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Discussion Starter · #1 ·
Well I had to stay home today so they could install my new HVAC unit so I made the best of it (please don't throw me in that there briar patch). I spent the day in the shop making chasing tools. I used a modified system similar to what Fred Holder described using a tap.
I took a nut of the appropriate size and cut a slot that fit the metal that I used to make the tools. Then I made a cut in the back of the nut to act as a sort of hinge.
I insert the steel into the nut so it sticks slightly deeper than the threads and clamp the whole thing in vise. Then I just run a tap down through the nut threading the steel. It’s a little hard to get started straight but once you make a couple of revolutions it cuts right down.
To improve the threads I took a triangular file and carefully matched the angle of the threads and took the same number of passes on each tooth down the middle to create a deeper and sharper tooth. I also filed off the outside partial tooth. Try not to change the angle of the tooth. I filed the 16TPI outside cutter at a slight angle accidentally. It cut as fast as a 10 tooth threader. I went back and filed the teeth almost perpendicular to the top surface and now it is very controllable. I polished the top side of the tools using diamond hones.
I made 2 tools. One using a 5/8 x 10 tap and one using a 7/16x16 tap. You can’t use a small nut so instead of using a 1/4x20 tap use a 1/2x20 fine thread tap to get 20 TPI. I made these from some tool steel that I had. I think you could make these from old chisels by annealing the tip cutting the threads and then reharding and tempering. If you need to know how to do that just send me an e-mail and I can send you a document on heat treating. I haven’t tried using a chisel yet but it should work. If I have time I’ll try it this weekend.
 

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John, I'll tell you the ingenuity of some of you guys just blow me away. That is very cool and the pictures allow me to understand exactly what you were doing. Awesome! I saw the Tim Yoder show on turning threads just the other day. (Catching up on my dvr!) I looked at some thread turning tools at the local store and at around 80 bucks for the pair I not quite ready for them yet. I still need to work on just turning the lidded box. Anyway great job and thanks for sharing. given some spare time I may grab Dad's tap and die set and give that a shot.

John
 

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Discussion Starter · #5 ·
Fred Holder's book on Screw threading is good. There are also several video's out there but I don't remember which ones I've watched.
 
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