Circle Jig – Anyone have any experience?
KesslerCraftsman
| Posted in Power Tools and Machinery on
Hi.
I’ve agreed to make a circular molding for a client’s door….they can’t buy this anywhere, the local millworks wants $280 to make this little piece.
Basically my plan is to glue up maple stock (since the circle is 28″ diameter), hot glue it to a piece of baltic birch to keep it in place temporarily and then cut the inner and outer diameters with a straight bit in the router and the circle jig . I’ll then just use an ogee for the inside…where there’s need for a touch of decoration….
Anyone have experience with circle jigs for a router? Any brands or recommendations in using them?
Thanks in advance!
Replies
Circle jigs are just a length of plastic with several holes drilled in it ,to use nails to pivot it .And the router )
(Much like a trammel point set) attaches to your router base in place of the existing base
Depending on the router bit you use ,you'll more than likely have to drill a new pilot hole anyway to rout out to the exact sized inner and outer circles
I make my own for this purpose from 1/8" Masonite, but make sure the type you make/buy is long enough for both the inner and outer circles.
Of course, you'll first have to miter the 'Sectors' and spline or biscuit and glue it all up before the routing begins. Steinmetz.
Edited 8/24/2004 8:27 pm ET by steinmetz
Edited 8/25/2004 3:12 pm ET by steinmetz
This is a really expensive item. Probably $10.
We have a placed called Tap Plastics locally that sells acrylic and polycarbonate plastics. You may have a similar store.
Buy a piece of 3/8" thick by the width of your router base (+ 1/2") and the length of the radius of the circel (+ some inches).
Use the router base as a template to cut the plastic.
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Michael in San Jose
"In all affairs it's a healthy thing now and then to hang a question mark on the things you have long taken for granted." Bertrand Russell
Another approach? I had to do a pair of arched casings for my home. Mill shop was out of sight. Scraf glue some stock (I used pine), bandsaw the shape, and smooth. Then with a router and BB guide, put in your primary recess. File a scraper balde to the molding profile, and scrape away. Takes less time than you might imagine. Just a thought.
Alan
http://www.alanturnerfurnituremaker.com
You're about to find out why the local millwork shops charge 280 bucks.
Not a biggie, but this one cuts circles in 2.00" increments to 12.00". Cutter diameter matters.
I've had great success making a temporary routing jig using a sheet of plywood and a trammel.
I like to do a fullsize layout drawing the piece and block the piece to the plywood to keep it exactly where I want it.
6" by however long 1/2" trammel with holes drilled at apprpriate radius for inside and outside cuts.
Larry, sorry for checking in late, but here goes. Caveat: I'm no pro.
Sounds as though you want a one-off use for two sizes of circle (inner & outer). Two methods come to mind: First is, make a homemade circle jig out of available scrap, thin plywood preferred if available. Your circle is not huge (14" radius) so you can probably do on a benchtop, or attached to a plywood substrate on the floor if you rather. The second option is to cut a pattern out of something like Masonite or ½" MDF, then use a pattern router bit or flush-cut bit to get the shape out of the workpiece.
My paranoid preference would be to nail the workpiece down when routering (nailing through parts to be cut off the ends later) instead of hot-glueing.
One thing you want to look out for if using the circle jig is the difference in height from one end of the trammel bar to the other - make it so that is level, preferably. You can get the length just right through trial and error, adjusting by drilling a new hole in the fixed end of the bar then nailing through. You can clamp or screw the bar to your router.
Honestly, the last time I did this was a couple of years ago; the radius was about 10', this was for a garden arch in cedar. I used a long 1x4 as the trammel bar, clamped it to the router base with spring clamps, and anchored the other end to a board on the floor weighted with a bag of concrete. The workpiece, about 6' long, was also weighted with 55# bags. I cut in segments, shifting the bags as necessary. This got me halfway through the 2" thickness of the arch, then I changed to a pattern bit and used the first cut as a template for completing the thickness.
Best of luck, Chrisx.
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