Well, I now have all the bits to build the spindle, so shall; have to crack on and see if I can get it to work.

The motor and controller arrived from China pretty quickly, as did the bearings and lovejoy couplings bought via Bearing Boys and ebay. The motor and controller are tiny, it's quite amazing to think that the motor is rated at 550 watts. This is a real advantage though, as it means that the complete spindle assembly will be a cylinder with an overall diameter of about 1.5". I'm toying with the idea of fitting the Z axis in between the Y axis rails, primarily so that I can (hopefully) gain some added stiffness by minimising offset loads from the cutter. The narrow diameter of this spindle is ideal for this, although it will mean offsetting the Y axis leadscrew to one side (although I can't see this being an issue).

I'm going to try and machine up a small spigot to fit into the end of the chuck shaft (it's internally threaded 10mm) to couple to the lovejoy connector, as I need to get the shaft size down to something similar to that of the motor (the motor shaft is 4mm). Luckily there is a small counterbore in the chuck shaft, just above the start of the threaded section, that seems to be very concentric to the shaft OD (I can't measure any run-out with a DTI). I'm hoping that I can use this to align my shaft adapter, although if it's a thou or two out it won't really matter, as the coupling will cope with up to about 15 thou of misalignment.

It looks like this evening will be spent boring lumps of alloy bar and machining up the shaft adapter. I'll post pictures as soon as it's done.

Jeremy