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care and feeding of granite surface plates??

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  • care and feeding of granite surface plates??

    i`m just getting into using surface plates- got by with just my mill table until now.

    any tips,tricks, etc, in the usage and care other than just keep it clean?

    probably covered apologies in advance if it`s a stale subject.

    FWIW- i have a 12x18 grade A import plate

  • #2
    I have an 18" X 24" and a 24" X 36". I made covers for my two granite surface plates out of wood with Lexan top panels. When the covers are placed over the surface plates the Lexan tops clear the surface by about 1/8". I used Lexan because it reminds me (and my students) that it is not a hammering surface but objects may be placed on top of the cover gently.

    A surface plate is a precision gaging surface and must be kept spotlessly clean as much as is practicable. I bought a gallon of Starrett surface plate cleaner and still have more than half a gallon after 5 years of use. If you leave clean your surface plate and leave it uncovered for a day or two (or even less) then wipe your hand over it you will feel the dust that has accumulated even if you can not see it. I use a soft 'draftsmans brush' to whisk off any dust before and after each use.

    Wash all the oil off of parts and instrument before using them on the plate.
    Do not use the uncovered plate as a dumping ground or storage area for parts and instruments.
    Just as you wouldn't use a micrometer as a C-clamp or your calipers as a spanner... don't use your surface plate as a workbench. It is for gaging (or spotting if you do scraping.)

    Last edited by Void; 01-11-2013, 11:26 AM.


    • #3
      Hi Everyone,

      In the last shop I worked we used 'Windex' or equivalent glass cleaner with clean paper towels, often using several towels until they came up as clean appearing as they were before wiping.

      It was felt that the paper did a better job than rags of attracting/trapping dust particles & using clean ones each time stopped any tendency to 'just grab the closest rag'.

      We did a lot of UHV chamber work including the repair/maintenance of electron microscopes and this procedure worked well for us.
      Best wishes to ya’ll.



      "To invent you need a good imagination and a pile of junk" - Thomas Edison

      "I've always wanted to get a job as a procrastinator but I keep putting off going out to find one so I guess I'll never realize my life's dream. Frustrating!" - Me

      Location: Bustling N.E. Arizona


      • #4
        make sure you support it correctly.


        • #5
          Originally posted by jhe.1973 View Post
          we used 'Windex' .
          Starret surface plate cleaner would be better. Cleans well and evaporates.
          The shortest distance between two points is a circle of infinite diameter.

          Bluewater Model Engineering Society at

          Southwestern Ontario. Canada


          • #6
            oddly, even after cleaning with whatever, one can often find additional crud with the hand......

            Cringe all you want....... I find that wiping my hand over the part and the flat as a final step does a fine job. I often find crud, even after cleaning with supposedly lint-free stuff.....
            4357 2773 5150 9120 9135 8645 1007 1190 2133 9120 5942

            Keep eye on ball.
            Hashim Khan

            Everything not impossible is compulsory

            "There's no pleasing these serpents"......Lewis Carroll


            • #7
              Originally posted by J Tiers View Post
              I find that wiping my hand over the part and the flat as a final step does a fine job. I often find crud, even after cleaning with supposedly lint-free stuff.....
              It's amazing that the human hand is as sensitive as it is..
              I cut it twice, and it's still too short!


              • #8
                When it comes to cleaning precision stoneware, the best advise I can give you today is what I wrote on the Practical Machinist board a half-dozen years ago:

                The best commercial surface plate cleaner I ever tried was sold by Rahn. It was a soft, cream-colored paste in a screw-top tin can that sold for US$ 5 a pound twenty-five-plus years ago. Funny thing was that it looked, smelled, felt, and tasted just like . . . um, I've forgotten . . . DL, Go-Jo, Lan-Lin or one of the other national brands of waterless hand cleaner that the local fast-food auto supply stores offered for 1/10 the price in their weekly ads.

                Because of the striking similarity between the Rahn cleaner and waterless hand cleaner, I tried the waterless hand cleaner as a surface table cleaner.

                BINGO! For the past twenty-five years I've been using one or another brand of non-ammoniated waterless hand cleaner without pumice to clean precision stoneware. (The can I'm using now is Go-Jo Original from Ace Hardware's August Sale; US$ 1 for a big can.)

                Scoop a bit out of the can, spread it over the surface to be cleaned, scrub as necessary with a "ok for Teflon" kitchen scrubbie, and sop up the mess with paper towels or shop rags. Works wonderfully well!

                One word of caution: The name of the product is "waterless hand cleaner", but most of them are fundamentally oil-and-water emulsions. To avoid rusting you'll need to allow several minutes for the residual water to evaporate after cleaning your granite flat.

                And for what it's worth, the old Rahn Granite was bought by Tru-Stone, which was in turn bought by Starrett. Starrett Tru-Stone still sells the Rahn paste cleaner, and the MSDS reveals that it's made for them by one of the major makers of waterless hand cleaner, Stockhausen if I remember right. [Note that the current MSDS, dated April 12, 2010, no longer includes a manufacturer's name.]

                Here's a link to the Starrett Tru-Stone website page showing the Rahn cleaner:

                And the MSDS:



                • #9
                  Hey, granite is like, well, err, granite. It is hard to harm except with sharp blows, sharp edges, or abrasive. You can probably clean it with almost any mild soap or NON ABRASIVE cleaner. Do avoid harsh stuff, like bleach or ammonia. I am sure the cleaners made for surface plates are excellent.

                  If you use the hand cleaners as suggested above, do avoid the ones with abrasive in them.

                  Do keep it covered when not in use.

                  I like a soft rag made from old undershirts for wiping it clean for use. I seem to be hard on clothes and have a lot of them. Between old undershirts and other old clothing, I never have to buy shop rags.
                  Paul A.
                  SE Texas

                  And if you look REAL close at an analog signal,
                  You will find that it has discrete steps.


                  • #10
                    Gotta watch what's in any solution used to clean granite. Granite is a natural product of considerable variability Its constituant minerals may be subject to attack from chemicals in common water based cleners.

                    I've used waterless hand cleaners and specific purpose surface plate cleaners sold by Starrett etc but I wasn't too happy with the effort required (try a gelled or "putty" plate cleaner on a 4 x 8 granite flat) or the dead time needed for residues to evaporate. In the end I fall back on lighter fluid to remove tramp oil and skin grease left by my hands and elbows, then a mist with ammonia-less Windex followed by a wipe from clean twhite towels repeating to where the plate is smudge-free and the towels no longer smut.

                    Different strokes of course. The above is my preference and works well even on very large surface plates. YMMV
                    Last edited by Forrest Addy; 01-12-2013, 02:20 AM.


                    • #11
                      I always found brake cleaner works really well.

                      I keep it in a spray bottle in my shop and it lifts bluing right off.

                      I spray the plate then wipe down with a paper towel, it evaporates almost immediately, repeat until no bluing or suchlike shows, then wipe with your hand.


                      • #12
                        The tech people at Starrett told me that regular rubbing alcohol is just fine and very close to the surface plate cleaner they sell.



                        • #13

                          From the Starrett web site:

                          Surface plates are very durable - just use a bit of care - no need to "baby" or "molly-coddle" them. If you scratch them or put a "ding" in them they will still work OK.

                          Last edited by oldtiffie; 01-12-2013, 06:20 PM.


                          • #14







                            I caught someone hammering on a surface plate once. Just gentile taps with a plastic hammer to seat an assembly. That's when they discovered that I do know how to swear... and at a level that would cause a sailor to object. Trick to scaring the ever-loving daylights out of people is only detonate when absolutely necessary.

                            Promise you this though: Neither that person or anyone within a 5 mile radius will hammer on a surface-plate again.
                            "The Administration does not support blowing up planets." --- Finally some SENSIBLE policy from the Gov!


                            • #15
                              Realistically, in many if not most cases if the surface of a surface plate looked like that of some mill table tops it should be made OK the same way - just "stone" the high spots off with a good caurse/fine carpenters oil stone - they are very flat when new - (just as you might do when scraping (a surface plate??)).

                              If in doubt, run a good level over the plate as the base of a good level is very flat and will soon "catch" any defects for further remedial action.

                              If there are any "burrs" etc. running the palm of your hand over the plate surface will soon find any/or most "stick-ups"/defects.

                              Providing that what you are using on a surface plate spans any defects, "dings", bruises or even holes ther will be no adverse effect.

                              Surface plates don't need cotton gloves and cotton wool nor do they need to be stored in a tabernacle with insence burning near-by.

                              A Grade "D" (the least accurate) has been used as the reference in work-shops, tool-rooms and some "inspection" (metrology?) rooms for many years.