Cutting a rabbet on curved mirror frame
I’m making a mirror frame with a curved top piece. No problem cutting rabbets on the 2 sides and bottom because they’re straight pieces. Besides buying a piloted rabbet router bit, any suggestions on how to cut the curved rabbet for the top piece?
Do you want cheep or interesting and versatile ?
Well . . . you have to spend even more money for my solutions but they are fantastic tools to have . . .
You can attach a curved chunk of wood to the bottom or use their axillary fence.
This also will do the job and has a short curved fence
Orrrr . .
you could make a little plane from wood to do the job ; see " carriage planes " which tend to have curved soles or sides.
You're right, these are more expensive options. So far, the rabbet router bit seems like best overall solution. I haven't been able to figure out how to set up a template to use with, say, a pattern bit that would do the job without having to buy a specialized bit.
May Not Need a Curved Rabbett
Depending upon the depth of your arch (chord length, radius and altitude of the arch), you may be able to saw a straight rabbet in the frame. This implies a gentle arch. The mirror can also then be square cornered. The back is not seen, I assume.
And by extension, even a hlaf round top rail can be made in 3 or 4 sections, each with a straight rabbet, to accommodate the mirror.
There is always lots more than one way to do about anything.
You can make the rabbit before or after assembing the frame. If you use a pattern trim bit with the bearing near to the shank rather than on the bottom - the bit will follow any template cut out you tack down.
With a pattern trim bit, the bearing's diameter is the same as the cutter, so how can I create a template that will let me just cut in the workpiece to leave a "ledge" (the rabbet)? It seems like I'd have to have a bearing that's smaller than the cutter--and that's what the rabbet bit has.
can't do sections
From an aesthetic point of view, I wanted the top piece to be whole so the grain pattern flows naturally. I'm working with leopardwood which has a striking grain and doesn't come in a wide board. The curved top piece is about 14" across and has a maximum radius to the outside edge of 5 1/2 " (the width of the frame is about 2"). So far the rabbet bit still seems like the best approach.
Personally, for the little bit of money it costs rabbeting bits are a great investment. You'll use one all the time. That said, with just a little bit more work, a template, a straight bit and a guide bushing on your router, or even the router table if you can set up your table with one, will accomplish the same thing.
I bit for the rabbet router bit and it was well worth it. (Whiteside rabbetting set, 1/2" shank, with different size bearings, $50 on Amazon) The cutter is so sharp that I was able to cut a 1/4" by 1/4" rabbet in one pass. Just ease into the cut to get the bearing in contact with the workpiece and run it through.
Thanks, everyone, for your responses.
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