Jerry Bennett’s Wedgie Sled is a wonderfully simple and elegant solution to the problem of cranking out trapezoids for segmented turning. If you’re not familiar with his idea, visit his site and watch his video series.
The only hard part is what to do about setting the angle between the two fences; here are a few options:
- Buy angle setup blocks – Jerry has them available but they are expensive!
- Use a digital protractor – I tried iGaging’s protractor but it’s not accurate enough for this application. A resolution of 1/2 degree just isn’t good enough.
- Make your own – but how??
The problem with making your own is that the angle temple needs to be quite accurate! The template’s error will be compounded by each segment in your ring; this is the basis for the “5-cut test” for squaring up a table saw miter fence.
The route I went with was to use machinist’s setup blocks to create my wedgie sled angle templates. I got this cheap set off of Amazon, whose smallest angle is 0.25°, and biggest is 30°. One can set up a wide variety of angles by stacking up two or more blocks.
Making the Template
I made my template out of a 3/4″ thick piece of MDF, although in the photos below I have the cut setup demonstrated with a piece of plywood.
The goal is to make a triangle with one angle being 360/n, where n is the number of segments in your ring. I was doing 16 segment rings so my n was 22.5°. And if you dust off your High School geometry, a little application of like triangles will show you that the angle between the two wedgie fences equals the included angle of each segment – very simple!
In the photos below I have three stacked angle blocks to get my cut: 20°, 2°, and 0.5°. It’s very important work off of a clean edge so that no fuzzies throw off your work. Here was my sequence:
- Cut one edge of the board to clean it up
- Rotate the board 90° clockwise so that the clean edge is against the miter fence – Take another light cut to clean up that edge
- Add the angle blocks, creating as wide of a triangle as you can.
- Take your time with setting up this cut! Be extra sure that your clamping mechanism doesn’t move the work.
Extra credit can be earned by “squaring up” the triangle – making its two short ends parallel so that you can set up your wedgie sled fairly square to the blade. To do this, I used a half-angle setup, 11.25° and a little square. If your wedgie sled is skewed a bit, your pieces will still have perfectly accurate sides but the inside and outside faces will be skewed a bit.
Using the template block is pretty easy, just smush your fences against it and tighten them up! The other photos are my rings, all of which were one-shot affairs: all the segments were cut & glued in one sequence. No half-rings or sanding needed.