Qusestion on Through Mortise and Tenon

[Alan Tolchinsky]

Hi All, I'm building a small end table that calls for the top of the legs to go through the table top ending in through tenons. The top is a square as is another lower smaller shelf.

My problem is lining up the tenons with the mortises. I was going to build the bottom first then the legs will be in a fixed position. Then I would make the tenons and scribe them onto the underside of the table top and then cut the through mortises.

Do you think I'm going about this right or is there a better way. This table doesn't have an apron so I have to attach the legs to the top in another way. Any other joint suggestions? Thanks

[Dennis Peacock]

Hey Alan,

Why not do the construction you are planning on and in the order you have planned on....but....put the top of the table "top-side" down put and line up the legs (now that you have it assembled to the bottom shelf) and trace around the top of the legs. Then decide how big of a tenon you want and measure from the traces on the bottom of the tabletop and from the outside of each leg.? Or you could cut your tenons on the legs, line up centered on the bottom of the tabletop....mark and mortise out between the markings.

Just an idea.

[Alan Tolchinsky]

Hey Alan,

Why not do the construction you are planning on and in the order you have planned on....but....put the top of the table "top-side" down put and line up the legs (now that you have it assembled to the bottom shelf) and trace around the top of the legs. Then decide how big of a tenon you want and measure from the traces on the bottom of the tabletop and from the outside of each leg.? Or you could cut your tenons on the legs, line up centered on the bottom of the tabletop....mark and mortise out between the markings.

Just an idea.

Hi Dennis,

I was thinking of flipping the top as you say but then I thought when I flipped it back over that the locations of the mortises wouldn't be right. You would have the wrong mortise lined up with the wrong tenon after flipping? Make sense? I don't know.

The last thing you say makes sense to me but seems to demand perfection in the procedure to turn out right. I guess I'll have to try it to see and maybe make some firewood. :)

Thanks for your ideas. Alan

[Doug Shepard]

Seems like it might be a little easier to cut the sq. holes in the table top, then clamp it in place on top of the base unit and trace through the holes to put layout lines on the top of the legs. Just my 2 cents.

[Jim Becker]

Or...you could cheat and just make the "through tenons" an inlay on the table top with non-through tenons engaging the bottom of the top, but that should be the last resort since there is great value in learning how to locate things properly for a true through tenon. ;)

[Glen Kenney]

Hi Dennis,

I was thinking of flipping the top as you say but then I thought when I flipped it back over that the locations of the mortises wouldn't be right. You would have the wrong mortise lined up with the wrong tenon after flipping? Make sense? I don't know.

Alan

I think you misunderstood Dennis. He's saying to lay the top on your assembly table with the top-side down and then turn the assembled bottom half over on top of that. It would be just like turning the entire assembled table upside down. Then when you scribe for the tenons, you would be scribing each mortise for it's matching tenon.

Or, as my wife says, I may have the whole thing wrong and don't know squat! :(

Glen Kenney

[Alan Tolchinsky]

Hi Dennis,

I was thinking of flipping the top as you say but then I thought when I flipped it back over that the locations of the mortises wouldn't be right. You would have the wrong mortise lined up with the wrong tenon after flipping? Make sense? I don't know.

Alan

I think you misunderstood Dennis. He's saying to lay the top on your assembly table with the top-side down and then turn the assembled bottom half over on top of that. It would be just like turning the entire assembled table upside down. Then when you scribe for the tenons, you would be scribing each mortise for it's matching tenon.

Or, as my wife says, I may have the whole thing wrong and don't know squat! :(

Glen Kenney

Hi Glen,

O.k. that would make sense to me.

So if you wanted to attach the four legs to the top without through tenons how would you do it? This is not as elegant as tenons but I was thinking of pocket screwing ( don't tell anybody) some 1x wood between each pair of legs and then screwing the top to this 1x wood. I don't have an apron on this table. Any other ideas greatly appreciated. Thanks Alan

[christopher webb]

take a look at my thread " new table " it has through ten. see if that is what you are talking about

[Norman Hitt]

Hi Glen,

O.k. that would make sense to me.

So if you wanted to attach the four legs to the top without through tenons how would you do it? This is not as elegant as tenons but I was thinking of pocket screwing ( don't tell anybody) some 1x wood between each pair of legs and then screwing the top to this 1x wood. I don't have an apron on this table. Any other ideas greatly appreciated. Thanks Alan

Alan, it's not that hard to make the through tenons and corresponding mortises if you use this procedure:

1. First, Cut the tenons on the ends pf the legs, and make them to fit snugly into a mortise, that is cut with a 1/4" router bit, (upcut spiral bit preferably). (make a test mortise on a piece of scrap to check the fit of the tenons on the legs)

2. From the plans, get the dimensions and cut a piece of MDF or plywood that would exactly fit inside the Legs at the top, and clamp it in place between the legs, then clamp the lower shelf in place also.

3. Lay the table top, topside down on your workbench and place a mark at exactly the midpoint of each side and then connect the marks at opposite sides of the top.

4. Turn the clamped up legs upside down on the top, and mark the center point along each edge of the MDF and connect the marks to the opposite sides with a line, as well as a vertical line on the mdf edges at the marks.

5. Align the marks at all 4 edges of the MDF with the lines below on the table top, and this will center your base to the top, then temporarily fasten it in place with a couple of screws.

6. Scribe carefully around the leg's tenons onto the table top.

7. Remove the base leg assy from the top, and with an edge guide on the router, set it up to make the mortises into the marks.

8. With a chisel, square up the corners from "Both the Top and Bottom", inserting the legs and checking the "Fit" as you go to make sure you have a good fit.

Good Luck

[Jerry Olexa]

Accurate measurement and placement of the areas to be mortised should make it work. Allow for the offset of the tenon vs the OS Dims of the legs and transfer to the underside of top. Take your time and measure carefully and you should be pleased..I would use a plunge router w a jig in a case like this.

[Dennis Peacock]

He's saying to lay the top on your assembly table with the top-side down and then turn the assembled bottom half over on top of that. It would be just like turning the entire assembled table upside down. Then when you scribe for the tenons, you would be scribing each mortise for it's matching tenon.
Glen Kenney

CORRECT!!!! Sorry if my wording isn't always clear as bottled water....I'll try harder next time to be more clear. :rolleyes: ;)

[Alan Tolchinsky]

I saw this in a store and really liked the lines and simple construction. The curly maple used through out didn't hurt either. Now I'm going to read the help given to me here. Thanks a million.

[Alan Tolchinsky]

Accurate measurement and placement of the areas to be mortised should make it work. Allow for the offset of the tenon vs the OS Dims of the legs and transfer to the underside of top. Take your time and measure carefully and you should be pleased..I would use a plunge router w a jig in a case like this.

Hi Jerry, These legs just go straight up so do you still need offset? Thanks Alan

[Glen Kenney]

Alan, how about biscuits in this situation? They would basically serve like loose tenons joining the end grain of the legs to the long grain of the top.

Glen

[Alan Tolchinsky]

Alan, how about biscuits in this situation? They would basically serve like loose tenons joining the end grain of the legs to the long grain of the top.

Glen


Glen, That's an interesting idea. I'll have to ponder it but it seems like it would work. It could get a little tricky lining up the biscuit slots from the top to the leg. Thanks Alan

[Keith Christopher]

alan,


Geometrically speaking, if you have a symmetrical rectangle or square the positions of the marking will not change with the opposite sides. Or in other words if you have a rectangle or square and you flip the piece and mark then cut you will have the layout correct and it will fit. so if you have all the thru tenons 1" in from the corners and each side; top or bottom, side to side, they will all be the same. that being said, you must first make sure everything is square, and if you're like me, they're often a little off. ;)

[Mark Singer]

Just make the base and top seperately and scribe the legs on the top and cut them out....using a router or chisels...let the leg tenons through...wedge and trim the excess