Mitered, Tapered Leg -- straight 45?

[Bill McDermott]

My brother wants a leg made to support the protruding part of an L-shaped kitchen counter. He wants it to match the modern cherry cabinets. He wants a square leg in the neighborhood of 4" at the top, tapered to something less at the bottom. I have some cherry plywood. It's easy enough to rip the four tapered pieces with a 45 degree angle. But will those miters close, or is this a compound miter? BTW, I can't get to the table saw right now to run a trial. This is just the design phase. Your experience and ideas are appreciated. Thanks, Bill

[Sam Murdoch]

Definitely not a simple 45°. It would be easier to just stack some solid wood into a 4" block and cut the angle - maybe even stack ply, cut the angle then add thin faces if you don't want to see the ply edges.

[Mel Fulks]

I think the easiest way to picture it is just pick up something with a square corner and just tilt it so that it looks like the
corner of an obelisk . Looks like 45 degree cuts to me.

[Sam Babbage]

It's definitely a compound mitre, google compound mitre calculator and there are websites that will do it for you. If it's, say, in the order of a 10 degree taper it will be close to 45, maybe 44 on the blade and 9 on the taper.

Edit: The way I conceptualise it is by imagining a four sided pyramid with a wide base that is very short, those angles sure aren't 45. Or imagine laying four triangles down to make a square, now turn that into the above pyramid, they were at 90 (0) now they are slightly less than 90 (more than 0).

I don't pretend to know the math but it seems as the angle of taper increases the angle of the edge increasingly (exponentially?) moves away from 45.

Edit 2: Or if you want to avoid compound mitres but don't want to use solid you cans make trapezoids and glue solid strips in the corners

[Mel Fulks]

I was wrong ,yes,it is a compound mitre. Counting the taper. Still say the mitre cut is 45.

[Jamie Buxton]

The rip is not a 45 degree rip. However (I've done this) if your taper is only a half inch or so in 36", the theoretically-correct rip angle is so close to 45 degrees that it doesn't matter. You can't accurately set the bevel angle on your table saw down to tenths of a degree.

...later... I found my notes. For a leg tapering from 4" square to 3" square, and 36" tall, the theoretically-correct angle is less than .1 degree away from 45 degrees.

[Mel Fulks]

I m wrong again! But if you use 45 exactly you're gonna hava hard time getting putty in any gaps. Better thin it down.

[Bill McDermott]

Thank you all. I shall proceed by experimenting. Awesome responses.

[Joe Scharle]

A 45 deg tapered cut will get you there.

[Joe Hillmann]

Another way to do it would be to put a spacer under the end that will become the narrow end that is equal to what you will be removing and then do a 45 degree rip cut. The shim underneath will cause it to be cut at the proper compound angle.

[Mel Fulks]

I agree,Joe. That's the way I saw it right away and why I did not call it a compound angle. But that method has two drawbacks: its easy ....and you don't get to use the putty.

[Bill McDermott]

Brilliant. Add one unit of taper and then compensate for it by adding another unit in the other direction. Ha! Genius. Thank you.