Drilling 1/2" Aluminum

[bstern]

I am making a mount for my new aggregate out of 1/2" aluminum.

I need to drill 8mm holes in the plate.
What type bit would work best?
What speeds and feed rate?

I usually only work with Melamine so this is kind of out of my realm.

Thanks,
Bob

[blackhawk]

If you have a spindle, you can use a regular metal cutting drill bit. I would use 2000-3000 rpm with a .3 IPS feed rate. The feed rate is conservative, but is a good place to start. If you have Aspire, they have a peck drilling routine that would be good to use.

If you are using a router, I would use a 5/16" upcut 2 flute endmill for metal, which is only .003" smaller than 8mm. The router can't turn slow enough for a drill bit. I would turn the router down as slow as possible on the RPM and feed it in at .2 IPS as a starting point.

[John David]

if you need exact size hole I have done a pocket with a 1/4 bit seems to work great

[taylor]

how about using the shopbot to make dimples in the aluminum where the holes need to be and then drill them out with a drill press.