Hard spot in grinding wheel

[BobS]

I recently trued-up my wheel (done several times before) and then used the grading stone to go down to 1000 grit.  While grading the stone, I noticed that there was a small section of the stone that had a clear drag and a sound as it passed under the grading stone and I cold feel it with my fingers. 

I sharpened a few knives, but it was nothing like I have had in the past. 

Does anyone have any thoughts or recommendations?

[Jeff Farris]

Probably not the answer you're looking for, but try truing the wheel again.  These inconsistencies in the stone composition are usually only a few thousandths of an inch thick.