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awshoot

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On the contrary, they are probably work-hardened at the original point of deformation. Try annealing some of a batch and see if they don't dent more akin to original primers.

I did some tests with annealed cups -- it isn't without some gotchas -- if you overheat them, they explode into glowing fragments all over your workbench and being so small, they heat fast. I did manage to get it to the point where I wouldn't overheat them, but I don't see any real difference between annealed and not annealed primers post firing -- see pics here:

 
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I designed the primer cup dies and started making them today. I ordered some .016 brass and it will only arrive next Saturday. I will test them on 12. Thou brass this weekend but it might not be usuable as an actual cup. The real primer cups are made with 0.03 brass and drawn so the sides are thinner and the base is thicker, not sure if these will work well or be risky for high pressure. Tests will confirm.
 

Lesliet

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Making me think about a hammer forge, there... I wonder how much force it takes to smack a pellet of brass hard enough to form a cup of the right thicknesses? Seems like if someone sold just the cups and anvils, they would sell enough to be worthwhile, at least unless/until the shortage abates. Not a hazmat item, so they could be shipped. You even get a built in limit to liability, since you have no control over how people load them and load cartridges with them.
 
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Progress report: I finished the die body finally. Its takes a long time to make tight tolerance parts, but its crucial for primer cups, the cup has to fit perfectly and cant have burrs. I cut a disk from .012 soft brass that i had lying around for gas checks and its a very clean disk, good because it will be even better with the thicker brass. Im getting tired and making dumb mistakes so will take a break. I have to turn the forming pin, thread it and cut the slot in the die body for the sheet to slide through. On a side note, the end cost of making your own primer cups and loading them is probably more than buying them already made. When you buy a low amounts of material it costs more. Thats a $0.04 piece of brass right there. But its good to have options in these hard times i guess. 0228211612_HDR.jpg

Ps. Awshoot i feel like im hijacking this thread, so the next time i post, it will be to show the end results good or bad.
 
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awshoot

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Progress report: I finished the die body finally. Its takes a long time to make tight tolerance parts, but its crucial for primer cups, the cup has to fit perfectly and cant have burrs. I cut a disk from .012 soft brass that i had lying around for gas checks and its a very clean disk, good because it will be even better with the thicker brass. Im getting tired and making dumb mistakes so will take a break. I have to turn the forming pin, thread it and cut the slot in the die body for the sheet to slide through. On a side note, the end cost of making your own primer cups and loading them is probably more than buying them already made. When you buy a low amounts of material it costs more. Thats a $0.04 piece of brass right there. But its good to have options in these hard times i guess. View attachment 834686

Ps. Awshoot i feel like im hijacking this thread, so the next time i post, it will be to show the end results good or bad.

Totally not hijacking -- post more! ;-)

Seriously, you have some skills and it's a pleasure to watch. Besides, I'm not the owner of the idea -- the aardvark dude is the grandaddy of all the threads.

Also, considering primers are what, 25-35 cents each on Gunbroker right now, 4 cents plus some partial penny of compound is an incredible bargain.
 
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I messed up during the initial design process and now I have to make another die body. This is very annoying, at least the punch is still good because I was able to remove the required amount of material to adjust for the design flaw. I also have to make a micro boring bar out of tool steel.
 
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awshoot

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I messed up during the initial design process and now I have to make another die body. This is very annoying, at least the punch is still good because I was able to remove the required amount of material to adjust for the design flaw. I also have to make a micro boring bar out of tool steel.

Keep going -- I can't wait to see it!
 
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All the parts are machined now. It first cuts a disk out of the material then pushes it throught the die to form the cup. The first part works 100%, the second part not so much.

The pressure on the pin is too great and instead of pushing it completely through the forming hole, the pin breaks through the center of the disk after forming a sort of funnel. This indicates to me that the transition is too hard and i have to work on smoothing it out. If you look at post 185, you can see a funnel shape at the front of the punch, this is the part i have to smooth out, it needs to be more gradual, ALOT more gradual. And i will buff it out as well as use some sort of wax lubricant to reduce friction.

It still may not work and in this case the forming process will have to be done in 2 stages, if that's the case i dont know, it may not be worth it. This is taking more R&D than expected but it is worth a try. At least for now, this die can be used as a great resizer for primer cups.
 
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We are above the typically recommended drawing ratio of 2, we are at 2.34 which is significantly higher. This is the blank to punch ratio. I am trying to cheat it as much as i can by increasing the draw radius and reducing the friction but this is not ideal by any means because everything has a cost. I guess i meant worth it for me, for now. I have a few other things also going on that need my attention. But i'm not done with this just yet.
 
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So good news/bad news! The bad news is that i may have to do more machining. The good news is that the thing works, all i did tonight was add a thin film of oil to the sheet and it formed a cup, i did not even increase the radius or buff the cone yet! So...its getting there. Problem is that cups walls are way to high and uneven. Is it stretching? I think so. Am i off in my calculations of the disk diameter? Is .180 id + 2(.119) not .418? The copper punctured disk is without the oil the brass cup is with the oil, they are next to a used commercial primer.
0302212106_HDR.jpg
I will obviously work on the radius and buff it to a mirror finish before thinking about more machining, but its encouraging.
 
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