# New circle jig



## Ghidrah (Oct 21, 2008)

After all these yrs I finally built an adjustable circle jig, I already have 4, 3 home made and 1 bought. The 3 home made are great for arbitrary measurements but limited in the number of times one can make a new hole very close to an existing one, eventually requiring a new one and I hate that. The bought jig is also great but limited to the number of pivot points, (numerous but to 1/16" increments) and the max diameter which is 7 15/16".

The new jig is 23"X4 13/16"X1/4" it has a radius option between 3.5" to 16" for a 7" to 32" circle.

The jig is made of 3 pieces of plexi, one 1/4-20 toilet bowl bolt, one 1/4-20 plastic coated nut, 1/2"X2 1/4"X1/4" piece of pine notched to accept the toilet bowl bolt, one 3/4"-18guage brad and Krazy glue. I already had the plexi, Krazy glue and brad, the pair of toilet bolts and nut cost me $8 at Aubuchon Hdr. I 1st tried a 2 part epoxy which at 1st looked good till I arched the jig slightly while clearing excess poly 6 hrs after glue up, one of the 1"X13 3/4"X1/4" strips sprang off. So far the Krazy glue has made an excellent bond and probably saved me $10 to $18 for real plexi glue. 

The main body of the jig has a 1/2"X13 1/4" slot to accept the wooden piece; I lined up the center line with my TS blade and kept rotating the jig and widening the space between blade and fence till I had the half inch. I milled 2 wood blocks to dim and fit the bolts, set them in the slot then slid the 2 1"X13 3/4"X1/4" strips up to the bolts. I clamped strip #1 with 4 spring clamps, removed 2, pulled strip #1 away from main body and spread the Krazy glue. Reclamped, side #1 of strip #1 then repeated the previous with side #2 of strip #1. An hour later I did the same thing for strip #2 then chiseled off the excess glue a couple hrs later.

I tested the jig about 30 mins ago and it worked smooth, so far so good. Next step is to use the new jig to cut another new jig that'll allow me to work on my next project.
I think if I change anything it would be going with 5/16 or 3/8" think plexi and widening the adjustment slot to 5/8" to accept a more substantial wood block .


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## tvman44 (Jun 25, 2013)

I went the lazy way and bought one from Rockler.


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## Stick486 (Jan 4, 2013)

tvman44 said:


> I went the lazy way and bought one from Rockler.


me too...


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## neville9999 (Jul 22, 2010)

Nice looking circle Jig. N


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## DesertRatTom (Jul 3, 2012)

Nice jig. You have more patience than I!


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## GregLittleWoodworks (Dec 9, 2014)

Stick486 said:


> me too...


Me three...


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## Ghidrah (Oct 21, 2008)

Believe me, I know lazy, you can't see it cause the L is invisible in Ghidrah. 

Frankly the actual work took maybe an hour the toughest part was getting the double sided tape to let go of the PC base and plexi. The epoxy failure was a disappointment but the ultra thin epoxy film came off easy. I'm thinking even though un-necessary sometime in the future I might buy some sticky ruler. Aligning the router bit to a drawn arc is effortless, I don't know why it took so long to do it ... oh yeah, right, I'm lazy.


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## papasombre (Sep 22, 2011)

Nice jig!!!


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## Cherryville Chuck (Sep 28, 2010)

Making one that works is at least twice as satisfying as buying one.


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## Ghidrah (Oct 21, 2008)

I made my 1st cuts today with new the circle jig, it was to create another jig, (a simple arc to fit the modified template guide). While the results were acceptable, the pine block used to lock the pivot pin in place in the adjustment slot flexed too much at the beginning and end of the operation. Ends being at approx. 60° from -0-, the flex translated into a +.011 at the beginning of the cut and a +.013 at the end, the middle area, -0- to 45° from +.003 to +.007. By the feel of it, I would have been happier than a P.I.S., at the 90/-0- it is a tight .003. My intention was to make it a smidge too tight then hand sand to fit and slide.

I junked the pine block and remade one out of maple then added 1/4X1/4" reinforcement blocks to either side of the toilet bolt, it's stiffer than a cadaver 6 hrs cold. I intentionally made the arc jig 2" longer than the required cuts so that the bit would begin and exit outside the object. I made a test cut with the new jig, Whiteside 2058 and modified template guide. Even with the excess space at the ends of the cut is acceptable. Hopefully the promised rise in temps will make my shop habitable for more than 30 to 45 mins before my finger tips go numb.


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## Paul Brierly (Feb 19, 2015)

Thanks as I need to make one to for cutting out some circular hatches in the interior of my boat. Luckily I have the all the parts required required


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