Drilling tellurium copper, 145 copper

[Metalfixer]

Looking for the best method to drill 3/32" diameter hole thru 1.25 length of 3/8"
diameter copper.
I can use the lathe or vertical mill, but not sure on the type of drill or
coolant, or which machine to use, or feeds and speeds.
I have about 200 pieces to drill.
I searched and found many different methods, but I am posting here for other
suggestions.
I found out the hard way, copper is different to drill than steel. 3 broken
drills, no finished pieces.
Thanks,
Larry

 

[SwinnyGG]

Copper can be a bear- it would help to point out which exact alloy you're using.

Copper is difficult because it is extremely malleable- it will flow around tools if cutting pressures become extreme.

The most basic guidelines would be:

-use SHARP, bright tooling
-if you re-sharpen your tools make sure not to burn them
-LOTS of coolant is required. If your drills are getting warm to the touch, you need more coolant and/or slower feed. Copper will gum up quickly when working temperatures go up.
-split point 118 degree drills are probably your best starting point

You'll have to experiment with speeds and feeds. Because your hole size is so small, you need a lot of RPM.

 

[JNieman]

In addition to the SHARP tooling, I'll add that you should not use a tool on copper once it's been used on any other metal. IME, the wear, no matter how minute, affects the cutting geometry enough to ruin your performance in copper.

 

[Metalfixer]

Thank you both for your suggestions. The mill is CNC, would a peck-drill method
be advisable?
Thanks,
Larry

 

[John2025]

I'd be peck feeding every .030" and coming the whole way up out of the hole to clear chips. Flood coolant, too. 1.25" @ 3/32 diameter is tough in my book.

 

[dicer]

Tellurium ? Must be expensive stuff since its a very rare element.
Like all machining don't over do the surface speed, or push it too hard, if the highspeed breaks down too fast use carbide.

 

[cloa]

http://www.practicalmachinist.com/vb/general/110-copper-vs-145-copper-249857/

Better off asking at practical machinist.

http://www.eng-tips.com/threadminder.cfm?pid=1529

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