312. NEVER use brad point bits...for this

[Make Things]

Hello:
Two things that would help when you drill holes:
1) clamp the work piece so it doesn't move.
2) put a piece of scrap under the work piece so there is less breakout.
Plus the melted chip suggest the drill bit was turning too fast. Cut slower or add a coolant.
Carl.

Hello, thanks for responding.
1) yep, that helps with all drilling, but I don't think it's important in this scenario. Or, at least I don't think it would help.
2) Actually, I would definitely not suggest doing this. When you drill, you build up heat and you want a clean cut out on the bottom. Because plastic cracks with pressure, putting pressure on the outward side actually cracks the plastic as you push down. I've had far less cracking when done this way.

The lesson I've been telling everyone when they buy a drill press is to use the slowest speed...all the time. Metal, wood, plastic, there is NEVER a good reason to use a bit fast. I have a cheap 150 piece set of brad point bits I bought 20 years ago for $30 that I still use. I do not throw away drill bits because you do very little damage to them if you're running slow and cool. Twist bits with metal is a different story, but brad point bits will last you many many many years if you abide by this rule.

Here's a video I made a few years ago showing my testing fast vs slow with the drill press: