# Question about Granite Plate...



## Ray C (Jan 5, 2013)

I have a grade A granite plate, use it on & off and treat it well...  Should it be cleaned with any particular fluid?

BTW:  Every time I pull it out, I check all the squares etc. because the edges are true too.  Just a tip to help pay for forthcoming answers.

Ray


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## Richard King (Jan 5, 2013)

I used to sell Tru-Stone plates who now is part of Starrett.  They sold a water based cleaner and it smelled like Windex, but was red.   I ran out and started to use Windex and it works good.   When I am working in a customers shop and there plate is stained I use acid-tone and it really works good too, but you get high using it.  I also use a one sided razor blade to skim over the plate to make sure it doesn't have any crud dried on it.    Some guys swear by using white paper towels too....Years ago Do-All use to have a plate cleaner that looked like G-Jo.  I think they mix a industrial cleaner and put it in their container for $1.00 and sell it for $16.00, what a deal!

PS:  I always wipe the plate with my hand after cleaning it to so I can feel the dirt, using  rag only leaves lint and crud on the plate.


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## Jeff in Pa (Jan 5, 2013)

I agree with Richard.  We use windex for minor cleaning or acetone if it got more junk.   I too use my hand to make sure it's clean.


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## n3480h (Jan 5, 2013)

Same here.  The one I use at work is 4' x 8' and a foot thick (articulated CMM arm).  I clean it with windex, dry it with white paper towels, and hand wipe to find any particles.  Wish I had that setup at home, but then I'd have to get larger machines . . . . .

Tom


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## anokdoke (Jan 6, 2013)

A couple of things come to mind when cleaning and when not using your surface plate:

using some of those heavy duty shop paper towels (the soft Blue ones) get yourself some waterless hand cleaner (JoJo will work) and using a goodly amount, thoroughly scrub your plate using a circular motion, for a 24X36" plate, fold the towel into quarters and then change quarters for each quarter section scrubbed. You're going to be surprised ad the amount of dirt that comes out!. Once you've scrubbed it, take clean towels and again using a circular motion completely wipe dry the entire plate, changing the towel as needed. Once it's dry you'll find that the plate is completely clean and ready to use. Using your hand to wipe the plate to see if the plate is clean is an indicator that the environment that your plate is in is unacceptable and your measurements could be suspect. (what if you missed some?) Remember that your measurements will be taken somewhere above the surface plate and that Abby error now becomes problematic: If you push your part or height gage up onto some dirt that you missed, you have introduced a "wedge" error (Abby offset) that will cause significant measurement error. Suggestion: Make a box cover using some masonite and edge strips made of 3/4 X1" strips and protect the granite from abrasion by applying several 3/4" felt strips on the underside (where the Masonite sits against the granite) Now you've created an environment that will keep your surface plate reasonably clean until ready to use again. 

Any, by the way, wash your hands before using your plate also.

Mike


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