Grindmaster 4000

[toko]

I recently bought a second hand Grindmaster 4000 which is quite fine.
Taking the shaft out I found that it is quite flat (no shoulder and flange at all).
So tightening the stone with nut will expose all force to nylon bushing and further to machine body.
The maschine works however. Do you have new thicker shouldered shaft and respective bushings as spare part?

Thanks