Bandsaw Circle Jig v3

[glenn bradley]

I will be using a round table top on a current project and a couple others following and so wanted to further refine my BS circle jig.

I laminated a piece of scrap luan to a piece of scrap ply while pressing them flat. I used a dado stack to cut a slot for the t-miter track.

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The t-miter and t-bar come from Peachtree. I cut a couple pieces of the t-bar and tapped them for 1/4-20. I couterbore holes in the ply for bolts with washers and use 5/16" through holes to allow for some adjustment.

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The t-bar slides into the BS t-miter slot and the bolts get snugged down.

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The rear is held with a roller stand and a couple cleats attached to the bottom of the ply.

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A stop with a couple pivot options is made from another piece of the t-bar. A 10-24 or 1/4-20 screw from underneath project through the t-bar "stop" to provide the pivot. A pair of 1/4-20 x 3/8" long allen set screws secure the pivot stop in place for 6" to 6' diameter circles.

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And she cuts like so.

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[Will Overton]

Nicely done Glenn. That could come in handy.

[Bill LaPointe]

Nice jig. Will make one tomorrow!

[Mike Harrison]

Nice Jig Glenn, The T track is a nice touch.

I made a similar jig a few years ago for a kitchen lazy susan I did, with 46" shelves. Unless you do a lot of tables these don't get used much.

http://i670.photobucket.com/albums/vv62/mikeinkcmo/WW%20tools/Shop%20tools%20and%20Jigs/Circle%20Cutting%20Jig/circle22.jpg (http://s670.photobucket.com/albums/vv62/mikeinkcmo/WW%20tools/Shop%20tools%20and%20Jigs/Circle%20Cutting%20Jig/)

http://i670.photobucket.com/albums/vv62/mikeinkcmo/WW%20tools/Shop%20tools%20and%20Jigs/Circle%20Cutting%20Jig/circle33.jpg (http://s670.photobucket.com/albums/vv62/mikeinkcmo/WW%20tools/Shop%20tools%20and%20Jigs/Circle%20Cutting%20Jig/)

[Stan Mitchell]

Wow, I really like the miter slot attachment idea to make the whole jig secured to the band saw. Nice setup Glenn.

[Jay Allen]

I would drop the upper guide a least a couple of inches, just for the safety factor, if nothing else.

Nice jig though.

[glenn bradley]

I would drop the upper guide a least a couple of inches, just for the safety factor, if nothing else.

Nice jig though.

Guards backed off for clarity during the photo session :D:D:D

Mike, sweet jig. I really like the folding adjustable leg.

[Robert Horky]

Glenn, really like the cirlce jig ... and appears I have the same (very similar) bandsaw. Working in the jig as I type this. I noticed you added some dust collection up into just below the table and tied it into the hose exiting the port in the lower housing of the bandsaw. Purchased components, home made ... can you provide some insight here as this looks like a great idea as well. Thanks.

[Pete Bradley]

And there I've been sticking a clipped nail in a scrap board clamped to the table!

Pete

[Kelly Craig]

After years of hobby and professional woodworking, I finally made my first circle jig for the band saw (I only upgraded to a real band saw a few years ago). Actually, I made two.

The first was nothing more than a piece of 3/4 ply about 10" square and took less than twenty minutes to make. I attached a miter guide of hardwood and drilled and marked several radius point's I'd be using. Because they were small circles, the radius marks would have been close, had I not off set them (facing the band saw, I moved them forward and back from the operator, drilled the holes and wrote down the diameters each hole would make.

I ran my first test piece and immediately fell in love (we'll talk about tool and jig harems on another day). On my third cut, the saw started giving me fits. I checked wheels, replaced the 3/16" 3TPI blade, readjusted rollers, check tire tracking and so forth. It still wanted to push the blade off the tire and otherwise bind it. Sometimes it didn't.

As it turned out, it was all cockpit error. I was missing a piece of information. Most the jigs touched on stops and such, but didn't really make clear their importance, or function.

I scribed lines from each pivot hole to the edge of the plywood where the blade nearly touched the jig. I placed a pivot pin in a given hole and slid the jig down the track until the corresponding line aligned just in front of the blade. I then set a switching magnet as a stop and backed up to set up for the cut.

I ran several test circles and each one was a dream, as long as I repeated the process for each pin position. Moving forward or back even an eight of an inch or less reproduced the problem.

Now I was sold on the jig. I had to build a quality one. Like my test jig, I didn't want to have to cut a notch just in from an edge, for a starting point, or to have to start dead on the edge of the material. Instead, I push down the miter slot and a 3/4"x1-1/4" trim piece on the operator side of the jig stops forward movement at just the right place.

Like this one, circle sizes are variable from a couple inches to about forty inches.

I'm often lazy and will four times as much work to avoid a project (I learned it from my kids, don't know where they learned it from). As such, my next improvement is a much longer pivot bar with several drilled and tapped holes. This will allow me to use a regular knob (male thread). By moving the knob to center, the left or right, I can tackle most circles without having to remember where I put the Allen wrench.

I choose to extend the jig ten or twelve inches past the blade, toward the inside of the throat, so the twenty inches to the right of the blade, much of which was already supported by the table, was counter balanced. This is to reduce the tendency to tip (until I attempt circles that require the pivot be placed beyond the support of the table).

One of the immediately obvious improvements of the fancier jig and extended table came from that having the jig extend beyond the blade, deeper into the throat of the saw, cut sawdust to a fraction of what it was when a small jig was used, with none of it extending beyond the blade.

A SIDE NOTE:

I was ambling about the nearest city some days ago and happened by a metal salvage place. They sold aluminum stock and I found a piece 3/8" x 1-5/8" wide by about five feet long. It cost seven dollars. I brought it home, set my 7-1/4" fine tooth blade for a 3/4" (miter track width) cut, set some feather boards and knocked out two long miter bars for a fraction of the price it would have cost me to buy them.

The end product did require sanding because they do come out with very sharp edges.