Draw Die Help

[Valornor]

I have some friends who have fancy tools, and who are willing to help me make some draw dies to turn .223 cases into .338 jackets. I already take .375 copper tubing and reduce it to .338 diameter. From what I understand brass isn't as easy to work as copper and so I will need a intermediary draw step. I'm having a hard time figuring out what should be the first draw but looking at the cases it would seem to me making the case a uniform diameter is a good place to start.

I have some experience with designing tooling, but not draw dies or punches. Here's a rough draft of what I am thinking, any help in this would be appreciated.


I was thinking of making it out of A2, but I am not a machinist so I would defer to those whom have more experience in order to choose materials.

[clodhopper]

I would recommend a shallower angle leading to small diameter, more like 5 or 10 degrees.

[fast ronnie]

D-2 is a little more stable in heat-treat. It is also more abrasion resistant. Both can be hardened to about 60-62 rc. (cutting tool Hard) If well polished, should work for a loooong time.

[midnight]

Why not make your intermediate die .355 or .356. A .358 jacket is a little too big for 35 caliber bullets. If your intermediate die produces a usable jacket, that's a bonus. You never know when you'll find a 35 Whelen you can't resist. It happened to me.

Bob

[Valornor]

Good point midnight. I've done some load development for 35 Whelen, and I have to say I am not a huge fan of the cartridge. I have never quite figured out what it offers over a .30 Cal besides increased recoil. I don't own a rifle in 35 Cal, but should the mood hit you never know.

With annealed cartridge brass how much spring back can one expect? I haven't measure the ID of my .338 draw die, I suspect it is something less then .336. I need to take some measurements. I am presuming that the same draw die I use with copper tubing will work but then again, if the brass springs back to a large enough diameter I might be in for a surprise when I try to trim the jackets to final length prior to core seating.

I'll edit the lead in angle, and the material. As far as I know we don't use any D2 for the tooling we do where I work. So I've never even worked with it, I will definitely look into it.

[midnight]

I always assume .001 spring back but I finish ream a couple thousandths undersize and polish out from there. I keep running jackets through the die and polishing until the jacket comes out the diameter I want. The actual ID is meaningless if it produces ths jacket diameter you want.

Bob

[Valornor]

That makes sense, I'll give my machinist friend a bag of annealed brass cut just behind the shoulder, and see what he can do.

I was thinking though in terms of draw dies. Would it be cheaper and easier to have a die holder made of some relatively soft free machining inexpensive steel such as 12L14, or perhaps something like 4140 that is threaded on the outside to 1.5-12 that will fit in my press head. Instead of using one large chunk of tool steel, we have small inserts that interchange out of the tool head. The concept would be that I could set the tool holder up once, and changing out draw die sizes is a simple as loosening up a couple allen screws popping out the die, popping in the new die and tightening things back up again. Then also changing out punches. I would think this would greatly reduce the cost of making a new draw die.

[midnight]

I use the die holder method you describe. Mine are 7/8-14 and I use B7 threaded rod as the die holder except that I make my dies from drill bushings and make them a really tight press fit in the die holder along with some red loctite. I tried making the bushings removable but it didn't work for me using set screws. The die must be held tightly or it will pull out when a jacket sticks on the punch. You have an advantage using 1 1/2-12 die holders. You have enough material to thread a die retainer into the bottom of the die, in fact it would be exactly like my lead wire extrusion dies except the die would be on the bottom instead of the top. If you use drill bushings they will have differing ODs. Some are 1/2, 5/8, or metric so all you would need would be a die retainer for each bushing OD that you use.

Bob

[PWS]

I've had pretty good luck with very little to no spring back from fully annealed cartridge brass. That said, your plan of supplying your machinist friend samples is the best way to get a die that produces jackets the size you want.

I would also second the shallower lead angle and keep the parallel section like you have in your drawings. I've found that a sizer that is tapered to the exit tends to produce a banana shape and a short parallel section prevents this for some reason.

Also like the insert idea! That'll save a lot of machining and should work well provided the inserts are long enough.

[bullet maker 57]

The draw dies I have use a snap wring in the bottom to hold the insert in. Works for me.

[Valornor]

Cool, I'll see about putting together a new print with the changes. Thanks for all the input!

[Valornor]

Ok, it took me a day to find the time to make the edits. Here is the current revisions with the suggested changes. I made the draw die reversible with a 5 Deg taper on one side and a 10 deg taper on the other. I'm not sure which will work better, they may both work equally well, one may have an advantage over another. I changed the die diameter to .355 so it will make jackets suitable for 35 Cal bullets. This die would also set the template for any additional draw dies that can interchange with the die housing.

Take a look and let me know what you think. Also if there's any machinists who have time on their lathes, or would like to shoot me a PM with a quote on what it will cost to have you make them for me I'd appreciate that. I have a friend who would be willing to do it, but he doesn't know when he might have time to get to it. I like to explore the options.



Thanks for your input,

Jared

[clodhopper]

The taper lead in to the die might be best if the machinist can what ever use the tapered reamer he has.
Specifying 5 and 10 degree leads will add substantially to set up time or tooling cost.

[Valornor]

That is a good point.

I do not have much experience at all when it comes to draw dies, for what I am trying to do how important is the lead in angle? What range of angles will work for this sort of operation?

[clodhopper]

Any gentile angle that will help guide the work piece squarely into the die.

[IllinoisCoyoteHunter]

Very nice drawings! Just what I need...more projects!

[DAVE A]

If you make the die reversible you may have problems stripping the jacket from the punch.

[IllinoisCoyoteHunter]

So maybe just a counterbore on the "topside" of the sizing bushing? Or, just make it smaller (shorter), or make the lead in longer.

[Valornor]

Hmmm, that is a good point. Currently when I draw .375 tubing down to .338 cal the press stroke length isn't long enough to do it in one stroke. I have to use another jacket to push the first jacket through. The punch withdraws and for the most part the partially drawn jacket is stuck in the die. I suspected the same thing would happen with drawning down .223 jackets.

If the lead in angle isn't critical then I can definitely open up the tolerance and change the die to a one sided die, which should help to pull the jacket off the punch.

It took me longer to do the drawing then I am use to. I have not done a drawing in +/- tolerancing in forever. Almost everything I do is in GD&T, which works for my job but most of the machinists I take to outside of the office prefer less complex call outs.

I'll post the revised drawing. I appreciate all the input, this has been extremely helpful.

[IllinoisCoyoteHunter]

Can't wait to see what you come up with. Simpler is better, in this case. My drawings are usually on a piece of scratch paper or the back of a napkin LOL.