[Splinter120704]

Is it possible to use regular drill bits on cnc machines? I'm cutting MDF board and was wondering if a 1/8' bit would work with that type of material?

[AssassinXCV]

Regular drill bits do not have the proper cutting edge on them. Drill bits can only cut downwards; not sideways, which is the type of tool required. Endmills have angled blades so that they can cut sidways, you can find them pretty cheap at around $7 each on ebay and other industrial supply stores.

[microcarve]

Assuming strictly hole drilling...

Using regular drill bits at the high speeds a router
has isn't a good idea...in general.

Most likely someone will pick a HSS bit and even though
it's high speed steel, it'll still get very dull, very
fast in an abrasive material like MDF. They're also too
long in most cases. It can even bend and become pretty dangerous.

Friction at the very high speed can cause burning and completely ruin
the bit in a few seconds.

I use common normal router bits whenever I can, They're easy
to get when you need them and are made for woods and high speed.

Carbide is the far better choice when it's available. Lasts
a lot longer.

If you're drilling holes, use a slow infeed and peck drilling.

If you mean using them as end mills....that question was already
answered....

Personally, I wouldn't put a drill bit in a router....though I've
seen it done a few times. If it breaks, it's a waist high bullet.
(But then, so is the router bit...)


John

[BuckNaked31]

I mounted a drill chuck with a 1/2" straight shank into a precision collet on a cheap Porter Cable router. I slow it way down with a speed control. Works great... now I know that I will eventually destroy the bearings in the router, but it's cheap and I have 4 of them in the shop. There isn't a lot of torque left when the router is going that slow for drilling, but it's a tradeoff either way. I will at some point pick up one of those SuperPID thingys and solve the torque issue, but for now it works fine. I was told by the guy at Think and Tinker that small diameter drill bits will drill holes just fine at high speeds, but I still slow it way down.

[jsheerin]

I've used 1/4" screw machine drills in my PC892 router spinning at 10k rpm. They're shorter than normal drills. I've never had a problem using them (balance, or anything like that). They do burn MDF when peck drilling - they're going too fast. But they do work. I've also used them to spot hole patterns on aluminum 0.01"-0.02" deep that I later drill by hand in my drill press. Hole patterns are fun on a router - the holes are dead on since the spindle is moving with no cutting load on it between holes.