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DIY cartridge crimping tool

Fred

Fred

Well-Known Member
Hi there.
I made this tool up from scrap materials in my workshop. It is intended to crimp a groove on cases from 20 - 50mm although it will accommodate larger ones at a pinch. It works like one of those little copper pipe cutters but instead of a blade it has a roller formed with the shape of the groove required. I will need to make several rollers to suit different sizes of grooves and this requires a lathe but otherwise construction is easy. It cannot be used freehand, because it will wander and make a mess of the cartridge so in use, it is clamped down to my workbench. The rim of the cartridge must be supported on wooden blocks so that the axis is parallel with the bench and a depth stop provided. The wing nut is progressively tightened, forcing the roller into the groove whilst the cartridge is rotated by hand.
crinping tool.jpg
You can see that it made a nice job of a 40mm bofors with a breakup projectile.

I hope someone finds this useful.
Fred
 
Nice work Fred, a few of us would like one of those I'm sure.

Dave.
 
Hi Fred,
Looks perfect. How much would you charge to make one? Not everyone has access to a workshop.
Cheers
Gary
 
Thats a really nice looking and well built tool, i am sure we alll have need of one of those for one round or another and easy to switch wheel for different style crimps.
Best regards Weasel.
 
Full marks,well done,just shows what a bit of ingenuity can achieve,all praise is well justified,
regards,
Don,
 
Thanks for the positive comments. I hope to crimp a few more cases in the coming weeks and if Im happy with the design I may be able to provide drawings, instructions or other assistance making it. One change I have already noted is that the wing nut doesn't offer enough leverage to tighten the tool so this will be replaced with a conventional nut.

Fred
 
Your crimper is very nice!

There are a couple of other options if you only have a few cartridges to do. You can use a regular pipe cutter, but dull the cutting wheel by running the cutter around a hard steel shaft, so that the hard steel dulls the sharp edge on the cutter or if you have access to a lathe, just make a new wheel to go in your pipe cutter.

The cheapest way to do a simple one is to get some copper wire of the radius you want the groove to be, then wrap the wire around the outside of the cartridge case where you want the crimp to be, and then put it in a vise and tighten the vise. It will force the cartridge case into the groove and the copper will not mark the case, then just loosen the vise, rotate the case a little and tighten again. Repeat till the groove is complete around the case.
 
Very nice,I wonder if you machined sections off the wheel would it work for 'staggered' crimps for example 20mm Hispano ect?

Tony
 
Tony - I think the circumference of the roller would have to exactly match the circumference of the cartridge for that to work. In theory it would work but I wouldn't want to ruin cases trying!
I assume that intermittent crimps are applied with some sort of collet in the factory.

Fred
 
Very good idea with the staggared crimps. I've wanted to do ogives for 40mm LV and HV grenades, and this might just work. GROG
 
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