How to match apron end to round leg?

[Andrew Duncan]

The triangular tables I'm building have round legs. I'd like the top portion of the leg to be about 1 3/4" diameter. How can I match the apron ends to the round profile? I've thought about using a spindle sander, but that means the leg diameter has to conform to available spindle sizes (say 1 1/2" or 2".) Any other methods that anyone has used?

[Jamie Buxton]

If you're asking how to make a rounded corner on a table top, here's two suggestions. If you're doing just a couple corners, draw the line you want, cut just to the outside of the line with a saber saw, and clean up with a belt sander. If you're doing several corners, you could make a template, and cut the curve with a template-guide guided router.

I have don't understand what the diameter of a spindle sander has to do with the issue. It might affect the diameter of a concave curve, but you're cutting a convext curve.

[George B. Tracy]

Is there a reason why you wouldn't want to cut "flats" on the round portion of the leg where you will join the apron? Are you tenoning the joint?

[Frank Drew]

Jamie, I might have misunderstood the question, but I think Andrew wanted to know how to mate his rails (aprons) to the curve of the legs, in other words, to make the end grain portions of the horizontal pieces match the convex curve of the legs (i.e. concave to convex).

Andrew, what kind of joint do you plan to use to attach the rails to the legs? You can carve out the hollow on the ends with gouges; since the exact interface of apron to leg really isn't seen the work doesn't have to be perfect. George's suggestion might be the easiest; you can scribe two lines on the legs for each joint while still on the lathe (using the tool rest to guide the pencil), saw a series of kerfs almost to the lines and clean up and refine the flats with chisels and a block plane.

[Andrew Duncan]

The aprons will be attached with loose tenons to the legs. Frank, you're right that the fit of the joint only will be seen from the bottom of the apron, but I'd prefer a tight match. George's suggestion may end up being the best though aligning the flats between the legs would take some thought. Assuming I can get the alignment right, maybe a tenoning jig at the table saw might be another way to cut them. Thanks for your suggestions and any additional thoughts you might have.

[Chris Padilla]

You may wish to complete the apron to the legs joinery BEFORE the legs are turned round, if possible.

Then turn the legs to a dimension matching a spindle sander and jam the apron's end into it until you get a tight match. However, if you don't want to be hamstrung on available spindle sizes, you can consider making your own spindle sander size turning your own or using a dowel and gluing/wraping on your own sandpaper....

[Mike Henderson]

There's the question of how to clamp the leg so that you can cut the mortise in the right place and in the proper direction (since may not be directly towards the center).

But assuming you get the mortise cut properly, I'd then put the apron rail against the leg (and if you're going to use a loose tenon, put the tenon in) and mark with a marking knife exactly where the top and bottom of the apron hits.

Then take a chisel and cut the leg flat at that point. Go slow and make sure the cut at the top and bottom is tight. While you can do this and have it tight fitting all around, it really only has to fit tightly where you can see the junction. Except for woodworking pride, you don't have to have a tight junction on the inside where it can't be seen (but try for it).

Mike

[Joe Scharle]

I've only done this once, but what I did was slot the top of the leg and bridle joint the apron. The whole apron is the tenon.

[Andrew Duncan]

I'll use a slot mortiser to cut the mortises, so I don't foresee any problem there. And, of course, Chris is exactly right. I can easily match whatever diameter I choose for the legs by turning a matching spindle. So simple, why didn't I think of that?

[Greg Jurrens]

Bore the stretchers with a forstner bit the same diameter of the leg and then use loose mortise and tenon joinery.
Greg

[Cliff Rohrabacher]

Inset the entire Apron just a hair.

[Greg Hines, MD]

Most often I have seen this problem addressed with sliding dovetails or tenons. Chris is right that you need to form whatever joints you are going to use before you turn the legs round.

Doc

[Richard M. Wolfe]

I'm with George on this. If you are going to turn legs for the tables leave a shank on the leg tops to attach the apron, or if the legs are already round cut flat areas at the top. Easier to fit a flat cut than a curved....regardless of angle.

[George B. Tracy]

Andrew I doodled my perception of what you're trying to accomplish to think it out a bit. I made the drawing kind of quick to get some ideas. I drew it with 1 3/4" diameter legs and 3/4" aprons. In order to "draw" it out on graph paper I came out with similar angles for the top flats but different for the 3rd leg. It appears that the 90 degree angle of the square leg would need to be "centered" between each apron in order to have the same angle 60/120. It also seems that the flats would have to be shallow in order to maintain the "round" of the leg meeting the flat of the apron. The drawing would definitely need some tuning up to be accurate but this was what I was thinking yesterday.

[Jim Becker]

What Chris said...just like in chair making, when you have an end result that will have curves and other complexities, do the joinery prior to shaping. For your legs you'll want to be sure to calculate where the "flat" shoulder will be after turning.

There are two ways to create the shoulders in my mind:

1) construct a jig to hold the legs while you use your bandsaw to create that flat. You'll want another jig/cradle to hold the workpiece while you route the mortises

or

2) create a jig that sits on the ways of your lathe to support your router. You can then use a router to create both the flat and the mortise along the lines you calculate for the apron positions. A mortise/tenon arrangement that actually goes to the top of the leg will be easiest to create this way. You will also want to pre-turn the legs proud of the final diameter (with the final diameter drawn on the tailstock end) to make the marking easier and eliminate any contention of "corners" that square stock would bring to this method. BTW, this is the same way folks make things like Shaker style candle stands, etc.

[Andrew Duncan]

George, that's indeed what I'm doing. I turned the legs to simple cylinders, marked the centerlines for the mortises by mocking up the legs in their final position and then cut them on the slot mortiser. The corresponding mortises on the apron ends were also cut and I used a spindle sized to match the leg diameter to create the concave face matching the legs. I'll put the legs back on the lathe to taper them before completing the base.

Thanks again for everyone's advice.