How to cut beveled edges for trapezoidal boxes

[mthomas]

Assuming that you were constructing trapezoidal boxes with with gently angled sides (say, 10 degrees or less)... is there any practical way to produce cuts with the appropriate beveled edges for mitered joints? I can't think of a way, but I'm interested in anyone else's opinion.

Thanks!

[billp]

I'd opt for the table saw myself, but if you could do the math for your project there are people who will grind custom router bits...

[beacon14]

I would cut the parts to shape first, with edges square - the SB would come in handy here. Then I can show you how to set up the tablesaw to bevel those square edges to a perfect knife edge without changing the shape of the part. The only requirement is that all your parts be the same thickness - otherwise you'd have to tweak the saw setup for each thickness.

[gerald_d]

The sides of the box do not have to lie flat on the table when you bevel them. Had some joy using standard cutter angles and wedging the part edges up on jigs.

[rhfurniture]

o/hand planer

r

[mthomas]

So I'm not missing something here (which I thought I was) - there really is no easy way to do this completely on the SB without the use of custom-ground bits to match the appropriate angle.

The table-saw idea is one I had considered - might give that one more thought, but I think I'll look into the custom bits first.

Thanks!

[gerald_d]

You might have missed what I tried to say. If you have a small square box with 10 degree "flared" sides, you can lay the sides at 10 degrees to the table top by resting them on scrap, and then use a standard 45 degree bevel cutter. For small variations from standard cutter angles, I find it easy enough to "wedge" smallish parts at an angle to the table surface.

[mikejohn]

On the other hand, you could easily make a jig on the shopbot that would hold your pieces at any angle.

..........Mike

[mthomas]

The jig ideas are interesting, but I have serious concerns with introducing errors because of the part's orientation in 3d space. Also, you could only machine one edge at a time, requiring a lot of hands-on time to reposition.

I'm far more inclined to pursue the idea of a custom-ground bit with the correct angle.

[gerald_d]

The small square box that I mentioned above:


4991

One clamp per piece, a piece of scrap batten runs under all four sides giving the side slope angle. The movement of the SB is not at a slope - one pass of 45 bevel cutter cuts two adjacent sides. Of course there are limitations, but it can get around custom bits in some cases.