PROXXON 28858 micro twist drill
Proxxon 28858 has a 1.6 mm working diameter in the manufacturer drawing.
How to choose
Use the labeled working diameter to distinguish this pack from the smaller 28854. Confirm the supported shank and measure the intended hole separately.
Compatibility and limits
1.6-mm working diameter · match the model’s shaft to the holder
Questions before buying
Does the 1.6 mm number tell me which collet to buy?
It describes the cutting end. Match the holder to the shaft diameter in the Proxxon model documentation. The 28940 set lists its sizes separately.