Blanchard Grinding questions.

[TSkenny]

So I'm using a Blanchard grinder at work to get a set of .500in 19"x13" plates of A-36 HRS flat. Using a fairly course segmented wheel.

I broke the skin on both sides and they, of course, warped. The issue is with my tolerances. The plate needs to be flat within .020 (Datum A) and then the opposite side needs to be parrell to Datum A within .020. The plate thickness has to be .490 with a +/- of .020. Just taking the skin off brought them to within .005 of nominal. Ive tried bending them on a press to try and manipulate them, with no real luck. I used shims under the plates on the Magnetic table while adjusting the Voltage of the magnetism. Still having a lot of problems with it bending and flexing. Any suggestions?

[RICHARD ZASTROW]

How are the plates processed prior to grinding? Torch cut? sawed? waterjet? Stress relieved? sand blasted? All can either induce stress and cause distortion (Stress relief should reduce the problem).

Dick Z

[slowlearner]

Although I am not an expert on blanchard grinding, I do purchase quite a lot of it.
My supplier suggests a minimum of 1/16 grinding stock per side. I have been lucky
on occasion to order 1/2" material with minimal cleanup and get plates that are + 7/16 thick. I do understand saw cuts will cost more but warp less.