Cutting an arc

[Robert Hayward]

How do I cut the arc in the picture? I am making a wedgie sled using Corian. I have a good plunge router with bits, collets and so on but am a turner, not a flat worker. What is going to allow me to cut the arcs including accurate stop points ?

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[Wayne Lomman]

Get a scrap of 3 mm mdf or ply. Cut out a temporary baseplate for your router that is tear-drop shaped and long enough to put a pin through at your desired radius. The router attaches to the big end and the pivot pin - screw, nail dowel or whatever - goes into the small end. Use this set up to either make a jig to use with the collar or use it directly. I would make a jig and clamp it on the job.

Turners, flat workers - this is an entirely arbitrary distinction. All wood work is 3 dimensional. The sooner we all understand this the better. Cheers

[Bill Space]

Turners, flat workers - this is an entirely arbitrary distinction. All wood work is 3 dimensional. The sooner we all understand this the better. Cheers

While in theory this is absolutely true, in practical practice I'm not sure it is… 😀

[Charles Lent]

I use my router and CRB7 jig and my router for that. The CRB7 is a multi purpose router jig that offers a lot of flexibility for fine dimensional adjustments when cutting circles and arcs. For stops, I usually use clamps positioned to stop the router travel in each direction, begin routing in the middle and move until it hits each clamp. Watch the YouTube videos on the CRB7 and it's capabilities to see if it's right for you.

Charley

[Steve Shepherd]

To accurately hit the end points, I'd be inclined to drill each end of the arc, then use a router Jig between the two points.

[Robert Hayward]

I am following along. Some good ideas so far. That CRB7 looks interesting.

[jack duren]

You have to make a jig designed to do what you want. The radius and start/stopping points can be figured in the overall jig...Sometimes you have to get creative...


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[Jacques Gagnon]

... wow! very nice work. thanks for sharing!

[Mike Cutler]

Make a jig out of any scrap material just as Wayne suggested.
If you want a longer term solution, that CRB7, or a MicroFence would work.

https://microfence.com

Here's an example of a router cutting jig from Rockler. There are many variations of it available.

http://www.rockler.com/rockler-circle-cutting-jig?utm_source=google&utm_medium=cpc&utm_term=&utm_content=pla&utm_campaign=PL&sid=V9146&gclid=EAIaIQobChMIrdOe2-351QIV1xKBCh2ZgwtGEAQYASABEgJEJPD_BwE

[Robert Hayward]

Here is what I ended up with. I used a simple pattern or jig made from a 3/4" plywood scrap. The stop points for the arc were drawn on the Corian. Then I just stopped cutting when I hit my pencil mark. Thanks to all for the help.

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