Drilling copper

[mcr]

How to anybody?

[Bernd]

Try with regular milk.

Bernd

Edited: I'm not being funny here. Guy Lautard said this in one of his Beside Readers. I guess it really works. I've never tried it.

[andyf]

Received wisdom (from late lamented engineer father-in-law) is to dub off the cutting edges of the drill bit, so they have zero or even positive rake. I suppose that's akin to using 0 or positive rake for turning brass. If it's thin sheet, it would do no harm to increase the angle on the end of the drill from the standard 118 degrees to 150 degrees or so, to give it a chance to start making a proper hole before it comes out the other side and starts yanking itself through.

Andy

[chuck foster]

im watching this thread cause i have never been able to drill a round hole in copper. 
the drill always grabs and tears it way through leaving a egg shaped or octagonal hole.

so lets hear the ideas that will make copper drilling easier.

chuck 

[Bernd]

Use a sheet metal drill. It almost looks like an end mill except it has a point sticking out in the middle. Something a kin to a wood spade drill.

Bernd

[Bluechip]

mcr

Holes in copper what. Bar or sheet? Size?

I've poked a good few holes in alum. sheet in my time, not too dissimilar from copper.

Once I saw large (30mm) ish holes put in copper anodes with a spade drill using milk as Bernd said. If it's sheet, use a chassis punch or holesaw.
If they are small holes 1/8 - 1/2" ish you might try a carpenters  lip & spur drill. Cheapish, the lips will scribe the outer, and the spike in the middle will locate.
I have used 'em on ally sheet to stop the '?-agon' effect. Useless for deep holes I suspect. Never tried that.

Also need a backing material to stop chewing up on breakthrough.

http://www.axminster.co.uk/product-Axminster-Lip-and-Spur-Bit-20964.htm

Dave BC

[bogstandard]

MCR,

As previously stated, cows milk is a good cutting lubricant, and try to get the full cream variety. It is something in the fat content that does the magic deed.
 
Tallow is the correct lube, but they are very difficult to catch at this time of year. Their legs fall off in the summer months, so they can't land until they grow back again, which is usually around Christmas time. Processed lard (shortening) is a good substitute.

I have had great success with both bullet tipped twist drills for the smaller holes, and Aldi 'special buy' cone drills for the larger stuff. Trepanning works for really big stuff.

You need that guiding centre to stop it jumping about and making those 'triangular' shaped holes.


Bogs

[malcolmt]

Hi Bog's
I liked this : -     

"Tallow is the correct lube, but they are very difficult to catch at this time of year. Their legs fall off in the summer months, so they can't land until they grow back again, which is usually around Christmas time"

I have found that living in the country, it is acceptable to shoot your own Tallow and it is regularly available from dodgy looking chaps even out of season.

                

Kind regards

Malcolm

[bogstandard]

Hi Malcolm,

Long time no see or hear.

We all need a bit of humour now and again, even us old grumpy pharts.


Bogs

[usn ret]

For thin sheet of just about anything "Step Drills" mfg by Irwin produce adequate results. Sizes range 1/8 to 1 1/4". The drills are sold in sets of 3 ranges ie. 1/8 to 1/2" , 3/16 to 3/4" and 3/8 to 1 1/4".  I have used the to drill holes in thin sheets of alum, steel and stainless with acceptable results. On the east side of the pond they may be called cone drills or something else a bit odd. If you Google "step drills" it will produce sources for aforementioned bit..  The Irwin site produces the best results "Unibit step drills.  "Time for
Cliff