Thread: Can I use standard drill bits in CNC collets?

You can use normal drill bits but you will need the appropriate size collet, so if you want to do anything other than 6mm I would suggest getting er11 collet set which will give the range from 1mm to 7mm

Rick

Originally Posted by warrick

You can use normal drill bits but you will need the appropriate size collet, so if you want to do anything other than 6mm I would suggest getting er11 collet set which will give the range from 1mm to 7mm

Rick

Thanks Rick, great to know!

The joy of a collet chuck is that you can fit standard collets within a range of bore sizes. The ER range have a fairly wide grip range compared to many other styles, so there are fewer sizes in a set, just use the collet that is at the size or slightly (<0.5mm) larger than the bit shank.

Beware however of spindle speeds. The spindle supplied is intended for routing, where the spindle operates typically 10 times faster than a drill bit of similar size. The listing claims a spindle RPM range of 0-24K, but it is most likely inefficient and ineffective below about 8K. Typical drilling speeds for 3-5mm are in the order of 2-3K, faster will burn up bits quickly and burn the holes rather than drill them. I suspect the spindle motor may not be happy at the lower speeds.

You can buy drilling router bits in the 3mm and 5mm size as commercial CNC operators use them for screw holes and shelf pin holes when prepping cabinet sides etc in melamine. These have straight shanks rather than stepping down from a larger shank to the bit diameter, but I doubt that you would get more than about 25mm cutting depth from them. I also doubt that you will get 45 mm from a standard drill bit either at those sizes, and the machine may not have the height to use long series drill bits.

Regardless of the bits you use or the the motor that drives them, you will need to use a 'peck' process rather than a plunge process to continuously clear the shavings from the bit.

Hope these concepts help you plan your project.

I'd also check to make sure your machine is rigid enough.] and bit is sharp.

When attempting to do deep holes using my x-carve, unless I was careful the bit would grab the edge of the hole and rattle around a bit, damaging the hole and sometimes move the work.

Get yourself some carbide drills and you can happily run it at 10k rpm.
45mm depth is not going to happen in 3mm (it can, but you'll be past the end of the flutes so you'll have to retract most of the way to clear the chips out during pecking), 5mm you should just squeeze in a standard jobber length bit.