, and the belt/disc sander.

Chuck one of the pieces into the drill, and start grinding.  First thing I do is bevel the striking end so it’s smooth and has no corners.

Second, turn it around in the drill and use a low angle to taper the other end.

Third, form the point.
Yes, it’ll get hot on that end, hot enough to soften it.  Since you're going to have to heat-treat it, not a problem.***

They’ll work as-is, but they'll dull the first time you use them; much better to heat-treat them, and on small stock like this a cup of water and a propane torch will do.  For heavier stock you’ll need something a bit hotter(and something with more volume for the coolant), as you need to get the point section up to at least a low-red heat, ideal is a medium- or cherry-red.  Do NOT try to get the thing as hot as possible, you’ll damage the structure and ruin that section(yes, you can anneal it and start over, but let's keep this simple).

Short digression: steel has a grain structure, and the finer you keep it the better.  The first stage of heat-treating is hardening: get the piece, or- as in this case- the section of it you need to harden- up to critical temperature** and then quench it, cool it very fast.  Get the steel another 50 to 100F above critical and the grain structure starts to enlarge, and the hotter it gets the worse; if you harden it then it'll look fine, but it'll have a coarse structure that's weak.  Much more prone to chipping or breaking.
This stuff isn’t a air-hardening steel, which hardens just from being brought up to heat and then letting it cool in air; it has to be quenched in water(preferably hot to reduce the amount of shock to the steel) or oil(also better heated; not only to reduce shock but to make it flow better for a more even quench.  Not too critical on a piece like this, very critical on a blade of any sort).  Most of the stuff I’ve worked with, critical temp is 1500F, plus or minus 50; that medium or cherry-red is it, and you can learn to see it; or can use a Tempilstik, or a thermometer like this, to check it.

In this case water will do nicely, so get a cup ready.  All you need or want to heat here is the area up to about a half-inch from the point; that’s the part that has to be hard, and this leaves a softer shank to absorb shock and for the hammer to strike.  Find a shady spot so you can see the color and start heating the end,

turning it to keep it even.  I try to keep the tip of the flame about 1/2" back from the point; if you put it ON the point that'll heat fast, true; but I want more than just the point to be hard, so I actually get from the point about 1/4-3/8" back to the required color, and when it looks right stick it in the water.   Swirl it around a bit, won’t take long for a small piece to cool.

I like to check for hardness with a fine file.  Just stroke it lightly on the hardened area, and if you did it right the file will skate over without biting; if it does bite, either you didn’t have it quite hot enough or it’s not the high-carbon steel you thought(yes, I’ve had that occur; damn cheap drills or files).

Back to the grinder, this time just touch it lightly, to shine up the surface.

The second step of heat-treatment is tempering; heat the piece up again, but to a much lower temperature.  Hardened high-carbon steel is highly-stressed and brittle; idea is to use sufficient heat to relieve enough of the stresses so it’s not brittle, but leave enough that it’s still hard enough not to dull when you whack it.

If need, can hold the shank with pliers, though since you’re mainly heating the sharp end I can usually just hold it by hand.  Hold it point angled upward and start heating no less than an inch below the hardened area;

if you’ve got a torch with a pinpoint head you can start a bit closer, with a wide flame further back.  And turn the flame down a bit; slow is good here.  Keep the piece turning and watch for colors(and yes, you can hold it in the drill and spin slowly if you wish).  The first you’ll see is a very faint yellow appear that should flow up toward the point; behind that it’ll darken into a dark yellow, then into a bronze.   For this tool I like light-to-medium bronze as the stopping point.  Once the yellow is moving up to the point you can usually remove the torch; should be hot enough in the area you heated for heat to keep flowing up the piece.  And soon as the desired color reaches the point, quench it to stop the process.  It should look something like this

If need,  sharpen the point and test it on a piece of suitable metal.  And that’s it.

If you want to practice the tempering to get used to the colors, just shine up a piece of steel, any shape, and then heat it and watch.  Kind of fascinating to observe as the colors appear and march along.

And if you need a small, fine chisel, this stuff works well for that too.  For a chisel you just grind the two sides flat for the main bevel.

On one this small, I prefer to grind the main bevels, then harden & temper(same as on the punches, then grind the edge bevel.  Depending on exact purpose and what you expect to use it on, can use a fairly blunt edge bevel, or a very thin.

I had a third piece of stock available, so made one of each: prick punch, center punch and chisel

Closer look at the working ends

The punches are right after tempering, the chisel I shined up when ground the edge bevels.

Update: Tried this with music wire, full info here




*Nice thing about making these, you can make them as long or short as suits our purpose.
**Depending on the alloy, critical temp can vary from 1500 to over 2000F for some of the air-hardening tool steels; some of those also need a controlled-atmosphere for best results, and that can get complicated.  Which is why a lot of knifemakers who work with those steels send them to a specialist for heat-treating.
***You can use this setup to resharpen a punch that's dull; since that should already be hardened, take it slow and have some water to dip it in to keep it from overheating.  Which can happen a lot faster than you might think.