Problem- Grinding graphite for microfinish

[jakskru]

Can anyone give some advice on how to grind graphite? We are using a type 11 cup grinding wheel (80 grit) in a vertical machine. As of right now we use a speed of 4000 rpm with a 60 in. feed. The problem is we have been trying to achieve a 32 micro finish, and can use some advice. Best we have done so far is 63 micro. We have also been trying to use a wirebrush, but can't seem to get it to put a consistent finish across the whole plate.

[neilw20]

Is the machine quite solid with no vibration?
It might require balancing.
If you run it at a lower speed, and wait quite a bit longer and get a better finish I would suspect out of balance causing the grinding shaft to deflect.

If belt driven, even the flapping of belts can cause jiggle and muck up the finish. When you mill something you make lots of little grooves in the surface.
When you grind things you are trying to knock the tops off, but if making new grooves in the process it will be like cutting the legs off a table to stop it wobbling.

[jakskru]

The machine is pretty solid, but the spindle is belt driven. After reading your reply, the first thing I am going to try is getting the tool shorter than it is now and try that out. Also, the plate is vacuum held to the table...do you think that not having a solid "edge" to help support the part may be contributing to the problem?