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Small drills

PostPosted: Mon Sep 16, 2013 8:08 pm
by andymay
Hello Pipemakers!!

One thing i always find a right pain is drilling the small holes in the chanter and keys for the pins, and likewise for riveting the springs on. I use 1mm as the size for these and the drills are prone to snapping even when great care is taken!

BUT!!

I have found these

http://www.ukdrills.com/product.php?catid=255

cobalt drill bits which seem MUCH better. Maybe they are much sharper? Maybe they stay sharper longer? Who knows, but they go through even nickel silver as though it was cheese!

Highly recommended - by me at least!

Cheers
Andy

(ps i've no connection to that company etc etc)

Re: Small drills

PostPosted: Tue Sep 17, 2013 11:07 am
by Richard Evans
Thanks Andy. I find the main problem is drilling brass, when the drill breaks through it can suddenly bite and break off. This is down to the cutting angles at the tip which are optimised for steel. Regrinding a 1mm drill is not something I would try!
I use releasing oil as a lubricant on holes deeper than about 1.5mm and find this is very effective in preventing breakages.
Cheers
Richard

Re: Small drills

PostPosted: Thu Sep 19, 2013 9:36 pm
by pipemakermike
The trick with brass is to replace the sharp cutting edge with a small stoned flat - tricky with small drills but when I was an apprentice it was common to have drills with stoned edges and kept just for brass.
Also, when turning it in the lathe I use a tool with no top rake - This for the hard brass that sprays off in small chips. For the malleable brasses and coppers I use a tool with some top rake.