Draw Dies

[IllinoisCoyoteHunter]

I’m in the process of making some swaging equipment for the Corbin CSP-2 Mega Mite. I have machines a 1.5-12 die holder, similar to the external punch holder provided with the press. My plan is to drill it .875 through. Then I plan to counterbore the opening 1.25 diameter and using a retaining nut similar to an er collet nut to retain the die in the c-bore. I’d really like to draw jackets in swage mode, which has a 2.4” stroke. There is also an intermediate stroke length setting of 4”, but as we know you lose a little leverage as the stroke lengthens. I’m not getting any younger and would like to use the shorter stroke for drawing jackets. If I intend to do this, I’d like to pick your brains on drawing dies. I guess my main question would be if I can get away with my dies only being 1/2” long? I understand that the actually land of the sizing portion of the die is relatively short, but I’m curious about length of tapers/lead ins, etc. I plan on using the through hole in the retaining nut as a spot where my punch guide (which will slip over my punch and hold the cup) can seat into and square up my punch before pushing the cup through the die.

I haven’t drilled or counterbored my die holder yet. I’d like to hear what you guys think. Thanks!!

*On a side note, I know my dies don’t need to be 1.25 diameter, but I run a job at work several times a year and get 2” long pieces of O6 off fall. I probably have saved up 30 or so pcs lol.

[deltaenterprizes]

The drawing portion of the Corbin Derimming Die is only about 3/8-1/2” long.
Look online for a book called “Ammunition Making “ by Frost, it has plenty of drawings on making drawing dies.

[IllinoisCoyoteHunter]

That’s some great info there! Thanks for that! That gets me going in the right direction.

[midnight]

I like to make draw die with a parallel section close to the length of the donor jacket to keep it square to the ring that draws the jacket down. This way you get square mouths and more uniform wall thickness.

Bob

[IllinoisCoyoteHunter]

That makes sense Bob and I agree. I plan on drawing copper cups (after blanking and initial cupping). I have a feeling there’s gonna be lots of trial and error.

[Cris T]

I don't know if you have ever watched these videos but you may see something here that can help: (I believe this is a 9 part series)

[IllinoisCoyoteHunter]

Yep I’ve watched those videos. He is a member on here. Lots of good info in that video series. Thanks for posting that!!

[IllinoisCoyoteHunter]

This is my draw die holder.



Spacer so components don’t get jammed up in the die body. This insert is for 22lr cases to ride up and out of the die.

[deltaenterprizes]

I don't know if you have ever watched these videos but you may see something here that can help: (I believe this is a 9 part series)

Thanks for sharing!

[IllinoisCoyoteHunter]

[IllinoisCoyoteHunter]

Finished up the derim die. O6 tool steel at 60 RC. Seems to be just fine. Was able to keep the press in swage mode which makes derimming a breeze.

[IllinoisCoyoteHunter]

https://youtube.com/shorts/6ivM60wn7Kw?feature=share

[deltaenterprizes]

Your press looks like my Corbin S press

[IllinoisCoyoteHunter]

The press is a CSP-2 Mega Mite.

[IllinoisCoyoteHunter]

https://m.youtube.com/watch?v=gYbXdkPG28s

[deltaenterprizes]

https://m.youtube.com/watch?v=gYbXdkPG28s

Yes, that is a little bit bigger than my S press!

[dimaprok]

https://m.youtube.com/watch?v=gYbXdkPG28s

When you repositioned the camera I noticed your previous case was sticking out quite a bit, maybe 1/4"? I was expecting the next case would crush it! How is that not happening? The finished-sized case from your earlier video looks really good with no crevice from the rim. I've tried my hand at making 22 derim die and had promising results but it opened up too much during lapping. I need to redo it with tool steel and I am going to do 2 part so I don't have to deal with having to lap such a long 1 piece die. I am also pretty new to the whole lapping thing. How did you do the lapping part?

[IllinoisCoyoteHunter]

Great question! The sizing die has a very short land that is machined to .220 or .221 (can’t remember off the top of my head) and a very generous lead in, which is polished with a Drewel and polishing compound after heat treat. The length of the sizing land, being very short (.03-.05”), allows the next case to finish pushing the previous case through without any damage to either case. Once the case rim is ironed out, all the hard Work is done. The back portion of the die is also relieved. Another thing that I think helps is putting a rather small radius on the punch, which happens to measure .199 and is made of hardened drill rod. This die was cnc machined by drilling and then finish boring with a solid carbide boring bar. Hardly any real polishing was needed as the boring bar leaves an excellent finish.

[IllinoisCoyoteHunter]

The pic below shows the opening of the die where the case enters. Notice the generous lead in and the short sizing land.



This is a pic of the backside of the die. Notice the relieved section just after the sizing land. THIS is what allows the next case to push the previous case through the die the rest of the way. The entire die is only .530” long.

[IllinoisCoyoteHunter]

This is the profile of my derim die. The second pic I zoomed in and highlighted the radii in red.

The through hole is .220-.221 and I use a .199 pre-hardened M2 Drill rod as my punch with a slight radius on the edge.