[Cobra92fs]

I've been searching for an answer to this question for a little while, and have found no clear results.

Before I get to the question at hand, I need to provide the appropriate background information.

At the shop I work in, we have three grinders using either aluminum oxide or ceramic blend wheels. Two of these are automatic surface grinders and the other is a CNC OD grinder. The two surface grinders have a fixed wheel speed, the CNC grinder will adjust its wheel speed to compensate for wheel diameter.

So now for the question. When is a grinding wheel spent? When is it time to change the grinding wheel? I am talking about changing the wheel because it is worn out as opposed to replacing it with a different style of wheel for a different application.

In my mind, with the types of wheels I described, I would do the following.

One the fixed wheel speed surface grinders, I would determine at what diameter the wheel begins to exhibit problems with obtaining the proper finish, burning, loading, etc..
On the CNC, with adjustable wheel speed, I would change this wheel once the maximum recommended wheel speed is reached.

Am I way off here? If so please let me know. I appreciate the help.

[Jim Dawson]

It sounds like you're doing it correctly. Pretty much the way I have always done it, as long as the wheel is doing the job why change it.

[Eldon_Joh]

The maximum wheel speed is inversely proportional to the square of the diameter. once the diameter is reduced to say, 7 inches instead of 8, you can run it at a factor of (8^2/7^2) faster.

Biggest problem you might run into is you will need to re-balance the wheel once a significant portion of it has been removed, and that's just due to differences in density, random variation in the wheel.

[Cobra92fs]

This is very much along the lines of my thinking. I really appreciate the information. If anyone has anything else to add, please feel free.