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Granite Surface Plate Advice

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  • Granite Surface Plate Advice

    I'm looking at purchasing a surface plate from Enco and wanted to get some thoughts on grade A vs grade B. The site says that the tolerance for Grade A is .0001 and Grade B is .0003. I'm a hobbyist so I figure grade B is good enough for most any application I do. Any thoughts?

    Thanks!

  • #2
    plate

    Get the best and biggest plate that you can afford, then there are no second thoughts.

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    • #3
      That certainly would be the motto I have lived by for a long time . The choice is between a 12x18x3 grade A or a 18x24x3 grade B. I'm leaning towards the grade B since the tolerance isn't too much different and I get twice the plate.

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      • #4
        Lets put this more into perspective,

        Grade B = Toolroom grade.
        Grade A = Inspection grade.
        Grade AA = Lab grade.

        There are very few people on this board that would ever need anything better than a Toolroom B grade.
        I have a Toolroom grade Starrett Crystal pink, that I have had for over 25 years now, it was relapped about 3 years ago to an inspection grade plate. The company I work for re lapped all the plates in the plant, mine worked fine for a B grade for them for many years, the company just insisted on spending money, who was I to turn it down.
        Just for more info, Starrett pink granite plates are harder than black granite. They have a higher quartz content so they will also last longer as far as being flat and such.

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        • #5
          Keep in mind the bigger one weighs twice as much as the smaller one. If I recall correctly, my 12x18x3 weighs more than 70 lbs. so the bigger one would weigh over almost 150 lbs.

          When I bought mine, I planned on keeping it under the bench and just pull it out when needed. HAH! I forgot how much 70 lbs. is so I made a stand for it. My back thanks me for it every time I use it. Oh yeah, B grade is fine for my HSM use.
          Milton

          "Accuracy is the sum total of your compensating mistakes."

          "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

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          • #6
            ...and here's a link to my surface plate/buffer stand in case you're interested:
            http://bbs.homeshopmachinist.net/sho...ghlight=buffer
            Milton

            "Accuracy is the sum total of your compensating mistakes."

            "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

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            • #7
              Don't forget your free shipping code: PFSJUN

              What a bargain with the web price and free ship. Weights shown here: http://www.use-enco.com/CGI/INPDFF?P...MITEM=640-0140

              Last edited by knudsen; 06-16-2010, 07:25 PM.

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              • #8
                How big are you wanting?

                I think the Enco Grade A big one (like 36 by 72 or something) goes on sale for far cheaper than the equally sized Grade B one. Something like 500 for Grade B or 340 for Grade A

                'Course then there is the discussion about whether these grades actually mean anything coming from China and with no NIST cert.

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                • #9
                  Grade B will be fine. Any better than that and you'll have to start worrying about temperature differentials.

                  Personally, I've always found 12x18 big enough, and it's movable without a crane.
                  ----------
                  Try to make a living, not a killing. -- Utah Phillips
                  Don't believe everything you know. -- Bumper sticker
                  Everybody is ignorant, only on different subjects. -- Will Rogers
                  There are lots of people who mistake their imagination for their memory. - Josh Billings
                  Law of Logical Argument - Anything is possible if you don't know what you are talking about.
                  Don't own anything you have to feed or paint. - Hood River Blackie

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                  • #10
                    I've already arranged for mine to see double duty.

                    In this life I'll use it to lay out the various projects I have.

                    My heirs have been instructed to use it to lay me out (headstone), when I'm through with it.

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                    • #11
                      I was hoping for free delivery with the coupon but it looks like the coupon isn't good for heavy items that are shipped by truck. Anyone able to confirm this. May try it with the smaller plate and see if that works.

                      Dale

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                      • #12
                        Originally posted by Dale Lusby
                        I was hoping for free delivery with the coupon but it looks like the coupon isn't good for heavy items that are shipped by truck. Anyone able to confirm this. May try it with the smaller plate and see if that works.

                        Dale
                        12" by 18" is the biggest plate that will get free shipping. Sometimes (especially if the order is big of you've placed big orders in the past) you can call them and convince them to give you free truck shipping, as long as you don't need a lift gate. I got free shipping on a vise this way, despite the fact that it weighed ~120 lbs.

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                        • #13
                          How do they ship these things?

                          Inside a wooden crate of some sort?

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                          • #14
                            heavy cardboard box, about 1/2 inch thick

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                            • #15
                              Get the bigger plate. I have had many times where I do precision assemblies on my plates that need to be lined up "just right" where indicators and angle irons are needed as well. A 12 x 18 does not hold a lot of extra "support gauging" like this, and a larger part, or indicators, angle irons and gauge blocks take up more room than you imagine. Just think 6 inch x 6 inch angle iron, 3 x 3 indicator stand, the overhang, parts, and maybe a 5 inch sine bar in the mix and a dial height gauge or vernier height gauge - normal day in my shop.......


                              Then someday you may wish to grind up a machine vise.....

                              I have two 24 x 36 inch, a 24 x 24 that is a cramped "heightmaster (the probe gauge type) station, and a couple of 12 x 18's, the 12 x 18's are "quick inspect" stations or flatness checkers.

                              Bigger, grade B will suffice for a HSM for the most part.
                              Last edited by spope14; 06-16-2010, 09:43 PM.
                              CCBW, MAH

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