[mactec54]

mactec54, That's true I missed that, you could use oil or another coolant though. I know with mine, there was no way regular tools would have worked the first time it was rebuilt. Years of being run hot in a wood shop production environment, had locked everything together to a crazy degree. In my case, even the heat and cool wouldn't work first time, as I tried every trick in the book. Eventually after heating and cooling a number of times over an hour or two; using wax each time to cool the joint, it came off. I have had to re-machine most of the spindle as a result to get it back in shape... In retrospect it wasn't worth the effort and I should have picked a better candidate for rebuilding!

If you had to use heat then you let it cool in the air and add penetrating oil once it has cooled

You really don't want to be heating anything though when you dealing with precision machined parts like these High speed spindles even though your one did look pretty rough to start with, some penetrating oils work if there is corrosion and fretting, normally without the heat, you use a bigger lever with the right wrench if they are stuck, I have used up to a 6 foot extension to get the leverage needed to get some undone

[ebno]

Hello everyone! I am currently also in the process of replacing the bearings of an HSD ES919 spindle from a Biesse Rover.
@Stepping3D Could you please give me some advice on the tightening torque for the top and bottom nuts and which thread locking fluid you used.
Did you balance the shaft after replacing the bearings?

Thank you very much in advance!
Kind regards, Norbert

[josesanto]

Can you send me an image of the bearing arrangement? I think the upper ones are mounted in line and the larger ones are mounted facing each other?