How to drill a copper block?

A

Alberto-sp

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Hello. I have to make a long hole on a copper block. 90mm long, and 6mm diameter. The last attemp ended with the dril bit broken into the block. Very nice :) (it was with a 4mm drill bit)

I think part of the problem was that I was using to many RPM. Although copper is soft, is very "sticky" so that could be part of the problem. cutting oil? cutting fluid? Any advice?

Thank you!

Best regards
 
I've read that milk is great for cutting copper. That's a really long hole length to drill diameter - start off with a short drill, then work up to the drill length you need. Make sure you withdraw the drill every 5-6mm to stop the chips packing in the hole. I couldn't advise you on rpm, I'd probably start off slow and work up from there.
 
I find with any real thickness drilling copper, I basically have to “peck” drill (ie: in/out in/out in/out etc) or it gums up around the bit and either jams and/or snaps the bit.

Even if its thin, I find its nearly impossible to keep the bit from grabbing as it first breaks through. Strong clamping and a fine control on the drill press essential for me, especially if it breaks through and I’m not expecting it.

I find copper just too super gummy and soft to do much of anything with besides cutting copper pipes with the pipe tube cutter.

I’m sure it can be worked, but its outside my wheelhouse of abilities.
 
The Machinist Bedside Reader suggest using milk as the cutting fluid for copper. I have not personally tried it, just passing on something I read.
 
I have drilled lots of tiny holes in copper on my lathe. I got a little drill chuck on a sliding shaft and spring. Use my fingers to peck drill, lots of tiny pecks. had good look just barely blunting the drill with a stone, keeps it from snatching so bad. I always used WD40 but I have heard of milk.

edit found one like this but a lot cheaper

Hhip Sensitive Hand Drill Feed & 1/8" Keyless Drill Chuck 3700-5000 | Zoro

Order Hhip Sensitive Hand Drill Feed & 1/8" Keyless Drill Chuck, 3700-5000 at Zoro.com. Great prices & free shipping on orders over $50 when you sign in or sign up for an account.
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Reduce the rake on the drill bit so it cannot get much of a bite.

Smaller bite means thinner chips, less power required but more pecks

Sent from my SM-G781V using Tapatalk
 
I don't think I'd want to use milk to drill copper in my garage. I can see it going all over and unlike oil or cutting fluids, it will go rancid if you don't clean every drop.

It may work, but I can't see myself using it......
 
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