Joinery that allows slab console table to be disassembled?
Please see attached photo.
The slab top is 1 1/2 ” thick red oak. The base and supports are mesquite I salvaged from a tree in my yard. After epoxy fill in the cracks I plan a symmetrical cutout approximated by the cardboard. The mesquite legs will be ~4″ wide by 1.75″ at the top and 8″ by 1.75″ at the bottom.
My first thought was to use 3/8″ threaded rod and epoxy to connect all the components in 4 places at each joint for maximum strength. Ref Fine Woodworking #285 Nov/Dec 2020, Versatile Option for Leg Joinery by Timothy Coleman. I’ve used this with great results on a heavy 2″ mesquite slab with robust maple legs in the past.
But in considering other options that would make this table easier to move I’ve been thinking about using 1″ inserts and bolts to attach the base, and either a figure 8 type top fastener clip (but fabricated larger than normal and perhaps engage inserts in the legs), or a hard maple cross piece glued and screwed into a notch on the end grain leg and then bolt into the top using 1/4″x20 furniture bolts.
However, because I’m relying on end grain in both top and bottom of the legs I’m not sure of the holding power given there are only two narrow supports for the top.
Any insights you might have are appreciated.
I should also mention that I originally chose the epoxy threaded rod method over a mortise and tenon for expediency and my lack of practice on large M&T joinery may leave a weak joint.
Thanks Kevin
Replies
Look up "keyed through tenons". I think you might be looking for a trestle table design. The use a trestle at each end and a beam that connects them together.
Thank you for the response and I apologize for my poor description. The sketch below might help to see the construction. I did get some 5/16" inserts and tested them on the end grain and they seemed to hold quite well. I think that is a solution for the bottom of the legs whose width runs parallel to the top and base.
The top I am considering four figure 8 table top fasteners per leg but because they would attach to end grain on the let top I'm not sure the strength would be enough. Another option is a shaped angle bracket made out of wood, this would give a broader platform for the top to sit on but would not look as clean. I guess I'll do some experiments to see how the figure 8 tabs work out.
Hopefully the pieces on each end have more width to them than the sketch shows. Also the top doesn't seem stable with the legs meeting near the center perhaps long rib 4-6" deep attached with a bridal joint. Also a beefer base would in order. My 2c.
I don't have an answer but I do think that designing furniture to be easily disassembled and moved is something that would be worth discussion in future articles.
I don't quite understand your design and what you're looking for. I don't know if you have access to a Domino, but Festool makes some high quality knockdown fasteners that work with it in place of the floating tenons. Not like Ikea, much sturdier and easier to use. That's an option.
Almost all table designs involve some sort of free-standing solid bottom frame to which you can easily attach any top without worry of seasonal movement or tipping. Looking at your sketch, I think you should consider starting over.
Please see the photo of the clamped up table. For each leg I went with 4 5/16" bolts through the bottom into inserts in the end grain.
The base is 1 3/4" thick and legs are 1 1/2" thick. The bolts make the legs and base very rigid. The base is 40" long and weighs 32 lbs vs the top is 80" long and weighs 20 lbs. The width of the top is typically around 10 inches. So although it's not as stable as other configurations would be I like the look and may add an adjustable security bracket to allow it to be connected to the wall. Note the shape of the legs keeps the mass of the base lower which also helps with the stability.
The top I've decided to use 1/4-20 inserts through 4 wooden 90 deg brackets with slots for movement - glued and screwed to the face of the legs. Not as clean looking as I had hoped for but it fits the overall chunky design and provides a better platform for top to sit on. I looked at flat slotted metal brackets inset into the top as an option; but I have the wood on hand.
Thank you for the comments.
I guess what you're doing here is trying to have a center pillar of a sorts. If you are, from this picture, you have a couple of major problems. The very bottom base is long and narrow providing support the long way but very little the cross way. It's going to fall over.
It appears that if this is a central pillar you have long overhangs. Essentially, the long part of the top is acting as a cantilever. This puts tremendous force on the leg/piller connection.
Consider making the base wider by half. You could do this with an ovular design for a graceful shape.
To support your top I think what you could try is the combination of a loose tenon and a keyed through mortice. Cut a large as you can make tenons loose. Cut tight fitting mortices in the underside of the top. Glue tenons into mortice.
Can a vertical mortice in each leg to receive the tenon sized to tightly receive the waxed tenon. Drill a cross hole through the leg and tenon. Secure with a wooden pin.
The challenge is going to be to get the tenon to stay in the underside of the top. It's going to want to dry out and the glue would fail. Possibly use epoxy.
Even with all of this you're still pushing what this leg arrangement can support.
I'm pleased that it turned out to be very solid. The tipping point around the base is 12 deg - comparable to my magazine rack end table with lower shelf at 15 deg. I thought I might have to put extra feet on the corners of the base to extend it's width. I can load up the cantilevered ends with 6o lbs of weight without any wobble. Top is connected with 4 slotted 6" metal plates recessed into the top and tied to the legs and top with 1/4-20 inserts. Each leg has 4 5/16" inserts and bolts attaching to the base, it's rock solid.
The base and legs have 2/3 the mass of the top which helps keep the center of gravity low, but before our xmas party when we have toddlers running around I'll probably run a discrete bracket to the wall to keep it safe, same thing I do for bookshelves. Note the design was constrained by the salvaged wood I wanted to use up.
I appreciate all your comments and thoughts it helps a great deal to be able to bounce ideas off others. I'll try to have better explanations in the future.