I have a LPKF 91S (from 1995), I use it for several boards a week. The spindle of the machine starts having problems with irregular speeds and stalling, breaking the mill. I can not get the spindle open to attempt repair.

A new spindle from LPKF costs €825. In 2018 the price was €200 but availability of these old parts made the price go up. The spindle size is 32mm. Does anyone know of a replacement?

I can get a refurbished S63.
What are the alternatives? I would like to make tracks of 4 mil but would also like to be able to mill alu or silver.