How to make a Thread Cutting Die from Scratch – Watchmaking Vlog #12
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How to make a Thread Cutting Die from Scratch – Watchmaking Vlog #12


Welcome guys, in this video I’m going to demonstrate
to you how I make a die from this bit of steel to make screw threads. Just really quickly before I pad off, I don’t
have a padding tool that has the length to cut all the way through this material so I’m
just going to use a handsaw and go really slow just to make sure I don’t, um, slip and
hit the base of the lathe which is a way that many lathes get damaged. So now that the hole is tapped it’s time to
create the cutting edges of the die. So, this is an M4 die it’s a lot larger than
the one that I’m making. But the principle is the same. So, it has these three holes around the center
hole which, um, formed these cutting edges. Basically, I’m going to try and recreate the
same thing but in a smaller die. To achieve that I’m basically using some different
attachments that come with the lathe, let me show you what’s going on. This dividing head is a 40 to one worm gear
ratio. I’m using the, ah, 21-hole pattern plate so
to get three evenly spaced holes at 120 degrees apart. I’m going to have to do each hole at 13 for
revolutions and then seven-hole spaces, I’ve already centered the two holes using the center. And I’ve already offset it approximately one
millimeter. So, this is what the die looks like at the
moment. There was a thin bit of material left around
the center hole as these three holes didn’t quite break through. It was very thin. I used the driller saw to make the small incisions
and I cleaned it up and I cleaned the barrel up with a fine rectal needle file and just
ran the surfaces of some 200-grit emery paper. So now the machining is finished to make the
die. I need to harden and temper the tool so the
way I do that is I made this little container out of copper tubing just like this stuff. So, this not only helps hold the pot but the
copper is a great conductor of heat and makes like a little oven in there so that heat doesn’t
dissipate away and you can get a more even distribution of heat. So, I’m going to heat up the die now to a
cherry red quenching in water. It is a water hardening carbon steel and then
I’m going to give it a quick polish and temper it to a light straw color. Here’s the die after hardening as you can
see it’s a like a matte gray color. I’m just going to wash this in a bit of denatured
alcohol and then I’m going to clean it up and temper it. So now to temper the tool I’m going to use
an alcohol lamp with denatured alcohol and I have a small brass little pot that I’m going
to fill with these brass chips from turning in the lathe. The reason for this is the brass distributes
heat quite evenly so it’s the best chance that I have to heat the tool completely in
a uniform manner. This is my backup alcohol lamp. The one that I use mostly has an adjusting
knob to move the wick up and down and a much thinner wick like a quarter inch wick. I think this is the half inch wick. It’s probably too thick for what I need. So, the flame is a bit big. I’m a do my best. I don’t know why with this alcohol lamp it’s
getting a lot of carbon. I don’t have that with my other one it burns
quite clean but it should still do the job, so it’s turning now. It’s a bit of a straw yellow. I’m going to pull the die out. Let’s have a close look. So, it’s got a straw color over the tool. Thanks for watching this video. Tune into the next episode to see if I can
actually turn a steel screw with this die that I made for my watch. And as always thanks for watching. If you enjoyed this video give it a thumbs
up. If you want to see any of my upcoming videos
hit that subscribe button. And if you have any questions or something
you want to say feel free to leave it in the comments section below.

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