Centerless grinding

[Bluesman]

OK I am new to this process, But I am lewarning right now i have a problem I got a finish that as shadows in it the micro is great and the roundness is too, I can not figure out where these shadows are coming from Is this what chatter looks like on a centerless grinder?


Bluesman

[RICHARD ZASTROW]

Chatter can distort reflection in smooth surfaces that look cloudy or shadowy and can't even be measured. Are you sure you aren't burning the workpiece?

[Bluesman]

Originally Posted by RICHARD ZASTROW Chatter can distort reflection in smooth surfaces that look cloudy or shadowy and can't even be measured. Are you sure you aren't burning the workpiece?

They are shadows just a tad darker than the finish and they spiral around the whole part. They come and go. If I had to guess I would say it looks like chatter. But I am a CNC schmoe and have got just 4 weeks in these grinders

Bluesman

[RICHARD ZASTROW]

Sounds like "barber pole". Can be caused by dull wheel (not dressed), feeding thru too fast or wheel not dressed straight.

[dandy]

It has been a long time since I ran one of those. But Cincinnatti had a green colored book that had a lot of formulas in in based on size of the wheel part size and regulating wheel size. It gave what angle to dress the regulating wheel so on. Also on if you were thru feeding or in feeding. Following their guidelines eliminated a lot of problems

[pstewart]

do you know where i can get one of those green books?

[pstewart]

We have problems from time to time with a type of barber pole that can be mask or camouflaged in the finishing process in thru feeding centerless grinding, but if you take a piece of polish emery and cross-hatch surface it will develope and you can still see bands. We are using a 120 grit 20" x 6" x 12" wheel on 52100 material 63 - 65 RC hardness. Does anyone have any input as to what causes this and how to solve this problem?