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Cylindrical square v Granite Angle Plate

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  • Cylindrical square v Granite Angle Plate

    I was about to buy a cylindrical square from Shars to use as a standard, however wonder if a granite angle plate may be a more useful option?

    I will need to airfreight them out to Australia, so the cylindrical square would be more robust in this regard, but the granite angle plate is both more accurate and I can't imagine anything I couldn't do with it that I could do with the square.

    Does anyone have any first hand experience with these two standards and suggest which would be the better to purchase?

    Here are the two I'm considering:

    http://www.shars.com/products/view/2...te_Angle_Plate

    http://www.shars.com/products/view/2...ylinder_Square

    The second question is, does anyone know the weight of the 4 x 4 x 4 angle plate? USPS have international pre-paid boxes that are an efficient way to freight goods, however their maximum weight is 20 lbs.


    Pete

  • #2
    Pete

    When hand scraping machine tools to recondition them a granite angle plate can be used with a surface plate to apply spotting blue to a piece that has to be at right angle to another face.
    You can check for square with a cylindrical square but not spot for scraping.

    I would like to have a granite angle someday. Could use one right now because I am scraping in my milling machine.

    Dave

    Comment


    • #3
      Thanks Dave, yes I can see plenty of advantages with the angle plate, particularly the point you mention, however the only advantage I can see with the cylindrical square is that it can easily be checked by rotating it on the plate. However I could easily be missing something, and I will need to buy either one OR the other as I certainly can't justify both (or either if the truth is known )

      Pete

      Comment


      • #4
        The weight of a 9"x12"x2" surface plate is 30lbs, which works out to 7.2 cubic inches to the pound. So if the granite angle is as much as 2" thick, that's only 48 cubic inches, divided by 7.2 is 6.6lbs.

        Comment


        • #5
          A cylinder square is a good weekend lathe project.

          I'd buy the granite angle plate and machine my own cylinder square
          I just need one more tool,just one!

          Comment


          • #6
            Pete

            here is a better buy on cylinder square.

            http://www.use-enco.com/CGI/INPDFF?P...MITEM=638-7630

            dave

            Comment


            • #7
              Or you can be a masochist, and generate a cast iron square reference......

              it takes a while, but surprisingly less time than one might expect to get a very good square. You'd have it before the airfreight, but you'd neglect something else to make it.

              A hint...... the other two pieces that are made may not need the whole surface.... you are mainly interested in the ends. If the ends match up and blue all around, you can alternate scraping against a granite flat to get the planar surface.

              The ends get you the angle, the flat gets you the rest of the surface.

              I am suspicious of shop made cylindrical squares. While consistent diameter can be measured with mics etc, it appears that one is "assuming" the machine gets the angle correct. While it "should be" inherent, it might not be accurately "inherent" on *that* machine.

              Scraped parts get , I believe, to smaller errors than measured parts, which may or may not be accurate cylinders, with bases that may or may not be accurately in one plane, free of cam error etc. Any "correction" of "minor" imperfections cannot be guaranteed to be accurate.
              2730

              Keep eye on ball.
              Hashim Khan

              Everything not impossible is compulsory

              Comment


              • #8
                Pete, as a commercial airline pilot, you have the unique ability to sneak damn near anything on the plane. Why don't you watch for a good used granite reference near one of your hubs?
                "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                Comment


                • #9
                  Ah, from what I can see the Enco one is over twice the price for the same accuracy (and possibly the same factory just with a different badge!).

                  As far as machining on a lathe, machining one to this level of accuracy is no trivial task. I think they're normally finished on cylindrical grinders. Turning up cylindrical squares accurate enough for setting up work is certainly much more doable, but I will also simply submit an order for a precision steel angle plate as I need a better alternative to what I'm currently using in this area too.

                  The two alternatives I'm considering here however are basically just references so I would like them to be as accurate as practical.

                  Pete

                  Comment


                  • #10
                    Originally posted by lazlo
                    Pete, as a commercial airline pilot, you have the unique ability to sneak damn near anything on the plane. Why don't you watch for a good used granite reference near one of your hubs?
                    Ha ha, yes and I have done so. Not just good stuff either, half my workshop looks like a HF store, so I sneak back crap too However sometimes these things are just so specialised (in general population terms) that they're not easy to find. Ironically for example it's far easier (and cheaper) to buy Chinese products like this from retailers in the US than the ones in mainland China or Hong Kong, go figure. I used to be up in the US literally one day a week, but I don't go up your way very often at all these days. A shame, as LA was like my second home. For something under 20 lbs it's much easier to simply pay the USPS postage rates and get it within a week.

                    Pete

                    Comment


                    • #11
                      I am suspicious of shop made cylindrical squares. While consistent diameter can be measured with mics etc, it appears that one is "assuming" the machine gets the angle correct. While it "should be" inherent, it might not be accurately "inherent" on *that* machine.
                      Jerry a good hint on auto generating a right angle, thanks.

                      If my logic is working correctly I think a cylindrical square should be easy to check. Mic it as you say to ensure correct diameter, then place it on end and indicate a DTI off the top with a V base hard up against the square. Rotate the square in position and the DTI should indicate the error.

                      Pete

                      Comment


                      • #12
                        I managed to score a Wrist Pin ( Gudgeon Pin ) from a large Cat engine, about 3"x6"...works great for some of the stuff I do

                        Walt
                        Walt

                        Comment


                        • #13
                          Diameter measuring only gets you so far..... you do not know how lobed the part is, since there are ways it can be perfect on diameter and yet not round..... and you don't know that the lobing is parallel to the axis, which means you really don't know if the square is consistently square.

                          Maybe you can blue it in "stripes" axially against a flat and be "pretty sure".

                          Yes, this is VERY fussy..... but we are discussing a reference square, which needs to be made in a fussy way.

                          I think the scraped parts can be made flatter than a DTI can pick up, unless you have one that goes another decimal place.
                          2730

                          Keep eye on ball.
                          Hashim Khan

                          Everything not impossible is compulsory

                          Comment


                          • #14
                            Originally posted by J Tiers
                            Diameter measuring only gets you so far..... you do not know how lobed the part is, since there are ways it can be perfect on diameter and yet not round..... and you don't know that the lobing is parallel to the axis, which means you really don't know if the square is consistently square.
                            It it were lobed wouldn't that show up by rotating it on end as I suggested above?

                            Pete

                            Comment


                            • #15
                              Originally posted by PeteF
                              It it were lobed wouldn't that show up by rotating it on end as I suggested above?

                              Pete
                              I don't think so. You'd have to rotate it in contact with a good v-block to discover "diametric" lobing. Which you could do.

                              Maybe I didn't understand what you meant.

                              I guess the point is that the cylindrical square is so often touted as "self-generating", that it is sometimes missed that it needs to be checked as much as anything else.

                              Scraped squares are checked consistently during, and as part of, the process of making them. And they are to a great extent "self generating".
                              2730

                              Keep eye on ball.
                              Hashim Khan

                              Everything not impossible is compulsory

                              Comment

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