Drilling Holes in copper tube

[Martin Walsh 1Participant @martinwalsh1]

Hi

I'm making a small boiler 2 Inches dia

and I need to drill 3 holes 3/8 dia

what is the best way to do this. As I have

heard drilling holes in copper is a nightmare

Thanks

Best Wishes Martin

[Martin Walsh 1Participant @martinwalsh1]

[MadMikeParticipant @madmike]

I would suggest either a 3/8 dia hole saw/tank cutter or trepanning the holes.

[JasonBModerator @jasonb]

The stepped drills work quite well or use successive sizes of milling cutters say 1/4" drill then 5/16" and 3/8" milling cutters

[Neil WyattModerator @neilwyatt]

+1 for step drills.

Aldis often sell them at stupidly low prices, but always in metric sizes.

I don't think you'll find holesaws or trepanning cutters down to 3/8".

If you are brazing bushes in the holes, you can [probably get away with using a cone drill. Otherwise, drill undersize and file to a good fit on the bush.

Neil

[FMESParticipant @fmes]

These work very well Martin **LINK**

[John BaguleyParticipant @johnbaguley78655]

+2 for step drills. Centre drills work well as well.

John

[NilochParticipant @niloch]

+3; 'have drilled 84 x 12mm & 2 x 20mm holes in 10SWG copper with this

[Ian S CParticipant @iansc]

I have not got a photo of one. similar twist drills are sold for wood working, the end is ground so that the centre is a spur point, and the outer dia., is the point that cuts the hole, ideal for drilling sheet metal, no more triangular holes. It's easy enough to grind up an ordinary twist drill. Ian S C

[Roger WoollettParticipant @rogerwoollett53105]

Assuming that the holes are in the flat end plates of the boiler iether a step drill or a cone drill will work fine. The sort of drill Ian S C describes are sold as bullet drills. They also work fine.

Roger Woollett

[Ian S CParticipant @iansc]

I got taught to grind them when I was on an apprentice course at NAC(National Airways Corporation) This was before the days of Air New Zealand. Our airframe instructor learned of the drill type during WW2.

Ian S C

[Robert DoddsParticipant @robertdodds43397]

Martin,

Just producing three holes doesn't justify spending a lot of money but in another age I used to use "slow helix drills" to produce holes in the copper pipes for urinals. Burrs on the inside from break through were not encouraged (you get sprinkles down the trouser leg) and the slow helix reduces the tendency to grab the thin wall copper tube.
Not being sure if they were still produced I googled and then stumbled on this site from Tomsk University http://portal.tpu.ru:7777/SHARED/p/PRONINA/documents/files/f9.pdf
Its set out like a tutorial but theres lots of relevant info in it

Bob D

[Neil WyattModerator @neilwyatt]

These might help you get started:

**LINK**

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Martin Walsh 1 on 07/06/2014 13:50:40:

I'm making a small boiler 2 Inches dia

and I need to drill 3 holes 3/8 dia

what is the best way to do this.

.

I'm surprised to see that no-one has yet suggested

3/8" milling cutter [preferably 3-flute]

… which seems the obvious choice, to me.

MichaelG.

[julian atkinsParticipant @julianatkins58923]

i think you are all making things far too complicated!

i drilled 14 holes each end in my current boiler project for 3/8" dia tubes, opening up in steps to 23/64" dia then reaming 3/8" dia, using ordinary drills. i have drilled and reamed another 8 of same size for boiler bushes and a further 3 of 7/16" dia same method.

slow speed, and a bit of WD-40 sprayed on during same.

cheers,

julian

Edited By julian atkins on 11/06/2014 00:06:12

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