Rifle Cartridge Pens?

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I have made my first cartridge case pen. Sorry no photo yet.

The .308 case that I used has a slightly domed primer end.
Therefore, the top (turned out of bloodwood) does not interface with the cartridge case as cleanly as I wood like (no centerband - just wood against brass).

Do those of you who have done this before mill the brass flat, undercut the wood, or have some other trick that I haven't thought of?
 
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Sylvanite

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The case head (what the primer end is called) should be flat. I've never seen one that is convex. If the upper barrel doesn't mate well to the case head, I'd suspect some other cause, such as:
a burr around the hole drilled for the tube,
a tube that isn't flush or below, or
excess glue.

A burr can be removed with a chamfer tool (or a countersink). A protruding tube can be filed (or honed) down. Excess glue can be removed with a knife.

If I actually ran across the problem you describe, I think I'd undercut the upper barrel.

Good luck,
Eric
 
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My face is red.[:I]
There was a little bit of excess glue, but that isn't the problem.
I squared the blank with a pen mill, but I must have accidently touched that end while sanding.
The wood is convex.
Sometimes the biggest help in solving a problem is knowing what isn't a problem. When I stopped blaming the brass, I was able to quickly see the problem.

Thanks for your help!
 

Sylvanite

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One other problem that is easy to run into, is overmilling the blank. a 7mm pen mill will tend to cut the wood down a trifle more than the brass tube. It is just enough to feel, and to be visible when the parts are assembled.

Your problem may be different, but I'd try to solve it the same way I treat an overmilled blank. I keep a diamond-stone handy for final truing of blank ends before assembly. I lay the stone on a bench, and being careful to keep the blank square and perpendicular to the surface, I swipe it back and forth just enough to remove any excess brass or glue (from the finish). I used to use a piece of sandpaper on a flat surface, but I found that the diamond stone is agressive on brass, but not so on wood or acrylic. As a result, I am less likely to wind up with an out-of-square end.

I hope that helps,
Eric
 
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Eric,
Because I used a .308 cartridge with a bullet nip, I found that I had to leave the tube sticking out the back about 1/4" to be able to put the transmission in far enough for it to be secure. I set the tube in the wood blank back far enough so that a 1/4" section of empty 7mm hole would be at the transmission end to slip over the part of the tube that extends from the back of the case.

So the diamond-stone idea wouldn't help in this case.
But it is a great idea and I will use it in the future.
Thank you
 

Sylvanite

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Yes, I make bullet-nib 308 cartridge pens the same way (http://littlerivercrafts.home.mindspring.com/Supplies/308Instructions.pdf). The tube has to protrude from the case head a ways to hold the transmission securely. The tube in the upper barrel needs to be recessed accordingly.

If the problem is that the end of the upper barrel got rounded slighly, you could solve that either by milling it flat again, or sanding it flat (or rubbing it on a diamond stone). Just take care to keep the end square.

Good luck,
Eric
 
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