Drilling 1/8" holes in aluminum

Wondering if anyone has tried to drill 1/8" holes in aluminum. What feeds (RPM/plunge) are you using? What kind of drill bit? I just did a production job where I needed about 100 1/8" holes, and I snapped a 1/8" endmill mid way through :frowning:

Gwizard is giving me the following.
Aluminum= 6061
HSS twist drill
dia= .125
stick out = 1"
cut depth= .03
RPM= 5600
feed rate 12 IPM

You can see from this that your machine spindle may not slow down enough.

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I can get my spindle to go that slow, but I’m not sure what the torque requirements are like. I know my VFD doesn’t have a lot of torque at lower RPMs. If I can’t get the RPMs low enough, I should plunge faster to maintain the chipload, or should I just run a lighter pecking operation?

If you go to a 118 degree .125 carbide Tin or Tian coated drill you can increase speed to 20,000 and 43 IPM 2" stick out.


I’ve only got a TiN coated HSS bit right now so I guess I’m stuck going slow. I totally forgot gwizard can do drill feeds, thanks David!

Okay, I gave it a test run and the holes came out great at .03" doc, 5200RPM and 8ipm plunge. I also tried the same settings at 6ipm plunge and got a different chip. I’m not sure which is correct, so heres a picture, hopefully I can be enlightened :smile:

Which bit are you using? Also I think the chip on the left seems better.