the less tool stickout, the better! Basically, you want to use as short an end mill as practical for the job at hand, and grip it as close to the flutes as possible to minimize tool deflection, bending, chatter. Okay, we have the collet in the mill, now we're ready to mount the actual cutter!īut first, a quick note on *where* to grip on the cutter with the collet! Our Jet mill here at menlo park techshop doesn't use one and the collet will pop right in at any rotation, but our older mills do, and will only slide all the way in when it's lined up correctly.ĭon't panic if it doesn't want to slide all the way in, just rotate it around until it does! Some mills use a protruding pin in the spindle bore to key into the slot on the side of the collet to keep it from rotating inside it's taper, so if it doesn't want to pop all the way in, try spinning it around until it easily slides in all the way. Don't crank it all the way down yet, or you won't be able to get the cutter in! Reach up with the other (right, in my case) hand, and spin the drawbar threads down a few turns into the collet, capturing it and preventing it from falling out. Okay, now it's clean, pop that collet up into the spindle, and hold it there with one hand (I use my left to hold it there, I find it's an easier reach for the drawbar in the next step this way).

Not a good thing when you're trying to mill an accurate slot, etc!

If you find any, clean it up! A chip stuck on the collet taper when it tightens up will throw it off to one side. It should be clean of any debris, coolant sludge, etc. Up next, mounting that collet into the mill spindle! But first, stick a finger up into the tapered bore it seats in, and feel around for any chips.

Long drill bits for vertical mills