[Bob La Londe]

I am not sure if this would work for you, but on a freinds small mill he put a water cooled spindle chinese brand and made a r8 collet weld on it so when he wants high speed he mounts it into the machine. not the cleanest option but worked

I thought about something like that, but my KMB1 is Kwik 200 rather than R8. I would either have to clamp a bracket to the quill which would reduce the travel of the quill or I would have to mount a bracket to a tool holder which would require I keep the spindle brakes on. I don't totally trust the spindle brakes. I sometimes spin against the brake when removing a particularly sticky tool holder. I think by building a whole second Z axis I'll be able to have a little more working flexibility. I will be able to retract the 24K spindle completely out of the work area when its not in use, also once I make a few test cuts I'll have the offset of the two spindles so I can work on a work piece that's within their overlapping work envelopes with either spindle. I actually already have the sliding Z rail assembly for the Z-2. I just put new linear rails in it this afternoon. The old ones were pretty rough.

P.S. At one point during the retrofit I actually considered totally removing the head from the mill and building a high speed head for it. If I had a second KMB1 I might do that.