Fin Beveling Jig

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by James Weaver

Brief:
My own try at fin beveling using a jig inspired by the one built by John Coker at Info Central.

Construction:
I wanted to give my latest scratch build a bit of a different look, so I decided to try my hand at adding a bevel to my fin edges. I remembered seeing a jig at John Coker's site that didn't look all that tough to build. I broke out what scrap lumber I had on hand and got to it.

Lumber available: short 1x4 and long 1x6.

Tools available: Dremel combination belt/disc sander, Power drill, jigsaw, clamps, squares, and measuring tools.

My disc sander is only 4" across so my jig could not be all that big. I tried to do everything out of the 1x6 but figured out that I would not be able to clamp the jig to the base of the sander. I had to use my only piece of 1x4 for the base. I used the 1x6 for the face and the supports.

I took some handy-dandy measurements and commenced to cutting. John's rig is set for a 10 degree bevel, but I chose to do a 15 degree bevel, mostly for safety reasons. An added 5 degrees gets your fingers further away from the sanding disc. To get the face the face to lie back properly, I set my power saw base at a 15 degree angle to the blade and made a cut along the edge of the face board. Save the piece you cut off for now. Next, I cut two braces using a square cut but angled 15 degrees to the edge.

With all the pieces cut it was now time to screw it all together. The only screws I had were 1 1/4" drywall screws so that's what I used. It is important to countersink the screws so you fin material does not catch on anything when you make your beveling pass. The hardest part for me was getting the face screwed to the base. I set about a ¼" relief along the base to set and guide the fins. I really could have used some of those long sliding clamps for this because every time I tried to run the screws down everything would slip. Maybe gluing overnight first would have helped as well.

I finally managed to get everything together. It was not perfect but it was workable. The next order of business was to make a cutout in the base where the sanding disc will work against the fin material. I eyeballed a spot about ¼ of the length from the end and sanded out what "looked right." After that came the easy part. I set the clamped the jig to the sander with two C-clamps, again by eyeball. Once firmly clamped, I ran some scraps from the original fin stock down the path. Not quite enough. I loosened the forward clamp just a bit and tapped it a bit closer. After one more test pass I was satisfied with the results. I was committed.

I took my four fins and ran them through on all sides. I got results I could live with.

Lessons learned:

1. A table, radial arm, or chop saw could make the job faster and prettier. They would allow for more precision.
2. The supports should not be higher than the face. I bumped my thumbs into them on more than one pass yielding less than optimum workflow.
3. The cut out should be a small as possible and should be placed no closer than 1/3 of the length from the end. The rational behind this is that on shorter fin lengths such as the tips, the fins can dip down into the cut out and you end up with a wavy bevel.
4. If you are working with wood, wear safety glasses. If you are working with more exotic material, wear safety glasses and use a respirator.
5. Move the supports inboard from the edges. Even though I drilled pilot holes, I still ended up splitting the wood. If I was a real woodworker I would probably have already known that.
6. Match the size of size of the wood to the size of the sander. If you have a 4" sander, use 4" wood. If you have a 6" sander, use 6" wood. For a 10"-12" sander, well, you probably have better equipment anyway.
7. Make sure to keep you fingers well away from the spinning disc. It will pull your fingers into the works before you even know it.

GUEST's OPINION:
"" (X.X.)