Tapered miter?

Jan 10, 2011 19 Replies

I am designing a table lamp that is built as a four sided column or box but I want it to taper from bottom to top. I'm sure I can do some



3D CAD and figure out the miter but wasn't there a table or formula somewhere that provides the miter angle.

I know it will change very little. I am doing a 4 sided box that will taper at maybe 5 or 10 degrees. I think the 45 miter cut will actually change by a degeree or less but I would like to get it precise for a clean fit up.


Here's one.

formatting link
are many on the web, just google "compound miter" Art

The miter will remain 45=B0. You can do your taper cut on the table saw with the blade at 45=B0 OR do your taper cuts, then use a chamfer bit on your router for the miters along the lengths.

Sonny

44.8 degrees for a 5 degree taper, 44.1 for a 10 degree.

formatting link

Perhaps I'm missing something here... but why could you not build it as a

*straight* column (eliminating any issues with compound miters), then taper it after it's built?

You might think so but it isn't true.

I suppose you could but 5 degrees x 13" tall = 1.1374" offset so I would have to start with some pretty thick wood.

There are other times when you might want to show the rays from qtr sawn oak, and you might do the miter for that purpose.

So there are reas> >> I am designing a table lamp that is built as a four sided column or

Yup, center lines of the tails and pins should be level if you want them to look right. Build a quick full scale model and pencil the joints on, then copy when all looks right. Cardboard and paper packing tape are your friends.

Just a curious question, but how does one set a blade angle of something like 15.6 or some of the other very precise angles required in these calculations.

I have some very accurate setting tools but none would allow a blade angle that fine.

Having never built anything with a compound angle, I'm really curious.

LeeValley has the answer. This is one way to do it-

formatting link
have it and it works well.

I got this one, the protractor, and it works well. I used to physically match angles, then tried a regular t-bevel, but this is even easier and much more precise. I can transfer numbers to the miter saw from it, not just physical angles. (and it's only 1/2 the cost of the tiltmeter.) I ordered it during one of the free shipping sales.

formatting link
United States of America is the greatest, the noblest and, in its original founding principles, the only moral country in the history of the world. -- Ayn Rand

The other guys have the correct answer but I don't typically get that precise. I am more interested if it is a few degrees off. I always do test cuts on this type of stuff so if I see 44.333 degrees, I know I need to start cheating towards 44 to get a sweet fit up.

Look for this and get it at 1/2 the price.

formatting link

15 1/2 degrees should be close enough.

I'll be putting that on my LV list Thanks

$30 Electronic Tilt Box. Works in 1/10's of a degree.

Or if you have an accurate miter gauge you cut a scrap triangle to that angle and use it to adjust the tilt on your blade.

There's also a protractor that uses the same principle:

formatting link
setting your miter gauge.

I've got both and they're great. But be warned that the protractor, regardless of what the ads say, cannot be locked down. It can be tightened to where it won't flop around, but in appreciable pressure will move it. I checked with the company and they confirmed that, but their ads still say otherwise.

=A0I checked with the company and they confirmed that, but their

Sometimes it boggles the mind how engineering can come so close to a perfect solution and yet not address some basic yet fundemental flaw.

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required