Resurfacer question.

[1745greg]

My boss recently bought a used Kwik Way 862 Front loading surface grinder. It have a CBN insert on it now instead of the grinding stones. The previous owner installed a speed controller to change the speed of the grinder motor to slow it down. It has a piece pf paper taped to it with readings of what mumber match the spindle rpm and it varies from 700 to 1200 rpm. Our question is why would you want to or need to change the spindle speed. We already have a DCM Tech resurfacer and it has only one speed which is around 1150 rpm. Why change spindle speed? Thanks.

[BrazilianZ28Camaro]

Material hardness.

The harder, the less rpm you want.

Spindle and head stability will be a factor in rpm selection also.

[wyrmrider]

can you change the feed also?

[1745greg]

Yes the table speed ca also be adjusted.

[needforspeed66gt]

You change spindle speed to set the necessary surface feet per minute SFM for the type of tooling/bits you are using. Grinding stones work best when turned fast - our machine will do 2400rpm, but when using CBN or PCD pucks I only spin it at 840rpm because that works out to the best SFM for that type of tooling.