trouble with a lap

[Brent Hickenbotham]

I was cold working tonight on a diamond lap from HIS and on the 220 grit I was getting a pretty good gouge and couldn't find it in the wheel. There was nothing imbedded in the back of the magnet, and there were no stray comet tails signifying a larger grit in the mix and no visible dents or abuse. Don't know if I'm just tired but couldn't find it. anyone got any suggestions? bob u out there?

[Pete VanderLaan]

take a little piece of glass and run across the head slowly from inside to outside with the water really running. Make the piece small so you can feel the obstruction in an isolated space.

If you are really lucky you will see something at that site when the wheel stops. Dealing with it may or may not be possible.
This is what I hate about diamonds. A perfect surface with one long scratch. It happens again and again. Grit doesn't do that.
I have been using diamonds in our basement and really don't like them for quality surfaces. The only advantage I can see is no slurry and that is a big advantage. It could be that you need to break the edge of the piece you are grinding on a belt sander. A squared off rough surface sheds little chunks of glass continually contaminating the slurry. You'll have to contact Bob at HIS own site for other advice.

No free lunch.

[Scott Novota]

I actully asked this question of Bob at GAS. I have 12 inch lap and was having this exact problem.


Alas, I know exactly where mine was and had what looked like a "comet" from the offending diamond that is sticking up on the pad. He told me to take a very light hearted tap to it with a hammer to break the offending diamond. Sure enough that worked and I don't have the offending scratch any longer.


Find it, give it a try. Hope that helps. Light tap...increase in force in lightly until you crush it.


Scott.
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[Brent Hickenbotham]

Thanks, I've had this problem before too and was easily fixed, one tome i popped out the stray diamond with a razor blade like bob said, and the other was with the hammer (bobs advice) like you said scott. But this one is a phantom and its pissing me off. I'll figure it out tonight.

[Scott Novota]

Your a step ahead of me then.


Scott.
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