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  • Circle cutter guide for jigsaw?

    I need to cut a dozen 5" diameter holes in some braces, and I don't look forward to doing them with a router.

    I've got a Bosch jigsaw that needs to earn its keep, and while I could cut the holes freehand, I thought that I'd try for something better. Bosch makes a combination edge/circle guide for it, but reviews show it to be weak plastic.

    Festool makes a similar guide for their jigsaws (but made of metal instead of plastic), and I wondered if it would fit in the Bosch.

    Here's the Festool guide...



    If anyone here has dimensions of the part the slides into the Festool jigsaw, I'd appreciate it.

    I can always make an extended plate for the bottom of the Bosch if this doesn't pan out, essentially making a simple "Jasper guide" for my jigsaw.
    Bill Schneider
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    One word = one milli-picture

  • #2
    Re: Circle cutter guide for jigsaw?

    Hey Bill, I have seen your work and bet you could make something just as nice ;) Maybe start with a piece of 1/4" masonite or plywood as a false base plate and add drilled & tapped hardwood or aluminum blocks on either side of your jigsaw's base that could clamp down a steel or aluminum rod via thumbscrews. Oak tapped to 14-20 can do a pretty good job in a pinch! Drill a hole in the pivot end of the rod and you'd pretty much have it!
    Co-conspirator in the development of the "CR Gnarly Fidelity Reduction Unit" - Registered Trademark, Patent Pending.

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    • #3
      Re: Circle cutter guide for jigsaw?

      There's going to be some DIY in whatever I decide to do. The Bosch jigsaw base already has a pair of slots for a flat metal "rod" (like the Festool jigsaw shown), so I'd probably use that instead of making blocks for a round rod IF IT FITS.

      The Festool attachment is only $25, so if the flat metal "rod" fits the Bosch base too, I'd be mostly there. If not, well... Plan B.

      Your post did remind me that I have a Bosch router guide that does circles, and perhaps I can use that instead. It has round rods, so I'd have to make a jigsaw baseplate to accept them like you suggested. The nice feature on the Bosch router guide is that fine adjustments are screw-thread adjustable like a micrometer.
      Bill Schneider
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      One word = one milli-picture

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      • #4
        Re: Circle cutter guide for jigsaw?

        I had a quick look at my Bosch jig and it looks like a 1/8" x 3/8" (or so) bar would fit in there. Obviously measure it and get a bar that fits at the local metal supermarket. For the pivot end just drill a 1/8" hole at the end, I cut old 1/8" drill bits up and use the shaft as a guide pin. The big issue though seems to be how to hold the flat bar securely in the jig saw base. If I get some time tonight I'll look a little more closely at it and pass along any ideas... if I have any.

        Questions:
        #1.) Why don't you want to do this with a router?
        #2.) Would something like this work for you? I have one and they do OK but not a precision tool for sure. Drill press only!

        I just saw they make a beefier version that I think I'll have to pick up for myself.

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        • #5
          Re: Circle cutter guide for jigsaw?

          Yeah, I know there isn't a locking screw on the jigsaw base itself, so I'd have to drill and tap something there. Could be tricky because the only "meat" is on the bottom of the jigsaw base. But I can't have anything sticking down for obvious reasons.

          I don't want to use a router because of depth-of-cut limitations using a spiral upcut bit. I dislike incrementing a cut 1/8" deeper each pass - it slows things down.

          I've also been "banned" from running my router indoors because of the dust. The jigsaw would be much better in that regard because less material is removed.

          I have used circle cutters like your link shows in my drill press, but I didn't like them much. They require a lot of torque, and could possibly damage my nifty aftermarket Jacobs chuck.
          Last edited by williamrschneider; 09-28-2009, 07:09 PM.
          Bill Schneider
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          One word = one milli-picture

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          • #6
            Re: Circle cutter guide for jigsaw?

            I inherited an old Craftsman Jigsaw from 1960 with 3 speed selection and it has a 1/4 thick by 3/8 wide channel and what I did was got a piece of steel from my Brother in-law and put the steel in the jigsaw left about 1/2 overhang on one side then scribed two marks right against the base where the steel slide through and then pre-drilled a couple of holes and tapped them so that I could use the screws as stops on either side and with the remaining 14 -16 I drilled a few wholes where I needed them to be and tapped them with a 1/4" screw that was 2 long and then ground the tip so that way I could screw into the piece and not have to worry about it moving. I needed to make 14, 16 and 18 wooden wagon wheels for a project.
            Worked out very nice...

            WayneN

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            • #7
              Re: Circle cutter guide for jigsaw?

              Oh just man up and cut them with the router ... it didn't take me long to cut 48 holes.

              http://www.htguide.com/forum/showthread.php4?t=34726


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              • #8
                Re: Circle cutter guide for jigsaw?

                if you figure the distance from cutter to outside you can make a guide and use a patern (top bearing) bit and just follow once and repeat.
                " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

                Quote Originally Posted by hongrn. Oct 2014
                Do you realize that being an American is like winning the biggest jackpot ever??

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                • #9
                  Re: Circle cutter guide for jigsaw?

                  Originally posted by WayneN View Post

                  ... put the steel in the jigsaw left about 1/2” overhang on one side then scribed two marks right against the base where the steel slide through and then pre-drilled a couple of holes and tapped them so that I could use the screws as stops on either side ...
                  Originally posted by arlis_1957@yahoo.com View Post

                  if you figure the distance from cutter to outside you can make a guide and use a patern (top bearing) bit and just follow once and repeat.
                  Thanks for the good ideas! The pattern bit I have could cut deeper per pass than the slender 1/4" spiral bit, shortening my time outdoors.

                  The slot for the steel bar on the Bosch appears to be metric. My calipers measured 10mm x 2mm. I don't have a steel supplier in this town, but perhaps there's something in the hardware store. I know they don't have much selection in steel though.

                  Hey Rhubarb9999... thanks for the encouragement to just charge ahead in a manly way. I've done manly things in the past, but this time I want to appeal to my sensitive side. :D :D
                  Last edited by williamrschneider; 09-29-2009, 09:27 AM.
                  Bill Schneider
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                  One word = one milli-picture

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                  • #10
                    Re: Circle cutter guide for jigsaw?

                    A dozen 5" holes...must be the braces for the Reference Recession Buster kit.

                    The way I did it was make one 5" template. Use it and a pencil to draw the 12 circles. Cut out the circles with jigsaw, just inside the line.

                    Then I tacked the template over the holes, one at a time, with small brads.
                    Went to the router table, using a flush cutting bit, ran it around the hole to make it conform to the template. This created maybe 3/4 less dust than using a jasper jig for each hole.

                    If your router table has dust collection, there won't be much for the wife to complain about.

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                    • #11
                      Re: Circle cutter guide for jigsaw?

                      You must be a perfectionist if you circle-jig cut the holes in the braces! :p

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                      • #12
                        Re: Circle cutter guide for jigsaw?

                        Originally posted by pecker View Post
                        A dozen 5" holes...must be the braces for the Reference Recession Buster kit.
                        Ding, Ding, Ding... we have a winner! That's exactly what it is.

                        However my router table is, umm, modest, and dust collection is non-existent...



                        Perfectionist? Not me, but still trying.
                        Bill Schneider
                        -+-+-+-+-
                        One word = one milli-picture

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                        • #13
                          Re: Circle cutter guide for jigsaw?

                          I've got the Bosch 1591 saw, and I made my own circle jig for it. The blank plates for an expansion slot in the PC are just a tad bit too wide, so I cut one down with a pair of tin snips and a file. I inserted it so the hook end of the plate was on the outside of the circle (left side of the saw when holding it) and drilled a hole in it for the screw to secure it. A couple more holes were drilled in the end that was sticking out to screw it to a 3/8" piece of plywood that became the radius for the circle.

                          The circle I was cutting was 36", though, so rigidity wasn't critical. I'm not so sure how this method would work with a 5" circle, it might be too loose.

                          Come to think of it, you can get a 5" hole saw...is there a reason not to go that way?

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                          • #14
                            Re: Circle cutter guide for jigsaw?

                            Take the first pass or two with the router. Finish with the jigsaw freehand with the blade against the outside of the router-cut groove. The groove really helps you stay on course. Saves a lot of time...recently did 90 holes this way.

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                            • #15
                              Re: Circle cutter guide for jigsaw?

                              No reason to bother cutting them precisely if they're just holes in a brace. Do them rough with a jigsaw, and use a small roundover bit with the router on the cut edges to clean it up. Some randomization is desirable here.

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