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Methods for squaring stock?

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  • Methods for squaring stock?

    I am working on a chess set that is going to require me to make a lot of blocks out of brass and aluminum. Pieces will be made from 1" bar stock, squared up and either 1", 2", or 3" tall depending on the piece. The sizes are all nominal, but I'd like the pieces to match each other by a few thous, or better. Partly for aesthetics, partly as a challenge for me to improve my technique.

    For equipment, I have an X2 that has been converted to CNC, and a 7x lathe. My first thought was to take sections of bar 6-7" long and machine them square on the, and then cut smaller chunks off them which only need squaring on the ends. The length limit is so that I can machine the full length in one pass with a fly cutter or shell mill without making any turns near the ends, so I get a consistent finish.

    Any tips, techniques, fixturing approaches greatly appreciated. I imagine if I wanted to make more than a couple of these I'd look for a larger mill, at least for preparing the stock on.

  • #2
    Start with square stock.

    Comment


    • #3
      Sounds like a good plan to me. Tattoomike seems to have the right answer.
      It's only ink and paper

      Comment


      • #4
        sansbury,

        Take a look at the videos on this link. Great stuff here. I think it is "Machine Shop #6" that details stock squaring on a mill. If not #6 it is in one of the videos listed.

        http://techtv.mit.edu/collections/ehs-videos/videos

        I use the process described in "Machine Shop Trade Secrets" by James Harvey, get a copy you won't be disappointed.
        regards

        3t

        Comment


        • #5
          Originally posted by tattoomike68
          Start with square stock.
          While the simplicity of that gave me a chuckle in the real world that often is not possible.

          My approach if I wanted them all equal as possible would be to machine each separate side as a lot before machining the next side. Same for the ends after you cut then to length, machine the separate ends as a lot before doing the other end. Also use a positive stop in the vise so each piece has the same starting position.
          EDIT:
          Once you get one end of each cleaned up you could also stack them vertically in the vice and face off groups of them, but always in lots.

          This is a simple but very effective stop similar to what I use only I paid $19 for a pair
          http://www.cdcotools.com/index.php
          Do a search for Work Stop on their site.

          Ken
          Last edited by Ken_Shea; 02-03-2009, 12:28 AM.

          Comment


          • #6
            Ken, the irony of the question is "how to square up stock". Now, if he is a machinist he would know such a simple thing as that. Even with a little imagination he should come up with a way using just a lathe. The problem to me is not many think before asking.

            On the other hand I may be a little short with my answer because of the weather we have had.

            To be fair, he didn't give any info about what size he is starting with to make it square. If I give him a fish he learns nothing, but if he has to fish he learns.
            It's only ink and paper

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            • #7
              No argument there Carl, although, from his question I presumed he was just beginning, and having been in the same boat with many efforts I know that what seems so obvious to the experienced is not to those new at it. When new you want to do everything just perfect and it is a tendency to over think what needs to be done, resulting in even more confusion, with experience, perfect results rarely just happen but good work often does.


              Ken
              Last edited by Ken_Shea; 02-03-2009, 12:47 AM.

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              • #8
                Originally posted by Carld

                To be fair, he didn't give any info about what size he is starting with to make it square. If I give him a fish he learns nothing, but if he has to fish he learns.
                no no.. it's "give a man a fish, he eats for a day; teach a man to fish, and you give up your monopoly on fisheries"

                Comment


                • #9
                  Originally posted by sansbury
                  ...........Pieces will be made from 1" bar stock, squared up and either 1", 2", or 3" tall depending on the piece..........
                  That's a good stock to use for chess pieces. It allows you to bore out the bottom to 1/2" and press in some rare earth magnets. Sure would create some excitement on the board if you only did a few pieces and started with them on opposite ends of the board
                  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
                  Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

                  It is true, there is nothing free about freedom, don't be so quick to give it away.

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                  • #10
                    Using sq stock is good because its considerably cheaper. Think about the volume of brass that you are going to make into swarf ...

                    thats money

                    because you pay for stock by weight (essentially). Brass maybe cheaper but its still a lot money for a six foot length of 1" bar (which is what will take if you add up 32 pieces av 2" allowing for cutting etc..).

                    To square it off will waste 36%. (math for max size sq inside a circle)
                    Last edited by derekm; 02-03-2009, 09:12 AM.

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                    • #11
                      But 36c is a lot less than 36p
                      You might not like what I say,but that doesn't mean I'm wrong.

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                      • #12
                        Originally posted by tattoomike68
                        Start with square stock.
                        Look, when it comes to me, out of "fat, dumb, and happy" you can pick any two

                        OK, maybe the part I wasn't specific enough on was that this is for a fancy-schmancy decorative application, so I want the pieces to have a good degree of finish on them. I don't need a mirror-polish, a machined look is fine so long as it is clean and consistent.

                        The stock I buy locally is 1"x1" square, which are sold as offcuts $2.75/lb for 6061, $4 I think for 360. It is square but just the basic mill finish. I don't care if the pieces come out to .923" square so long as they're the same. I've found I need to take up to .05" off each side to be sure of getting out all the corner rounding, dings, etc.

                        Newbie? Guilty. I've done maybe a hundred or two one-off parts, but this is the first project that calls for a bunch of the same thing and where I'm trying to hit tighter tolerances. Sometimes when you are doing a hundred of something it makes sense to optimize the process in a way you don't do when doing one or a dozen.

                        Ken- thanks for the suggestion on doing each side as a lot. I can see where that could lead to more consistency.

                        3t- I've seen that book a number of times in Google searches and found it interesting reading--I suppose it's time to buy a copy and be done with it.

                        Comment


                        • #13
                          Sounds like the pieces are going to be mainly rectangular in cross-section then. How do you intend to break all 384 edges once you've machined all 6 faces?
                          Last edited by tony ennis; 02-03-2009, 10:29 AM.

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                          • #14
                            Place the piece in the vice and mill the first side... then take and place that side against the fixed jaw. Then mill next face and repeat till all sides are done. Also if your moveable jaw wants to lift when you tighten it place a piece of drill rod between the the work and the jaw. To keep from marring the finish you can place a piece of note paper between all the contact surfaces. And as Ken already stated do each face in lots

                            I hope this helps.
                            Wow... where did the time go. I could of swore I was only out there for an hour.

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                            • #15
                              Ok, start with a 4 jaw chuck and reverse two jaws. Put the square stock on the flat of the two reversed jaws and snug them up. Then move the other two jaws to clamp the side of the stock. Does the stock clear the top of the jaws? If not then you will have to space the stock off the jaws.

                              Mark the stock with a pencil so it has a mark centered from the ends and the sides. Put a dead center in the tailstock. Align the center of the stock on the point of the dead center. Tighten the jaws and return the tailstock to the far end of the lathe. Turn the compound so it is parallel to the axis of the lathe. Put a cutting tool of choice in the tool post and align it on the work so that it will cut at center line.

                              Move the cutter using the carriage hand wheel, crossfeed wheel and compound wheel to contact the face of one end of the stock. Now the cutter is positioned to start. back the cutter away from the stock with the crossfeed handwheel. Start the lathe motor and select 300 rpm for starters.

                              Now advance the compound feed in .025" and start the chuck turning. Now manually crank the crossfeed in and make the first cut and stop when the cutter is just past the center of the work. Back the compound off so the tool clears the work. Back the crossfeed crank to the starting point and stop the chuck and look at the work. Is the surface free of blemishes? If not make another cut untill it is the way you want it.

                              Remove the work and turn it 90 deg to begin cutting a new side. Repeat the above steps untill the four sides are clean to your satisfaction.

                              After you have done the sides of all the pieces you can do the ends. For that you will have to reverse the two jaws you switched at the start. Now align the stock in the four jaws so it is centered somewhat, it don't have to be perfect. Now move the cutter to contact the end and retract the crossfeed, move the compound in maybe .40" to clean the end and if not clean take another cut. Do the ends of all the pieces this way.

                              Now your ready to make the Chess men.

                              EDIT: I left out some detail assuming that you could figure it out. Since you did not say if your using a lathe or mill to square the parts I assumed your using a lathe. If your using a mill I can detail the process out for the mill as well. If you have trouble figuring out any of the details I can go into extreme detail of each move to make and how many ways you may be able to do it.

                              As far as doing the CNC part of the work I don't know anything at all about that and your on your own as to programing and tooling for the CNC.
                              Last edited by Carld; 02-03-2009, 10:41 AM.
                              It's only ink and paper

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