slitting and driftig copper question

[Pault17]

All,
I have a piece of 7/16 copper square rod that I wanted to use a sectio of for a finger guard for a dagger. My intention is to slit and drift the opening for the blade, but wasn't sure how to go about it.
should I anneal it first? pre-drill the slit and just drift it? split and solder two pieces together?

thanks,
paul

[johnptc]

i always like to start will drilling.

copper work hardens quickly so repeated heatings to soften it are in order if you work it cold.

[Fe-Wood]

I would work it cold because you have more time to get the layout right and feel how it works. I would also slit it as opposed to predrilling, just for the experiance. Drilling could be a little faster and accurate, but you also loose that material. I say a "little faster" because once you get it down without drilling, you should be about the same time for slitting when you take drill set up into account.

The window of workability hot or cold is narrow, so keep your eye on it for cracks as it work hardens...Anneal often and work from both sides.

Maybe do two at a time for the first one. You might try starting the slit cold then finish hot. Remember dull red is hot enough to work it.

Good Luck!

[johnptc]

i have a machining background.of course.....

either way keep it soft

[Frosty]

You can do it hot or cold and you'll really enjoy it.

The thing with copper alloys is how they work harden, it starts gradually, then bang it's HARD. It's possible to move it a LOT the first couple blows, then it diminishes fairly quickly to failure. Father used to say you take it as far as you could go with the first three "breakdowns," (he was a metal spinner) blows, bends, swagings, pressings, etc. then you have to be on your toes. My experience confirms this, you can hit it as hard as you can with whatever you can swing the first couple blows. Being reasonable of course, smacking 12ga copper wire with a 5lb sledge isn't going to yield very good results.

Anyway, pay attention and you'll notice when it starts to work harden. Bring it to almost bright red in the forge and go right back to the anvil with it. No point in quenching it and if you aren't fast enough to strike while the copper is hot, so what, it's soft, no big deal.

Use plenty of lube when drifting and if you're doing it hot work FAST or the copper will shrink and trap itself on the drift. If that happens don't panic, just hit it good and hard it should continue to drift on through. Do NOT play pitty pat with it! Hit it HARD to get max movement from those first couple blows or you run a real risk of cracking it.

Try it out on some scrap pieces first of course, so you have a personal feel for how far you can go with it.

Forging copper's fun, enjoy.

Frosty

Edited May 22, 2009 by Frosty

[Pault17]

thanks all for the guidance. as soon as I get the garage cleared out a little, I will try it out. I have about two or so feet of square bar to work with, so I can experiment a little

[Frosty]

Good deal, don't let it scare you, it's easy to work.

Frosty