Woodworking Jigs

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  • Woodworking Jigs

    Hello, I looked through this website and I am not sure if I am overlooking it or not. At one time I could've sworn there was a discussion board over different jigs people have created for the BT3000. I am particularly looking on a jig on how to cut circles. I wish the BT3000 had a miter slot or wish I had the miter inserts, if you know where I can buy some let me know!! Another question I haveis, has anyone made a new table top for their saw? Made it bigger and with their own miter slots?Thanks in advance!

  • #2
    Cutting circles on a table saw is rather dangerous and I don’t recall seeing a jig for that purpose for any table saw. If you go to the articles section here, you will find many jigs and fixtures for the BT3Ks that duplicate jigs quite well that a saw with a miter slot would use. I’ve been using my BT3K since 1993 and have never needed a miter slot and I never considered buying or making one. Early on in the BT3K life cycle, there was quite a fuss made by traditional table saw users about the lack of a miter slot and how you couldn’t use traditionally marketed miter slot accessories. Ryobi brought the miter slot accessory out to counter the fuss. The accessory limits the adjustability of the system. The accessory tables have a rabbit on one side that forms a slot when positioned next to another table on the BT3K. As for a larger table for the BT3K, I have rarely seen the need for one. I did design and make a folding out feed table to extend the working area and I even set up another table for really long stock. The adjustable rails permit large workpieces to be cut by the saw. A BT3K has a maximum rip width of 33” and I have cut 4’x8’ sheets of plywood with ease. I compared my BT3K with a relative’s 3 hp PM66 saw and found it could cut everything the cabinet saw could. In some instances, the BT3K had greater capability. Some users have mounted the saw in a larger cabinet to provide a larger work surface and that makes the saw footprint larger.
    Last edited by Jim Frye; 11-22-2020, 11:05 PM.
    Jim Frye
    The Nut in the Cellar.
    ”Sawdust Is Man Glitter”

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    • #3
      Making a circle cutting jig on the BT3 be fairly simple with the SMT. Easier than most saws.

      I would take a 15 x 15 inch piece of plywood or MDF. Attach a 1x2 lip to one edge. and place a dowel on the plywood. As shown below
      Click image for larger version  Name:	BT3 table saw circle jig.JPG Views:	0 Size:	64.2 KB ID:	841424 The dowel pivot will need to be like 1/4" and will be a hole in the center of your circle. But it can be a closed bottom hole so it needn't go through. Actually it could be a nail driven in from the bottom if you need a small center hole.
      Clamp the 1x2 edging to the SMT miter fence securing the jig..
      Remove the rip fence completely.
      I would slide the jig right edge up to the blade. Then the pivot to blade distance is the radius of your circle.
      You can raise the saw blade... the more height the more vertical the blade will be where it hits the workpiece.
      If you move the SMT all the say back then there can easily be 15" workpiece in front of the blade.
      Now is the repeated action. Slide the SMT forwards and backwards. With the SMT back to you and clear of the blade, rotate the work a few degrees and repeat.
      Gradually with a lot of passes, the workpiece will become a circle.
      When its close, you can slide the SMT to where the pivot is opposite the point where the blade makes contact and at that point, lock the SMT in place (a one handed quick grip clamp on the left holding it to the SMT base will work) and rotate by hand the workpiece around the pivot, this should clean up the circle pretty well... this is where the more vertical blade portion helps.

      Size. This will easily cut as large as 28" diameter circle, I think. You can place pivots closer to the blade, as the radius gets smaller, you can also move the pivot closer to the miter fence.
      The upper limit is the distance between the saw blade front edge and the miter fence. Lowering the blade will increase this distance a bit. Also there is a trick in the BT3 FAQ for modifying your SMT to place the miter pivot holes close to the front edge (giving up miter angles for more width). I think the 21829 Sears saws already have these pivot holes.
      The radius of the pin to saw distance is also adjustable other than by moving the pivot... the SMT can be slid sideways and the rails can be slid to the left and extensions used if you wish.

      Use appropriate safety devices; especially be aware that the workpiece will want to spin when it encounters the blade! repeat, the workpiece will want to spin!
      This requires a firm hold of the workpiece. You are responsible for your safety. I have done this, once, I think.

      BTW this also works on bandsaws which is where I first saw it, using the miter slide and the miter slot. Because the bandsaw can cut a curve, you don't have to move it back and forth like on a table saw,
      Last edited by LCHIEN; 11-24-2020, 01:20 AM.
      Loring in Katy, TX USA
      If your only tool is a hammer, you tend to treat all problems as if they were nails.
      BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

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      • #4
        I'm not sure I would want to use my BT to attempt cutting circles, as my first thoughts would be to look to a bandsaw. But after reading Loring's description, it sound's like the BT's miter slot might well serve that purpose in good style.

        Reading the description got me to wondering and I looked back at one of my favorite old books, "De Cristoforo's Complete Book of Power Tools", Copyright 1972 by R. J. De Cristoforo. The book covers multiple power tools and offers application solutions for most of them. On page 46 and 47 the author shows photos of making such a cut by placing a pin in a hardwood piece that is cut to fit the miter slot. Basically cutting a square of the stock, you then locate it on the dowel by driving a nail through the center of the stock, into the miter bar you've made, and then using the miter slot, you trim the corners off the perimeter to the diameter you wish. After each cut, you rotate the piece and make the next pass through, repeating the process until you have multiple flat cuts around the perimeter, basically a circle with multiple straight cuts. At that point, you should be able to then clamp the bar in position and just rotate the stock to smooth off all the edges.

        With Loring's description, the BT's Sliding Miter Table would certainly seem to facilitate such a cut with style.

        But while It looks easy enough, note that I have great respect for the table saw and so extreme caution is paramount. (Basically, my 'keep your fingers' philosophy is 'if it doesn't feel comfortable, don't do it')

        I'd like to scan those pages, but I'm sensitive to copyright requirements and wouldn't want to violate that. Your local library may well have the book.

        CWS
        Last edited by cwsmith; 11-23-2020, 09:03 PM.
        Think it Through Before You Do!

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        • #5
          Basically if using my jig, you have to hold the workpiece firmly while making the sliding cuts, If you let go, the workpiece will rotate (if ten inches diamter it will match the RPM of the saw blade) and it will take off like a frisbee.

          But you can't let go while feeding a piece into the saw for a ripping operation, or it will fly off.
          The difference is that the workpiece will want to spin if the blade bites into it. But it should take no more hold down force than a normal feed operation. Just don't let go while feeding. I suppose to be really safe you can mount at hold down toggle clamp to the workpiece at the 7:30 position on the jig base or even use the Ryobi miter fence clamp on parts of it.. But you should be able to concentrate long enough to hold the piece down with hand force.

          Just be aware of where the forces are going.
          Loring in Katy, TX USA
          If your only tool is a hammer, you tend to treat all problems as if they were nails.
          BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

          Comment


          • #6
            The times I’ve cut circles on the table saw I don’t remember it cutting flat edges, just a radius edge. Band saw is the way to go and has little clean up.

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            • #7
              Originally posted by capncarl View Post
              The times I’ve cut circles on the table saw I don’t remember it cutting flat edges, just a radius edge. Band saw is the way to go and has little clean up.
              table saws can't make curving cuts like band saws.
              So generally with a bandsaw and a 1/4" blade you can make a circle cut directly to a squared piece.
              With a table saw, you make a square piece to a octagonal stop sign with the first four sliding cuts, then make 8 more cuts to a 16-sided, then maybe 16 more to 32. By then you can probably simply rotate the workpiece without sliding it as the blade will be shaving off more than cutting straight lines..
              Loring in Katy, TX USA
              If your only tool is a hammer, you tend to treat all problems as if they were nails.
              BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

              Comment


              • #8
                Originally posted by LCHIEN View Post
                Basically if using my jig, you have to hold the workpiece firmly while making the sliding cuts, If you let go, the workpiece will rotate (if ten inches diamter it will match the RPM of the saw blade) and it will take off like a frisbee.

                But you can't let go while feeding a piece into the saw for a ripping operation, or it will fly off.
                The difference is that the workpiece will want to spin if the blade bites into it. But it should take no more hold down force than a normal feed operation. Just don't let go while feeding. I suppose to be really safe you can mount at hold down toggle clamp to the workpiece at the 7:30 position on the jig base or even use the Ryobi miter fence clamp on parts of it.. But you should be able to concentrate long enough to hold the piece down with hand force.

                Just be aware of where the forces are going.
                Not sure I understand the 7:30 position

                Great drawing and the explanation nevertheless

                Thanks,

                NG

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                • #9
                  lower left corner, like a clock
                  Click image for larger version

Name:	circle jig 2.png
Views:	48
Size:	274.3 KB
ID:	842062
                  Loring in Katy, TX USA
                  If your only tool is a hammer, you tend to treat all problems as if they were nails.
                  BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

                  Comment


                  • #10
                    Aha !!

                    OK got it now. Makes sense - perfectly half way between 6 and 9 o'clock positions. Dumb me .

                    Thanks ......

                    NG

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