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I made a quick and dirty dish radiusing jig today and thought I would post it if anyone is interested.

To begin with, I already have a brace radiusing jig that I use on my router table, so I used it as the template for the router guide rails on the dish jig.


I took the brace radiusing jig, and used the radius as a pattern and traced it onto a piece of MDF, and then cut it on the bandsaw. I cleaned up most of the bandsaw marks with a rasp, carefully. Then I stuck some 120 grit sandpaper to the brace jig, and used it as a sanding block in order to get the arc correct and smooth it. After getting one rail arc right, I screwed another piece of MDF to it, and used the pattern bit on the router table once again to make a carbon copy of the first.

Then I glued and bradded a piece of 1/4" ply to the outer side of each rail in order to capture the router base, and assembled the rails the proper width apart to capture the router base.

Next, I made a base for the rails with 2 uprights to hold the rail assy and elevated it the thickness of the MDF plus the thickness of a framing square (really technical stuff I know!).

I drilled a 3/16" hole in the center of the base and used the pin that comes with the Stewie mac circle cutter for a pivot.


The brace radiusing jig sits very nicely in the rail with no gaps showing.

When making one like this, you have to be sure you have a router bit long enough to reach the final dimensions of the dish, which I do. I had to make about 5 passes with the router, taking off small amounts at a time. Initially, the bit would contact the dish at about 3/4 of the way to its center, and a little further out each time I lowered the router in its base. Also, this thing will get the dish spinning on its own. If it gets spinning too fast, the bit will take a rougher and rougher cut and will eventually end in a screwed up dish (Damhikt) so I took my time so I wouldn't need to use wood filler! I did not notice any deflection in the rails, and I did not need to bear down on the router, as its own weight was sufficient. The whole thing from turning on the shop lights to screwing the dish to a backer board took me only a few hours to do. Now that I have the jig, I should be able to punch one out in half an hour or so.

This is just a down and dirty jig, no math involved and simple to do so I thought I would share it.

Thanks

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Brad Tucker

What would your final radius be?

Well, if the rails are radiused to 28', and the distance from the top of the rail/router base is 2.5" (thats a guess because I'm not in the shop) I guess it would be 28' 2.5"...........hey now wait a minute......

See, now you went and involved math!!!

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Brad Tucker

Yup, thats how I built my dishes. In fact, I use a similar jig as your first pic to shape my braces.

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A higher purpose for wood.
Rich Smith
Issaquah, WA

I'll do the math. 28' radius=3.36" or 3 11/32"