Your WAG: how long would an aluminum taper crimp die last?

[Whiterabbit]

Imagine a taper crimp die made from aluminum for putting LIGHT crimps on brass casings. How long do you suppose it would be effective?

10 rounds?
100 rounds?
500 rounds?

[bedbugbilly]

I'm supposing it would all depend on the aluminum used? Somebody who is familiar with aluminum will probably come along.

My question would be why? A steel taper crimp die can be adjusted just as accurately as a hypothetical aluminum one to creat a "light" taper crimp on a brass casing. I taper crimp on 9mm as well as 38 Colt Short and Long at times and on 357 for my Handi-Rifle - all with cast. I have no problems adjusting a steel die to give a "light" taper crimp on any of them.

Personally . . . purchasing a steel taper crimp die that will last indefinitely versus an aluminum one that would be questionable wouldn't be a problem for me - I'd go for the steel every time. As Louis Sullivan said . . "form follows function". i.e. utilizing the best material for the job to be performed.

But . . if you have the equipment, material and skills to turn out an aluminum taper crimp die . . . I say "go for it" and see what happens, how it performs for you ad what the expected life of it would be. That's the only way you're going to know. And .. . . there's nothing wrong in trying something "a little different" . . . goes for anything in life. It might not work or you could discover new things!

[Whiterabbit]

My question would be why?


But . . if you have the equipment, material and skills to turn out an aluminum taper crimp die . . . I say "go for it" and see what happens, how it performs for you ad what the expected life of it would be. That's the only way you're going to know. And .. . . there's nothing wrong in trying something "a little different" . . . goes for anything in life. It might not work or you could discover new things!

The reason why is because noone makes a 20 ga magtech brass shell crimp die (that I know of?) and it's way easier to machine aluminum and brass than steel, and cheaper to buy a 3" long slug of 1" diameter aluminum than brass.

And since it's magtech 20ga brass, we aren't talking about 1000 rounds here, but batches of 25 to be reloaded a few times. Of course it's a non-starter if the die "wears out" after 15 rounds.

But you are right, probably only way to know is to try.

[Nueces]

I think the hardness and shape of the case neck would strongly determine how long an aluminum crimp die would last. That is, a work hardened, un-deburred, bell flared neck might even scrape aluminum.

[country gent]

Aluminum crimping brass will have a very short life span. What could be done easily if making it yourself is make an aluminum body with a steel crimp ring insert. This could be carried even farther if wanted to a steel sizing ring to neck size and the taper crimp insert for crimping along with a roll crimp insert just in case. Die would need to have bodys top cut and a threaded cap fitted to hold inserts in place, insert would need to fit the bored section with in .001-.002 but not a big deal. Something to consider.

[Ole Joe Clarke]

Making a taper crimp die from aluminum is a waste of time. If you are using it on brass, both materials are about the same hardness, which is very soft. Even the aircraft quality aluminum alloys (7000 series and such) are relatively soft, and machine very well. You can harden aluminum but at it's maximum hardness it is still soft when compared to steel. If aluminum would work all the manufactures would be using it because it machines so easily.

[Whiterabbit]

the question is how long would it work? Of course it will fail early. how early is early? 10 crimps? 100? 500?

RCBS's name would be mud if they made a crimp die that failed after 500 rounds. For me, that might be a 10 year supply.

Of course, such a guess would be just that. A guess. Thus, invoking the WAG name.

Do you suppose, with a light crimp on brass, an aluminum crimp die would fail after less than 10 rounds? how about 100?

[Frank46]

6061-t 0r 7075-t aircraft aluminum would work, or buy some 7/8x14 tpi threaded rod and make one out of that. No heat treating needed with the threaded rod when working with brass. I made a shorty neck die from the threaded rod because the rcbs neck die was sizing the necks too much for my 7.62x54r cases. So drilled,reamed and polished a hole in it and added a die lock ring. Have sized over 500 cases through it and no appreciable wear. Frank

[perotter]

One could anodize the die after it was machined. They say it would then be 60-70(Rockwell C).

[Ole Joe Clarke]

One could anodize the die after it was machined. They say it would then be 60-70(Rockwell C).

Anodizing is a coating process that only affects the surface for about .0002 deep, does not change the hardness. Besides, how you gonna machine it at 60-70 RC?

[hpdrifter]

Probably just long enough to get your hopes up.

[yovinny]

Could you make it in a 2-piece die ?
As in make the body aluminum, thread the top inside and add a steel insert with the crimp section.
2-piece dies are usually much easier to turn with basic lath tooling, because you dont need a reamer or a deep reach for any of the cuts.

Cheers, YV

[Whiterabbit]

I've been thinking about that. Might work nicely. That lets me do the bulk of the work with aluminum, and the only steel work is boring a piece of steel pipe. I'm not a threading expert and could really use aluminum to practice cutting the threads.

Although press fitting a steel insert into an aluminum body gives me the heebie jeebies, I can only imagine aluminum shavings, like seating a boolit in a brass not necked up enough.

I do find it a little embarrassing to go to my metal supplier and order "oh, an inch or so" of stock.

They tolerate it though cause I never haggle on price (as if those guys don't have to eat and pay bills too?) and buy brass and other stuff often.

[deltaenterprizes]

Scrap yards are your friend for small pieces or a bolt supply house.
grade 5 & 8 bolts are decent metal
i made a set of 45 ACP shotshell dies from grade 5 bolts and a shop made half reamer

[williamwaco]

Normal aluminum?

My guess is 100.

Again, why.

If you want a very light taper crimp, you can do that with your roll crimp seating die. That is exactly what I have done for 60 years. If you want a little heavier taper crimp ( only on a tapered case), you can use your sizing die.

Another thought. What metal does Lee use for the sprue plate on their 6 cavity molds. It is HARD!

[Pavogrande]

WR -- I like the two piece die solution -- several ways to do the deed -
or perhaps a steel ring held in by a threaded cap. -
Many years ago Neils Kvale of norma sketched a two piece sizing die lathe turned, then tack welded together --

wr always check with me for small bits of freebie stock -- I will never get it all used --

[Whiterabbit]

Good advice! It has been too long since we have been able to have a fine conversation. Sadly (actually joyfully), I have two children now ages 4 and 1, it is so hard to find the time to drive across town for social visits! But I will have to keep it in mind. I too have a cutoff bin that grows in size as I complete more and more "prime metal" projects.

[EDG]

Probably not more than 10 -15 rounds and maybe not 5.

I have dealt with machining aluminum for 45 years or so.
Even cold rolled steel might not last more that a couple hundred cases.

The Lee sprue plate is aluminum but it is hard anodized.
Hard anodizing is an integral layer of aluminum oxide about .002 thick. It is a CERAMIC. You can't even drill it or turn it with carbide tooling and have the tools last anytime at all. High speed steel tooling will not cut it at all.

Common sulfuric acid anodizing is used to protect ordinary architectural aluminum and consumer goods. It is about .0001 thick and will dull cutting tools but you can cut through it and remove it from the surface. It would not provide much protection from abrasive wear. Instead of 5 or 10 cases you might get 50 or a 100. Anodizing set up in many finishing shops is a minimum lot charge of $100.

[Pinsnscrews]

Contact CH4D, they offer a 20ga brass shotshell die set for the cowboy action crowd.

[Whiterabbit]

well, I just needed to man up. I made this from stainless steel.





The only bummer is that when I cut the final .004, I misjudged the adjustment and cut it probably .002" too big. D'oh! I guess I need to cut it all over again. I guess it's not so bad, it's just practice when threading. Practice cutting a threading tool, practice catching a thread.... =\

I guess I could also cut a rabbet and put inserts in there. Then I could make a sizer insert and a crimper insert at the same time. Might not be a bad idea.

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OR just set the load so it is .1" too high and compress the felt wad over the powder and crimp so there is basically zero case tension. I could do it like that too.

using brass shells for slugs is weird, given 20ga chamber dimensions.