Need advice - lock miter

[Ken Weaver]

I'm getting started on a project to build 3-4 misson style end tables. The legs will be 2" square. At present I'm thinking of gluing up 3 3/4" slabs to get the thckness then plane to the final 2"x2" size. Came across the lock miter bit at MLCS (below) and began to think about using that to make the legs. That approach will require 4 slabs of oak instead of 3, but should give a better grain face all the way around. The question I have is, if I use the lock miter, that will create a hollow space in the middle of each leg. If I do that, will it effect the strength of the mortise and tenon joints for the rails? I was also considering through tenons for some of the rails but with the hollow space, I'm afraid the loss of glue surface may make the tables less strong. Am I off in left field to worry about it?

[kwgeorge]

I really don’t think you need to worry about strength all that much as to what you are talking about doing. Seems like you will have a lot of surface area for glue. Don’t think I would do the locking miter though instead if I were worried about extra support for the joints I would just do a 1/8” spline cut in the middle of the 45’s and insert splines. As to the Mortise area you could always add a piece of wood to fill that gap when you assemble. I also think you will be happier with the results of the 4 pieces boxed rather than the pieces face glued, I have done both and I know I would be.

[LCHIEN]

I really don’t think you need to worry about strength all that much as to what you are talking about doing. Seems like you will have a lot of surface area for glue. Don’t think I would do the locking miter though instead if I were worried about extra support for the joints I would just do a 1/8” spline cut in the middle of the 45’s and insert splines. As to the Mortise area you could always add a piece of wood to fill that gap when you assemble. I also think you will be happier with the results of the 4 pieces boxed rather than the pieces face glued, I have done both and I know I would be.

ken's got some great points. I think definately I would consider his suggestion for the 45's with splines. Easier setup, same for all foour legs.
I haven't done them but I have looked at the instructions and thought about 45° lock miters, the setup is tricky/critical and on the last cut the wood will be riding on the 45° edge.

[Ken Weaver]

ken's got some great points. I think definately I would consider his suggestion for the 45's with splines. Easier setup, same for all foour legs.
I haven't done them but I have looked at the instructions and thought about 45° lock miters, the setup is tricky/critical and on the last cut the wood will be riding on the 45° edge.

What should I use for a spline material? 1/8" hardboard work?

[LCHIEN]

What should I use for a spline material? 1/8" hardboard work?

Anything that's 1/8", I guess.
Is 1/8" hardboard exactly .125" or is it like plywood and undersized?

You might rip some pine to the exact width needed.

[kwgeorge]

In reality you want the spline to be a bit undersized so the glue has somewhere to go. I would use the same wood that you are making the legs out of. Just rip some strips on the table saw and call it good!

[Tom Miller]

I'll throw in another vote for the general method that Ken mentioned, with the caveat that I haven't actually done legs that way. I have done the glued-up slab method, though, which worked out fine for that particular project, but not as good as this method would look.

Couple points, though: I think the glue lines need to stay at the corners to look good, so if you're going to taper, you need to taper all four sides the same.

Second, true splines have their grain going cross-wise to the grain of the wood they're joining, for strength (or, they're made of ply). But I don't really thing you need that extra strength; you need help in alignment, so long grain strips would be fine.

One other point: would you show edge grain on all sides, or face grain? I suppose it depends on the species, but I'd probably go with edge grain.

Regards,
Tom

[RHunter]

John Lucas over at woodshopdemos.com did a write up doing exactly what you are suggesting.

Edge Grain Table Legs

Of course setting up the Lock Miter is, well, tough. I've burned up about 6bdft of cheap BORG Poplar to experiment with, and still haven't gotten it right.

Of course those that use it say it gives a very strong joint, very nice tight joint- but getting there is the hard part.

I almost rank this with tweeking my technique to use my HF Dovetail Jig right. I can get it, but it takes ALOT of scraps to make sure before I even get the project wood near it...

[Ken Massingale]

Without commenting on you being out in left field, my friend Ken 1 , I agree with Ken 2 about using 45's and a spline for this application. IMHO the lock miter is a fine, strong joint but is fussy. I have the MLCS LM bit if you want to run over and try it. You may get the setup dead on right away, you may be up all night trying. I use it more for drawers than anything else, and that's not very often anymore. I used it once for legs for a display case, 48" long stock, and will never do it again. Any slight deviation in the position of the stock against the bit will result in a bad joint.
Yell if you want to play with the LM bit, heck, yell anyway!

Ken 3