ballen
Diamond
- Joined
- Sep 25, 2011
- Location
- Garbsen, Germany
I'm giving up on getting hold of a "factory original" inside grinding attachment for my cylindrical grinder. So am thinking through various ways of making my own.
The holder for the spindle or spindle motor is not difficult. I'll probably weld it out of some steel plate. This will mount on top of the grinder head, hinge up out of the way.
I could try to reproduce the original design. This had a 3000 rpm 400 Watt (1/2 HP) induction motor with a 250mm (10") diameter pulley driving a thin flat belt, then (for examples) spindles driven with 25mm (1") pulley to get 30,000 rpm.
Or I could use a more modern design: integrated motor and spindle unit with a VFD controlling the speed. One choice might be a 4,000 - 24,000 rpm spindle motor with (say) an ER16 or ER20 collet setup. Another way would be a Precise/Fischer spindle motor with an SRP6 collet setup (max 7.5mm ~ 5/16"). Or the same thing with a threaded arbor interface rather than collets.
For grinding shallow bores and tapers, I think any of these would work fine. But one of the things I want to be able to do is to clean up the short MT5 workhead taper on the grinder. This goes from 38 - 43mm over a bore depth L=100mm. So I could grind this with a 30 or 35mm wheel, or something a bit smaller. Question is, what's the minimum diameter of an arbor that goes this deep? About the longest I have seen in catalogs has L/D=6, which means something like 16mm diameter.
Has anyone here put together an internal grinding setup like this? How did you do it? Are you happy with the result? Can you grind a 38-43 mm diameter taper 100mm deep and get a mirror finish?
The holder for the spindle or spindle motor is not difficult. I'll probably weld it out of some steel plate. This will mount on top of the grinder head, hinge up out of the way.
I could try to reproduce the original design. This had a 3000 rpm 400 Watt (1/2 HP) induction motor with a 250mm (10") diameter pulley driving a thin flat belt, then (for examples) spindles driven with 25mm (1") pulley to get 30,000 rpm.
Or I could use a more modern design: integrated motor and spindle unit with a VFD controlling the speed. One choice might be a 4,000 - 24,000 rpm spindle motor with (say) an ER16 or ER20 collet setup. Another way would be a Precise/Fischer spindle motor with an SRP6 collet setup (max 7.5mm ~ 5/16"). Or the same thing with a threaded arbor interface rather than collets.
For grinding shallow bores and tapers, I think any of these would work fine. But one of the things I want to be able to do is to clean up the short MT5 workhead taper on the grinder. This goes from 38 - 43mm over a bore depth L=100mm. So I could grind this with a 30 or 35mm wheel, or something a bit smaller. Question is, what's the minimum diameter of an arbor that goes this deep? About the longest I have seen in catalogs has L/D=6, which means something like 16mm diameter.
Has anyone here put together an internal grinding setup like this? How did you do it? Are you happy with the result? Can you grind a 38-43 mm diameter taper 100mm deep and get a mirror finish?