Spindle motors resonable options

[Jonathan]

It looks like you're only stopping the shaft of that spindle from moving axially with a grubscrew. Are you sure that's strong enough? Might be difficult to preload the bearings with that arrangement.

[wiatroda]

It looks like you're only stopping the shaft of that spindle from moving axially with a grubscrew. Are you sure that's strong enough? Might be difficult to preload the bearings with that arrangement.

Jonathan there is two grub screws and I used Truloc shaft retainer as well both on shaft collar and the top bearing. But the forces act on shaft up the spindle or sideways, but not down(trying to tear the shaft off from the spindle, if I can put it in this way). So far it worked well for quite few hours with no problems at all. If something changes I'll post info asap

[Web Goblin]

I have had a look at various bearings for making a high speed spindle and they cost a small fortune. I can get a set of 15000rpm bearings for £40 for 4 so I might go that way and give it a try.

Ian

[Lee Roberts]

I have had a look at various bearings for making a high speed spindle and they cost a small fortune. I can get a set of 15000rpm bearings for £40 for 4 so I might go that way and give it a try.

Ian

Did you build one in the end Goblin?

[Web Goblin]

Lee,
no I never did get one built. As per usual ended up working on something else and the idea got scrapped. At the moment I can t get enough time to finish my rebuild, but I have started thinking about a diy VMC build.
For some good news though I am off to Germany on Tuesday for the factory acceptance tests for the companies new £1M Laser. I cant wait to see it running.

[m_c]

Jonathan there is two grub screws and I used Truloc shaft retainer as well both on shaft collar and the top bearing. But the forces act on shaft up the spindle or sideways, but not down(trying to tear the shaft off from the spindle, if I can put it in this way). So far it worked well for quite few hours with no problems at all. If something changes I'll post info asap

A heavy sideways load will cause the shaft to pull down if the shaft isn't secured well enough.
How did you manage to preload the bearings if you only used grub screws?

[wiatroda]

How did you manage to preload the bearings if you only used grub screws?

The ER20 have threaded hole at the end (you may see it on web pics). I've just put another steel bush onto the shaft, put some load with screw pressing bearings towards each other. Truloc bounds within one hour, but I left it overnight. While I inserted a shaft seal on the coupling end, I left the other end without. The next day I filled spindle with oil leaving air gap that makes allowance for oil temperature expansion and then I put the seal on.
The only thing I would change is to replace the whole strait shaft chuck for tapered one. Of course I would then have to change the whole design: instead of unscrew chuck nut to replace tool I would replace the whole chuck with another one. That would make it a bit faster and there would be no need for Z axis resetting or at least I would know the offset. I'm not sure my lathe would handle bigger dia bars, definitely not my budget. It's quite exiting idea to try to produce this kind of spindle thou.