Well, I decided I needed to upgrade my CNC machine (replace almost everything from the original machine I purchased). having already upgraded the controller, spoil board, spoil board mounting and spindle it's time to look at the axes ....
First I got myself an 80mm diameter er20 ceramic bearing 2.2KW water cooled spindle with labyrinth seals to replace the cheap 65mm 1.5Kw er 11.
To fit the 80mm spindle I had to make a new mounting plate. This included experimenting chamfering and threading. I settled on 0.3mm chamfers at 45 degrees and experimented with thread milling. The result I think is ok: (full discloser I purchased tooling plate so the top and bottom surfaces were already machined flat, but all the other surfaces got machined.
I have ordered 4 nema 23 closed loop steppers (3NM - about twice the holding torque of the original open loop steppers the machine came with), which will entail replacing most of the wiring loom, removing the existing open loop motor drivers, removing the motors, some software config of the new closed loop drivers and some changes to the controller wiring. The original divers have no error output pin so the controller has no idea if a stepper has an issue. The new drivers include error output pins so they will need to be connected to the controller. (stock jpeg from the ebay listing, I'm still waiting for delivery)
I have also replaced the standard 'deep' groove (6001 series) bearings inside the bk12 bearing housings with angular contact bearings (7001 series) as per this you tube video:
I also noticed that all the bearing blocks were attached to the machine with m5 bolts despite the blocks being designed for m6, So I plan to replace those bolts and find a way to make new threads in the machine housings.
The nema 23 motors are also designed for m5 bolts but the machine uses m4 (on avery axis except Z), again I don't know why fox alien decided to use one size smaller bolts on everything that drives the axes so I will have to machine new back end plates/motor mounts too.
After these upgrades and fixes the only original parts of the machine left will be the frame, axe and the metal case the electronics came in.
It's so nice to have a cnc machine so I can make parts to upgrade my cnc machine...