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  • X-Y layout table

    I've often thought that a layout table would be a good idea. Many times in the past, and again just today I need to layout several holes in some plate material. If I could clamp the plate onto the table, aligning it at the same time, then run a 'work head' across it in both directions to a measured amount, each axis having a dial which shows movement down to a thou or so, I could use that to mark out hole positions, etc. The work head would be able to carry a marking punch, and possibly something like a dremel to use for making pilot holes. Much of what I do with plate is taken to a drill press after the layout and punch holes are marked- otherwise I could probably just do it all on the milling machine. Of course many of the pieces I'd be working with would be larger than the capacity of the mill table axis.

    Anybody have or use something like this?

    I'm thinking that a base surface for it would be a piece of perforated steel sheet, which would give probably hundreds of holes to use for clamps. The X and Y axis would be either leadscrew-driven or cable controlled, with each axis having a dial indicator to show the exact distances that they move.

    I suppose this would be much like a router table, but I don't want to have to interpret markings along a strip of measuring tape for distance measurement. I'd rather turn a dial and then be able to tighten the mechanism at any spot, with an indicated resolution of about a thou or so.

    Whether I use this to draw pencil marks, drill pilot holes, or punch hole centers is up to me. The design of the work head would enable any of these operations to be performed, and of course it could be a router table as well. Down the road I could CNC it.
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

  • #2
    What you are describing also sounds a lot like a good old fashioned drafting table with a drafting machine.

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    • #3
      Yes, I was thinking that also- drafting board mechanism.

      I looked around today and saw what might make a good panel for it- slotboard. This is the stuff that you see on walls in stores, with brackets sticking out . What makes this interesting is that you could place a piece of flat bar into the slots, and that would have some threaded holes in it. It would become one part of a clamp arrangement, which would slide in or out to suit the width of the workpiece. If the table was rectangular, you would orient the slots to span the narrower dimension, thus giving the most clamping points to the longer dimension of the workpiece. I think it could work fairly well. You would need to make a support structure underneath the slotboard to hold it flat, but then it could also be a replaceable piece. After you've drilled into it enough times, you would just replace it.

      To make efficient use of a 4x8 piece of slotboard, I would probably make this table 4 ft wide and 32 inches tall. That puts the slots going in the right direction, and it gives 3 full pieces from the 4x8. It could be smaller of course.

      I can think of some other uses for this type of thing- maybe it will be something worth building for the shop.

      I could certainly make the table up from two widths of flat bar and a backing sheet of steel, and I'd get the same type of clamping arrangement. It would be a lot more work and cost a lot more, and so it would have to become more usable- as in it would become an actual x-y routing table. That would really be the one to make CNC-
      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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      • #4
        A great outfit Portage made a lot of variations on the layout machine theme. Like a CMM with a scribe. The model I used off and on for years was a Portage #72A with a 24" rotary table and a DRO. Incredibly handy for small and mid sized part layout.

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        • #5
          The more I think of this, the more I think I should have one, in some form or another. I think I'll keep the first model down in size a bit, and fairly simple. It will be more useful if I can find a place to put it, or mount it if that can be the case.
          I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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          • #6
            The discussion so far has me in mind of a device based on the vertical
            panel saws most readily seen at the big box hardware stores.
            Rockler Panel Saw

            However, when others speak of plate, I think of material 3/16" and thicker.
            With any amount of material suface area involved, a table substantial enough
            to support such pieces will occupy some real estate in the shop in a
            permanent manner. It is unlike to be able to collapse like a B&D Workmate
            for storage.

            Is a plasma table on your wish list?

            If your purposes justify a permanent table dedicated to plate layout work and
            you have need of plasma table, perhaps consider consider combining the two
            functions. If the X-Y gantry on the plasma table can be adapted to facilitate
            manual layout, this could give you the accuracy/repeatability without tying up
            shop space with a single-purpose tool.

            Perhaps it is even be possible to read coordinates on the plama's display.
            This would be another means of simplifying the layout task.

            .

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            • #7
              Well, there's some good ideas also. I like the idea of a plasma table, but for me that would be a ways off yet. Talked to my boss this AM, and it turns out he had some slotboard on hand, so- as of now I have a table part made, reinforced, and lacquered on both sides for some stability against moisture. It's just over 3 ft wide and 32 inches tall. I've decided to use some 1-1/4 sq tubing for the guideways, and I'll use a cable system to control the motions, just like I did on our table saw fence. That is working wonderfully, by the way, very smoothly and precisely. It's so nice to be able to move one end of a guide and have the other end move exactly the same amount. I want the same thing on this layout table- the only difference here is that I have two axis to control, so two independent cable systems. This will be my fourth iteration of a cable control system, so everything I've learned about it so far will be incorporated into this one.

              Since this model will be operated by hand, I'm not going to worry about future adaptation of motor drives. That will be for another model. The only thing I haven't decided on yet will be the motion detection dials. I have considered a couple of methods so far- one is to lay a section of 1/4 inch all-thread along one of the guides, then run a pinion against the threads. With the right number of teeth on the pinion, I'd be able to divide a dial scale into some exact fraction of an inch (sorry metric people). Two sources of error can creep in here though- one is will the pinion rotate smoothly as you run it along the all-thread, and the other is whether or not the allthread has well-spaced threads along it, and is it accurate over length- unknowns, but I don't trust all-thread to be accurate in either way.

              This method is no different than the way a dial indicator works. The other method would be to use a fine cable under tension, and put one wrap around the dial shaft. As you move the mechanism one way or the other, the single wrap will cause the dial shaft to rotate. The diameter of the dial shaft determines how much rotation it goes through as you move the guide. This will give a smooth dial rotation, but is probably prone to slippage. A shaft diameter of 1/pi will give one full rotation per inch of movement.

              Other methods include adapting glass scales and digital readouts, etc- beyond what I'm willing to do for this first layout table.
              I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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              • #8
                Find an old Behrens (IIRC) turret sheet metal punch... the model I am thinking about had scales and magnifier, for laying out holes in sheet metal. X-Y of course.

                As a side benefit, you can lay out a sheet metal punching template, and then make production parts....

                A decent X-Y table, and a fame with a punch would do it for you. I just use the drill press, or the mill. DP has an X-Y, the mill IS an X-Y.
                1601

                Keep eye on ball.
                Hashim Khan

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                • #9
                  I'm well into the project now, so it will have to go ahead as planned. It appears that whatever mounted tool I have in it will have a range of motion of 24 by 34 inches, and I'll have 1-1/4 inches of room under the sliding carriage, so it will accommodate a 1 inch thick workpiece easily. It will not be a stretch to provide for this much range of height with the tool holder, so it should all work out well. I need to make sure I can see all around the tool, so there will be a large central cutout in the carriage. No snags that I haven't forseen yet- although I didn't think about how heavy this thing might become. With just the basic table and guideways it's already a substantial weight.

                  I'm leaving myself the option of adding some stiffening ribs to the sides of the overarm. It appears that it will be stiff enough as is, but why not stiffen it up more if I can without putting stuff in the way-

                  I'll post a few pics when I have the basics assembled. Whatever else I say about this project will make more sense once you can see what it is.

                  Must eat now- can't live on enthusiasm
                  I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                  • #10
                    I am interested in examples of what you plan to use this device for that can't be done with straight edge, square and scribe. Old school drafting style.

                    You lost me when you state "within a thou or so", then you are going to mark with a pencil and take to drill press.

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                    • #11
                      No, I am not going to mark with pencil/take to drill press. I'm going to have a small dovetailed downfeed mechanism with a spindle on it. I can either use a drill bit in it, or a sharpened punch. I will move each of the axis to the desired location, then lower the tool. For the punch I would use some impact to force the mark, and for the drill I would use something like a center drill to make the dimple. Then I take to drill press.

                      I had that same thought too, last night- if I'm going to just mark lines out, I'm still stuck with the vagaries of that, not to mention how close I'll get the actual punch mark to the intersection of lines. Instead of this, I'll be moving the axis to points indicated by the dials.

                      Then, If I have a y axis setting set, I can move X and know that Y is still in the same place. I can also set X, then move Y and know that X is still in the same place. The punch marks or dimples will always be in the same place relative to the carriage, and if I get the two axis perfectly 90 degrees apart, then the accuracy of my layout will always follow. No more careful placement of squares against straight edges, no more not knowing if the square is even square (many aren't), and no more guessing about where the center of the mark is, or whether the placement of the punch is absolutely correct. I will still have to ensure that when I begin to drill in the drill press, the hole location doesn't wander.

                      I'm sure I'll also be using a dial indicator to align the reference edge of the workpiece before securing it to the table.

                      A design factor that isn't fixed in stone yet is the method of moving the carriage. A leadscrew with no play and a very concentric dial would probably be the most accurate way to go to the wanted positions. This would be slow though, unless I came up with a split nut kind of thing or used a very coarse leadscrew. That I do have- it's a three start acme thread going one inch per turn. Too coarse I think- that would translate into 1000 markings around the dial if I wanted to resolve down to a thou, or it would require that I gear up to the dial.

                      I had kind of wanted to use 1/2-20 threaded rod as the leadscrews, but even the best of what I have and have measured comes out with an inaccuracy over length. 200 threads should get me 10 inches of motion, but I get something like 10-1/16 of motion instead. The periodic error is acceptably low on these rods though. I have some threaded rod where you can visually see the error- obviously not good at all for an application like this.

                      So that's where I'm at. I'll get back to this project later today and I hope to get the major parts all together. I don't think I'll be using the cable mechanism for the Y axis since the guideways will be able to control any skewing, but for the X axis it will be mandatory.
                      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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