Breadboard End repair question

[Gary™]

Friend at work is buying an old mahogany dining table set where the breadboard end is detached. I looked at the picture he showed me and the tenon on the table appears to be broken off inside the breadboard end. It looks like it was glued all the way across before (yikes - someone never heard of wood movement).

I'm thinking how I'm going to fix this (yeah I'm going to help him). I'm thinking of ways I could fix it. Not to hard to clean up the breadboard end and cut out the old tenon piece.

I can't cut a new tenon on the table since the table has some beading on the top and I'd mess up the spacing. I'm thinking of trying to use a loose tenon and just cut a groove in the table with my router. Use some walnut dowels (or other contrasting wood) to hold the breadboard and let the dowel ends show from the top; do the other end to match unless it's ready to fall off too.

Any better ideas?

[Cooler]

A hidden spline will keep alignment. Just glue the middle 3or 4 inches of the spline and let the rest float.

It is just a thought. I've never tried it. But it sounds pretty easy with a router and a spline cutter.

[jteneyck]

Yeah, cutting mortises for loose tenons sounds like a good way to go about it. Use an edge guide with your router and it should go smoothly. I would put the dowels in from the underside, however, unless you specifically want that decorative element on top. It would be faster and easier to do it on the bottom and any little oops won't show. Be sure the tenon has the grain running parallel with the table top. Glue it into the mortise in the table. Drill the holes into the breadboard for the dowels, and then be sure to elongate the outer holes so the tenon (tabletop) can expand/contract. You can glue the center dowel in, but glue the dowels near the ends only in the outer hole of the breadboard. You can even put a little wax in the outer tenon slots before assembly to make sure no glue bonds to them should any get in there. Hope that makes sense.

John

[Gary™]

Thanks, it makes sense. I have a router slot cutter bit with different guide bearings I use for biscuits and figured I'd cut the slots for the spline/tenon with it. Is there is a specific depth (tenon length) I should be shooting for?

[barnowl]

jteneyck said:

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Yeah, cutting mortises for loose tenons sounds like a good way to go about it. Use an edge guide with your router and it should go smoothly. I would put the dowels in from the underside, however, unless you specifically want that decorative element on top. It would be faster and easier to do it on the bottom and any little oops won't show. Be sure the tenon has the grain running parallel with the table top. Glue it into the mortise in the table. Drill the holes into the breadboard for the dowels, and then be sure to elongate the outer holes so the tenon (tabletop) can expand/contract. You can glue the center dowel in, but glue the dowels near the ends only in the outer hole of the breadboard. You can even put a little wax in the outer tenon slots before assembly to make sure no glue bonds to them should any get in there. Hope that makes sense.

John

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+1

I'll only add that the dowels don't have to go through to the top face...and do all the work/repair from the underside.

I've done breadboard edges with hidden dowels... they go into the upper "meat" above the tenon, but not deep enough to show on the surface.

Again, installed mostly, and just the last bit of dowel gets glued, then cut flush with the underside of the table top.

Hope that makes sense.

One example:

[dg152]

jteneyck said:

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I would put the dowels in from the underside, however, unless you specifically want that decorative element on top.

John

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John, the dowels are a good idea. I just did it on what sounds like a similarly designed table. However, I would suggest inserting the dowels from the top. There's a chance - especially if the dowels are tight in the hole - that there will be some tear out as the dowel comes through the other end of the hole. I like your idea of a little wax on the dowels with glue on the ends only.

Gary, I think you've got the right idea and you've gotten some good suggestions about how to go about completing the project. Post some photos of the before and after. This is something we can all learn from.

[Gary™]

Yup I'll post pictures. It'll be when it warms up as I don't have much heat in my shop and it's darn cold out there.

Thanks everyone

[Splinter Puller]

I'd route out the breadboard end and also the top and as other have suggested use a loose tenon. I would however not use a spline. I'd use a tenon of the same species as the top and with the grain running the same as the top and glue this in solid to the top. Then,n mount the breadboard following traditional methods... pegged or glued in the center (or front) allowing movement on the other direction(s)

[AgGEM]

You might find this video on the subject, interesting:

https://www.youtube.com/watch?v=Ad-Qy5WS23E

Ag

[Gary™]

Well my friend won his bid on the table and picked it up. He brought the breadboard in so I could look it over. Here are some pictures of it as is.



It looks like the tongue isn't broken but was build very short all the way across 1/8"+. There are holes on the ends of the breadboard where it looks like someone tried to put nails into the top to hold the breadboard on the top. Obviously somebody tried to glue it all the way across before too.

I measured the groove cut in the breadboard for the tongue and it's only 1/8" thick and ~1/8" deep.

So to fix this I'm now thinking of cutting 5 mortises into table top and glueing in loose tenons cut long grain from mahogany. The cutting matching mortises into the breadboard allowing space for wood movement on the outer four. Then peg them (enlarged holes on the outer 4) from the bottom but not going all the way through to the top.

So my questions are:
1. Since the existing tongue and groove is ~1/8" thick and deep, is that enough or do I need to make it thicker ~ll the way across?
2. Is a 1/8" loose tenon thick enough or do I need to cut them thicker (say ~1/4").
3. How deep should I cut the mortises for the loose tenons?