Replacement Spindle for benchtop milling machine

[Rabs]

Given that they were a perfectly adequate machine I'd repair the existing spindle.
On my benchtop mill I have a 10mm EasyChange Endmill holder and a 12mm EasyChange Endmill holder and use ER11 collet chucks on 10mm shanks and ER16 collet chucks on 12mm shanks as tool holders, this gives really quick tool changes and the collet chucks are cheap so it's affordable to have a rack full with tooling loaded.
Check the manufacturer's spec for the spindle bearings, I got rid of a DC motor that ran to 4000rpm and replaced it with a 3 Phase that runs to 7000 without issues.

- Nick

Hi Nick,
Thanks for replying. Have you got the same machine? I suspect that we must have slightly different setups. If I did as you do with tool->ER collet chuck with straight shank->easychange holder-> easychange chuck-> spindle the tool would be so far out that I wouldn't have much z travel left, not to mention losing a load of stiffness.

I like the idea of reusing the spindle but I'm really not sure that either it or I am up to it. In addition to the slop in the bearings there is also a load of runout (~0.1mm). I suspect that it was badly crashed at some point and then 'repaired'. The holes for the face pin spanner look like they've been badly abused. I have managed to get it apart but it was a complete pain so I'll need to machine a new one. I don't have any certainty that the spindle itself isn't damaged as well as the bearings.

I don't have an internal bearing pullers or a press to reassemble the spindle with new ones. I also don't have a huge amount of time to invest in the project and need the machine working fairly soon so I am looking for a more 'off the shelf' solution.