platen grinding?

Since I hollow grind most of the time it's seldom that I put the platen of my grinder. However, when I do occationally I will get small hollows in the flat grind. Is this due to belt tension or something else? Let me know if you have a cure because it's frustrating when I have to remove these from a nearly finished blade.

Gary

NOT KNOWING THE TYPE BELT OR GRIT, I WOULD GUESS YOUR PLATEN IS NOT TRUE, FLAT. TRY GLUING APIECE OF 1/4 PHENOLIC TO THE PLATEN OR SOME OF THAT HIGH HEAT GLASS, THATS DARN EXPENSIVE. IS YOUR PLATEN BENDING, WHEN YOU APPLY PRESSURE. YOU MIGHT NEED TO RIG A BRACE TO KEEP IT FROM BENDING. THESE ARE THINGS I HAVE DONE TO CURE THE PROBLEM, YOU HAVE MENTIONED.
KEN (WWJD)

The platen appears to be solid enough not to bend any. I'll try glueing a piece of mycarta to it and see if that will make any difference.

Thanks,

Gary

Gary,
When your belt starts getting dull, it seems to leave grooves because it is loading up.
Try changing belts when it happens next time.
I hope it helps.

The best way to true up a platten is to turn it over and sand it on a flat plate by hand. You can see every ripple in it.
A surface grinder is exact.
I'v even heard of people turning the belt over and sanding it down in place, but I don't recommend that one.
It may just be a dull belt.

Thanks Geno,

I'll give it a try.

Gary