# 15 degree mortise and tenon



## darsev (Feb 3, 2012)

I am wondering if anyone has an easy way to create a mortise on an angle. I made a table a while back with the legs on a 15 degree angle. Tops of the legs were set into a mortise in the table top so that the full size of the legs were the tenon. With a frame at the bottom (magazine rack) stopping the legs from splaying outwards and slotting into the mortise at the top, it is a very solid and stable design. However it was very time consuming to cut the mortises manually with a hammer and chisel. 

I am wondering if anyone else has done something like this, and has found a less time-consuming way. I thought of tipping the router on a 15 degree angle, but then the bit wouldn't reach far enough. My drill press is pretty small and I wouldn't be able to hold the table top securely on it, not even flat.

Any ideas?

thanks,
Darryl


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## Cherryville Chuck (Sep 28, 2010)

I have a 16 1/2" Delta drill press so I bought the mortising attachment for it at a wood show for about $65. I haven't had a need yet to use the router for one but it could happen. As far as not having enough table to do that, I think that I could rig up a sawhorse/support frame in about as much time as it would take me to make a mortising jig for the router. That would be my way to do it most likely.

Did you drill holes first and then chop out the remaining waste? This is a pretty common way that it was done in olden times, You can make a drill guide out of a block of wood on your drill press by drilling a hole at the 15 deg angle through it. A 3" thick block works well. Just watch your orientation when you set on your work. Drill the first hole carefully until you have the depth right and then mark the drill with a magic marker.

You could angle your tenon 15 deg and put in vertical mortices which might be the easiest.


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## bobj3 (Jan 17, 2006)

MLCS Horizontal Router Table

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darsev said:


> I am wondering if anyone has an easy way to create a mortise on an angle. I made a table a while back with the legs on a 15 degree angle. Tops of the legs were set into a mortise in the table top so that the full size of the legs were the tenon. With a frame at the bottom (magazine rack) stopping the legs from splaying outwards and slotting into the mortise at the top, it is a very solid and stable design. However it was very time consuming to cut the mortises manually with a hammer and chisel.
> 
> I am wondering if anyone else has done something like this, and has found a less time-consuming way. I thought of tipping the router on a 15 degree angle, but then the bit wouldn't reach far enough. My drill press is pretty small and I wouldn't be able to hold the table top securely on it, not even flat.
> 
> ...


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## neville9999 (Jul 22, 2010)

darsev said:


> I am wondering if anyone has an easy way to create a mortise on an angle. I made a table a while back with the legs on a 15 degree angle. Tops of the legs were set into a mortise in the table top so that the full size of the legs were the tenon. With a frame at the bottom (magazine rack) stopping the legs from splaying outwards and slotting into the mortise at the top, it is a very solid and stable design. However it was very time consuming to cut the mortises manually with a hammer and chisel.
> 
> I am wondering if anyone else has done something like this, and has found a less time-consuming way. I thought of tipping the router on a 15 degree angle, but then the bit wouldn't reach far enough. My drill press is pretty small and I wouldn't be able to hold the table top securely on it, not even flat.
> 
> ...


Darryl it real depends on how many joints you are going to do, if you are just going to remake the table you did make before and you are only going to make the four joints needed for that new table, then there is no point in buying or making a jig where the cut can be done with a router, by the time you made a jig then the four joints could be done by hand, without knowing how thick your side rails will be then you could consider using a set of two or three heavy dowels as drilling the holes on an angle is easy to do and there are some very spectacular glues that will not break so PM me if you want the information about them, if your side rail is not thick enough for a 19mm dowel then you could glue a full width block that is at least 50% longer than the length of the dowel, on the inside of the rail to allow the heavy dowel to fit as your leg should be thick enough to accept it. A Festool Domino Machine can do that type of joint as a loose tenon but that Lamello type machine is $2000au so not worth buying unless you need it to do a lot of commercial work, so with the correct glue then the thick heavy dowel will be very strong and I would be quite happy to do that type of dowel construction professionally but no Cabinetmaker would do any mortise where it was at an angle, they would do the mortise square to the leg and they would do the tenon at an angle so. 

There is another way, and that is to do a full width tenon on the end of each rail and cut the tenon shoulder where it meets the leg at your 15deg angle but leave the tenon longer for now, now, do the mortise into the leg at a normal 90deg and run it down close or very nearly at the bottom of the rail but stop it further away from the top, now cut the haunches at the top and the bottom of the tenon to suit the angled leg and this is what is called an angled haunched mortice and tenon and as the mortice in the leg is square to the leg then that mortise can be cut with a normal router cutter, I would set it out full size on paper before I cut it so I would know how long the tenon needed to be and what its shape would finish and if you don't understand then I could do you a drawing and post it if you want me to, either way, heavy dowels or an angled haunched mortice and tenon will work and you will not need to buy any nasty expensive jigs. NGM


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## Bradleytavares (Feb 25, 2012)

I'd like to learn more.


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## bobj3 (Jan 17, 2006)

http://www.rockler.com/product.cfm?page=11367&site=ROCKLER&filter=trend jig

youtube Trend® Mortise & Tenon Jig - Google Search

Trend Mortise & Tenon Jig - YouTube

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## MAFoElffen (Jun 8, 2012)

<<Any ideas?>>
Adjustable angle jig, RAS aux shaft with a slot mortising bit.


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## darsev (Feb 3, 2012)

Thanks everyone for your responses. I would have replied earlier except I spent most of the day pulling apart a room divider (silky oak) for sanding and repair. Sadly the silky oak will be painted over - too much damage where the repairs have used other than silky oak.

I have put together a couple of the ideas suggested from Charles and Neville, and attached is a plan of what I will do. The plan is a simplified view of the table I am building to give some context. Neville, I won't be putting in a rail around the legs at the top, and I suspect that I have the legs at 90 degrees to the way you were imagining them. I had thought about cutting the tenon on the leg at 15 degrees, but I only have 19mm to play with in this direction, and I didn't think it would be thick enough. Hopefully the plan will make this a bit clearer, but also note that this is a concept plan and details have deliberately left out e.g. the bottom rail for the magazine rack is shown only in one elevation and is missing in the other views.

What I have decided to do is to make the mortise about 3 times wider than the leg i.e. 60mm wide instead of 19mm, and cut it the normal 90 degree angle. Then I will cut a filler block and split it in two at a 15 degree angle, giving two blocks approx 20mm each. Screw the filler blocks into the mortise leaving a gap in the middle for the 19mm rail which will be at 15 degrees. The drawing should make this clearer in the detail component. The red are the filler blocks.

Again, thanks for everyone's assistance - it was your ideas that helped me figure it out. I will put some photos up later when the table is done. That should be soon as someone is coming tomorrow to select the slab to use. 

Darryl


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## Bradleytavares (Feb 25, 2012)

Bravo! Innovation at it's best. And I was ready to offer the Festool domino as a thought.


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## darsev (Feb 3, 2012)

Hi everyone. It's been longer than I wanted to post back, but I cut into my thumb on the table saw. The doctors got involved and now I am effectively grounded. I will get the job done asap, and when it does I will post the photos. I was "supervising" the construction of some stage boxes this morning, and I am feeling a bit sore in my thumb even though I didn't really do anything.... For the record, I haven't cut anything completely off, it was just a pretty deep cut that will take more than a few days to get right.

The people who want the table understand and are probably more patient than I am. I am getting itchy feet waiting to get back to the jobs in my workshop, but I want you all to know I haven't forgotten you and your help. I just haven't been able to put it into practice. 

Thanks, 
Darryl


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## darsev (Feb 3, 2012)

Hi everyone,
Finally back in the workshop but not quite at full speed yet. I have, however, managed to cut the 15° mortises and get a dry fit of the legs. Photos attached. As discussed in previous posts, I used a filler block that was split at 15°. One big advantage to this was settIng the angle on the saw once and splitting the filler blocks, and cutting bevels into the legs all at the same time. Even if the angle wasn't exact, it was consistent for everything, so it didn't really matter.

The first photo shows the mortise cut and the leg and filler blocks behind. The second shows one filler block and the leg in position. The third shows the second filler block in position, but not driven home. The mortise was cut slightly under size, and the filler block planed until it was a tight fit, The last photo shows all three legs in a dry fit. I'll put in a magazine rack at the bottom of the legs, and that will provide enough bracing that nothing will move the legs short of destroying it.

Once again, thanks to everyone for their suggestions. Hopefully I will have this table finished this week.

Darnyl.


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