Jacket Blanking Die - Attempt to make my own jacket blanking die

[Tikka308]

I'd like to make my own jackets! I have the time and equipment (at least most equipment) and, having been inspired by others on this forum, am looking forward to (hopefully) blanking, cupping/drawing then finally swaging bullets with my own dies.

I've read Corbin's book, the NRA book, the old Ted Smith PDF. By way of background, I run a youtube channel documenting my home shop machining and prototyping endeavors, http://youtube.com/saunixcomp. I own a set of Corbin dies (typical setup of squirt die, core seat and point form) which have been a great reference and starting point.

I purchased some 1" copper strips from Corbin. First step is to make ~0.95" blanks (which can then be cupped and drawn). The two examples I drew on were Corbin http://www.corbins.com/jmk-1-h.htm and and KTN http://castboolits.gunloads.com/show...=1#post1139178. The end goal is a 124 grain JHP 9mm. (As an aside, the 9mm jackets that Corbin sells max out at ~115 grain; anything heavier needs a longer jacket).

My hope was to make something I can use in my existing Corbin press (which, as mentioned below, seems inadequate for blanking). Once I have blanks, I can start making cupping and drawing dies.

The punch is annealed 41L40. I turned it down on my Emco V13 lathe and then used a file, then lapping compound to get to a decent finish and accurate diameter. Punch OD is 0.946"

The die is an unknown grade of steel (only piece of ~1.5" I had on hand). I expect to have to make these out of tool steel in the future. The Die ID is 0.950" I was told by a tool & die guy that 0.004 total clearance (2thou around the circumference) was appropriate for this application.

(FYI, in the attached photos, the die isn't finished; an ramp/angle & window needs cut which will allow the cut-blanks to fall out of the die into a holding bin)

The punch/die worked OK on a piece of 5thou brass shim stock but cannot come close to shearing the ~0.031" copper.

The KTN jacket blanking die and Corbin both have a slot that the stock feeds through (convenient!) which also serves as a self-aligning sidewall for the punch/die. My punch/die align OK in the Corbin due to that press' design. However, I was thinking about putting my punch/die in a 12 ton shop-press (which surely has enough power to sheer) but I don't have a way of retaining the punch alignment...

How does KTN cut that narrow slot? With the cutting edge of the die recessed inside the die, how would you sharpen or grind it?

[customcutter]

Wish I could help, but have no experience with what you are doing. My only concern is the die made of an unknown material. Is it hardened to the point that it could possibly shatter, if too much pressure is applied and everything isn't aligned properly.

BTW, that's a nice lathe, and the portable punch is awesome. Never saw anything like that.

Also last but certainly not least welcome to the site. Lots of info here and a great bunch of guys.

CC

[MOcaster]

Welcome tikka308.

I don't know anything about machining but would it be easier to make a draw die to size 9mm brass down to make a 9mm bullet? I make 40 cals out of 9mm brass and others make 30 cals out of it so I am sure it can be done. And probably cheaper and easier than making a blanking, a cupping and a drawing die. But more power to you that you know how to do that.

[customcutter]

Tikka,

I had a chance to see the thread with KTN's dies. He probably cut the slot with an arbor slitting saw, in a milling machine. They are available in different diameters and different thicknesses. I've used one to slot the "spring" in titanium liner lock folders that I used to make. Seems like the one I have is .020-.030. and 3" diameter.

here's a link to one at Grizzly, just happened to be the first one that popped up on "arbor slitting saw" google search.

http://www.grizzly.com/products/Slit...aw-Arbor/G1438

If your punch is angled and "sharp" I don't think you would have to worry about the die getting dull, if it is properly hardened. Also would take care of the alignment problem you said you were having.

[aaronraad]

Corbin uses the Mega-Mite (CSP-2) for manual jacket making as a minimum which has a fair bit more grunt than the S-Press (CSP-1).

Here are a couple of links with free information I found over the years that you might find useful for blanking and deep drawing:

Tooling By Design

Wise Tool

My first thought is integrating a die holder/pad



http://www.thefabricator.com/article...difficult-task

[midnight]

If you are looking to buy slotting/slitting saw blades, I get mine at Machine Shop Discount Supply http://www.msdiscount.com/columnar.a..._site=STARTOOL. Almost any diameter, thickness, & arbor size you may need. These along with the arbor from Grizzly should get you where you want to go.

Bob

[Tikka308]

Yes, I bet you are correct. Thinking it through - the slit should be cut first then the final ID dimension turned (or at least ground/polished)? I haven't used slitting saws much (have a hard time getting a good feed/speed on them) but I recall they can leave a burred finish. Or maybe I am over-reacting re: my concern about having a perfect, sharp inside corner where the punch meets the die (e.g. where the shearing happens).

[Cane_man]

Tikka, me likes my Tikka Hunters, got one in .243Win and .223Rem

[KTN]

How does KTN cut that narrow slot? With the cutting edge of the die recessed inside the die, how would you sharpen or grind
it?

With bandsaw and hacksaw, still can't afford to buy all tools and toys I need, so I must do with what I have. Cutting edge is as it is after slitting, so far it has worked.
Wellcome to the club of amateur swage tool machinists .


Kaj

[Tikka308]

KTN - Thanks for chiming in; I had hoped you'd see this thread. I also wanted to say 'thanks' for posting the information you have - it has, and no doubt will continue to, serve as a resourceful guide for all.

I will "slit" my die and see how it works and post the results. Thanks!

[Sitzme]

Corbin uses the Mega-Mite (CSP-2) for manual jacket making as a minimum which has a fair bit more grunt than the S-Press (CSP-1).

Here are a couple of links with free information I found over the years that you might find useful for blanking and deep drawing:

Tooling By Design

Wise Tool

My first thought is integrating a die holder/pad



http://www.thefabricator.com/article...difficult-task

For punching the blanks, I would use a die set, possibly used. Search eBay for "danly die" or "kick press" to get some hits. The set will provide a way of keeping things aligned and easy to swap in and out.

The die clearance depends on the material and thickness. Too much clearance and it will smear instead of shearing. Too little and forces go up, etc... I think that Machinery's Handbook covers it. Get a copy if you don't have one since it covers the world of machines and metal working. .002 seems like a lot for this application off the top of my head.

I would lean toward using a spring loaded metal stripper plate but the rubber method might be good to try first.

You can also slightly cup the punch so that you are not shearing the entire circumference at once. This will lower the force needed a lot and maybe allow the use of a manual or small air press. You can add all kinds of other goodies like a feeder and a weed cutter to chop the scrap but those are not needed until you start getting good blanks.

[Tikka308]

SUCCESS! Many thanks for the suggestions! Since I don't have a slitting saw, I took KTN's advice and used a bandsaw. The bandsaw blade was the perfect width for the material to slip through - a wonderful convenience.

I had some heartburn putting the part on the bandsaw - I have spent a bit of time getting 'er done just right on the lathe: perfect ID, a taper to let the blanks fall through... A feeling no doubt many know all too well.

Anyways, I cut the slot, did a little bit of (minimal) clean up with a small file, then used a 12 ton harbor freight shop press. Nervous was an understatement. One stroke... two strokes... then on the third 'pump' of the bottle jack, the material sheared! It was a wonderful sound and a very clean cut. Having never made a punch or die before, I'm beyond excited. I inspected the die, punch, etc - all looked go, so I figured "well let's see when it DOES fail!" - I ran through the attached photo strip of copper with no problems making ~16 blanks in only a few minutes! The punch actually worked better on the second half of the parts - I think it self-deburred a little.

Anyways, mission accomplished for now!!! Now it's on to cupping and drawing dies..

Thanks again folks.

[customcutter]

Glad it worked. I guess you'll be making bullet swaging dies next? Glad I know how to make jackets now if needed. Keep us posted on your progress with the drawing dies.

CC

[aaronraad]

Cha-ching x 16 well done!

[Tikka308]

Update - made two experimental 'cup' dies.

The blank is 0.95" diameter.

The first die (left) is 0.625"; that was too much of a reduction.

The second die (right) is a better 'first step' cupping die at 0.800". The second die matches the % reduction taken by KTN in his post (http://castboolits.gunloads.com/show...=1#post1138209). KTN took a 0.802" blank down to 0.675 (84.1%); that dictated the diameter of my second die attempt (0.95 down to 0.800 is 84.1%).

These experimental dies are 6061 aluminum; I can make a set in about 10 minutes so it's very convenient for experimenting. Something I am not doing (but think I may need to) is have a ring applying pressure to the perimeter of the jacket blank as it's being cupped; I believe this can prevent wrinkling. However, my 0.800" die didn't seem to show evidence of wrinkling, so we'll see.

Next step is to make some draw dies!

[plus1hdcp]

Looking real good and promising. I am following this thread with attention as I too would like to head down this path. Keep up the work and postings.

[Cane_man]

what can be used for copper sheeting/strips to make these if you dont want to buy them from corbin?

[customcutter]

Looks good. Are both the center punch and outer ring made out of 6061? Just wondering how well they are going to stand up to wear and pressure. I understand that you are just "proto-typing" for now.

[KTN]

Draw dies will iron off any wrinkling.
Are those punches straight? First cupping punch isn't any problem, but when jacket gets longer it starts to stick to punch. I made 2 degree taper to all punches.
Keeping blank and punch centered during draw is one problem to be solved.

Cane_man,

I'm using regular 0.031" copper and brass sheet, not any special deep draw grade, and so far it has worked fine.



Kaj

[Tikka308]

Cane_Man - reading through the various documents out there (Corbin manual, the NRA book, the old Ted Smith PDF, etc) there is a lot of discussion about grades of coppers, % zinc, etc. My impression was that a lot of that information and specifics applies to high production machines with custom dies that require consistent material specs for smooth operation and high-volume production. And, yes, some of the grades of copper can 'draw' better than others (but i'm not qualified to elaborate on that).

CustomCutter - Yes, right now both punch and die are 6061. I don't expect them to last very long at all - but still worth it given speed to machine (and the fact that I have lots of 6061 but very little steel on hand). I'll try cupping a bunch more to see if fatigue is apparent and will post photos either way.

KTN: Yes, punches are straight and Yes (!) they stick. Will be putting a taper on them ASAP After I am happy with the cup die size, I plan to make something similar to you (http://i122.photobucket.com/albums/o...n/IMG_3273.jpg) with the guide-bushings to aid in self-centering.

KTN - have you figured out how to punch the blank AND cup in the same die?