Grinding wheel direction of rotation

On some of the grinding wheels, I have seen an arrow marking the direction of rotation on the blotter. On the Dewalt 6" grinder that I have, the grinding wheel does not have the direction of rotation marked. Do all grinding wheels have a preferred direction of rotation? I ask because I removed the grinding wheels without noting how they were mounted at the factory.

Some wheels are are constructed in such a way that rotation is important so when you see a rotation pointer you should abide by it. Wheels with not such and most wheels can go one way or the other with no problem.

Also important that the wheel holding nut goes/turns in the tightening direction when you turn on the spindle/motor rotation. That a wheel have a blotter even if you have to make one, That you ring test ring-able wheels that you check the mounting hub for nicks and bugs, and that you check the wheel speed is at or under the spindle/motor speed.

Many abrasive belts have a direction arrow..that is very important to abide by because a failed glue joint can catch your work or your hand.

Machine feed lever have a desired direction that is going away from the push (so it/travel goes away from your hand).
Finding a machine that travel into your push may be wired wrong and so may go away from the internal safety stops so may break a machine rather that stop at limits.

Pretty sure that the OP is talking about the wheels for an angle grinder that have a threaded center. Yes they must rotate that way or come off. Unless you are using them as a Frisbee. Vitrified wheels, either way.

tdmidget said:

Pretty sure that the OP is talking about the wheels for an angle grinder that have a threaded center.....

Click to expand...

Actually, I was talking about the wheels for a bench grinder...