How fast is too fast on Z for drilling...

[harryball]

I'm predrilling holes in 1/2" ACX plywood (pine) with a 1/8" bit. The bit is a standard straight 2 flute bit and I can't imagine at 12,000 RPM that the wood offers any serious resistance. I'm running an HSD spindle and currently run at 1 ips for one plunge.

From the experience gallery would I have a problem running at 2 ips, or 3 ips for the Z plunge? Should I peck drill? I only ask because I spend a fair amount of time predrilling. I don't want to damage the spindle, but I'd like to run as fast as possible.

I know an air drill and second Z would be best for my projects... I'm saving up for that.

Robert

[Brady Watson]

Robert,
You should be fine running 2 IPS, you can save a considerable amount of time by keeping your safe Z around .25" or less. 12k RPM sounds about right, listen for stalling & burning. Adjust RPM accordingly. I don't think you need to peck, as this would just slow things down. I wouldn't go over 2 IPS with a 1:1 geared Alpha Z motor.

-B

[harryball]

Thanks! I'm running safe Z at .25" and jogging at 20 ips. I'm slowly tweaking these files faster and faster. I'll be running this revision shortly to see what happens.

Robert