When you need to replace a broken bit, or you want to load a special one for a CNC job, here is how to do it.
Step 0: bit is broken
Report the broken bit to a maintenance card, mentor, or metropolis-staff@
Place the toolholder in a vise
Make sure to grab it by the flats
Blow off chips
Loosen the collet nut
Use the collet nut spanner (in the endmills drawer in each mill cabinet)
Turn the collet nut counterclockwise, viewed from the bit end
If it’s tight, be careful not to mash your fingers when it lets go
Using a deadblow mallet on the spanner is ok if you need to
It may get stuck once more, after an initial loosening, just give it another twist with the spanner
Clean the taper
Clean the inside of the taper with air and a rag.
You don’t want any chips or excess coolant in there
Clean the collet and collet nut
Clean the collet and collet nut with air and a rag
You don’t want any chips or excess lubricant in there
Reinstall the collet and new bit
If you took the collet out of the collet nut, snap it back in by tilting it and pressing in
Insert the bit into the collet
Screw the assembly back onto the toolholder
Adjust the bit stickout
Finger-tighten the collet nut
How much stickout?
As a starting point, there should be 0 to 1 times the cutter diameter of shank exposed between the collet and the end of the flutes
You can use a little more stickout for special cases, but always at least two shank diameters in the collet
Tighten
Use the collet nut spanner to tighten the collet nut
The torque spec for ER32 collets is 100 ft-lb. So pretty much as tight as you can get it with the spanner