10-3mm Adapter for ER collet
Pretty simple, this is just a D10mm rod with a D2.9mm hole drilled into it 30mm deep (minimum). Plus a couple of M2 holes for grub screws. Will allow me to fit a 3mm drill bit, and hold in a 10mm ER20 collet. So I can easily swap over, and have the same length as my usual 100mm mill end.