I am building a cnc mill and using a Taig spindle (coupled to a 300 watt brushless motor). The spindle is ER16 rated at 10,000 rpm. The largest collet is 3/8".

I have several 45 and 60 degree brand new Weldon dovetail cutters that would be nice to use in the mill for making various adapters, but they have a 1/2" shank.

I am pretty sure they are hardened, so turning them down to fit the 3/8" ER16 collet is less than desirable. Is there some sort of 1/2" endmill holder accessory that mounts on the nose threads of the ER16 spindle? I did not see such a thing on the Taig website.

Would you even attempt running this type of dovetail cutter with the Taig spindle? The mill itself has 300 watt brushless motors, ground ballscrews, and THK linear bearing box ways. About 60,000 pounds/inch rigidity.