Designing some side tables, out of comfort zone, input need please!

[Rorton]

Wasn’t sure to be honest Pete. Does the material from the tenon not need to completely fill the mortise. didn’t think gaps top and bottom would be acceptable?

 

[Trainee neophyte]

I mentioned the other day that I am failing on mortices at the moment. I keep making projects with 40 mortice and tenon joints, which is a lot to attempt with a chisel. Perhaps I should have done though, as it might have been more accurate. The router did a less than perfect job.

Things I have failed at, in no particular order:

Marking out. Stupid, I know, but if you don't put the marks in the right place, how can you cut accurately? Get a mortice gauge, or a marking knife, or both. Pencil lines just don't cut it (pun fully intended).​

Controlling a router: the beast has has a life of its own and leaps around like a thing possessed. Jigs, clamps, fences etc to corral the monster are a must. Using a router table ought to help, but cutting to the (innacurate pencil) line and not past it is apparently beyond my ability. Stop blocks would help, but my workpiece was 2 metres long with 10 mortices spread along it, and the table considerably shorter than that. Need to find a solution for that. Also I must make some feather boards urgently. It's all about repeatability. Some of my mortices weren't just too long, but "J" shaped. ​

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Chiselling to the middle, but no further: YouTube is full of mortices with crisp, clean edges and no tear-out from going too far. My mortices don't look like that if cut by hand. Work to the middle from either side is eminently sensible, but cleaning up the last finishing touches it is just too easy to go too far and fall out of the other side, taking a big, ugly lump out at the same time.I rush things - bull in a china shop. Slow down. Really slow. Really, really slow.​

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The above is an incomplete list of my failings compiled mostly for my benefit, but perhaps it may help someone else. They say "Measure twice, cut once", but it really ought to be "Think twice, cut once".

​

 

[Cabinetman]

I feel your pain and frustration, and I hope you can feel how cold damp and locked down we all are here back in Blighty! Sorry that doesn’t help really with the mortise and tenons,
Do you have a pillar drill? You could fit a fence to run your wood against and drill most of it out, I certainly wouldn’t attempt to cut mortises with a router – they do tend to have a mind of their own haha. Random thought, how about putting the router cutter in the pillar drill, never tried it so please don’t blame me. Ian

 

[billw]

They say "Measure twice, cut once", but it really ought to be "Think twice, cut once"

Think
Measure
Think again
Measure again
Mark it up
Think about whether it looks right
Go for coffee
Come back with fresh eyes and realise you did it wrong
Think again
Measure again
Mark again
Cut
Wait five minutes
Realise you cut it wrong

 

[spb]

Think
Measure
Think again
Measure again
Mark it up
Think about whether it looks right
Go for coffee
Come back with fresh eyes and realise you did it wrong
Think again
Measure again
Mark again
Cut
Wait five minutes
Realise you cut it wrong

Replace that last line with "realise you marked it right the first time and shouldn't have changed it". Far more infuriating that way.

 

[Trainee neophyte]

I feel your pain and frustration, and I hope you can feel how cold damp and locked down we all are here back in Blighty! Sorry that doesn’t help really with the mortise and tenons,
Do you have a pillar drill? You could fit a fence to run your wood against and drill most of it out, I certainly wouldn’t attempt to cut mortises with a router – they do tend to have a mind of their own haha. Random thought, how about putting the router cutter in the pillar drill, never tried it so please don’t blame me. Ian

I have a "pillar drill" made of finest chinesium - one of Lidl ' s more interesting offerings. It is my intention to get better at this, so I think the next 40 mortise project will be hand tools only - the last mortise I cut ought to be better than the first, you would think. Also, I should stop using cheapest wide grain soft pine. The search for the perfect mortise continues...

 

[Racers]

Wasn’t sure to be honest Pete. Does the material from the tenon not need to completely fill the mortise. didn’t think gaps top and bottom would be acceptable?

End grain gluing dosn't have any strength, its just the long grain of the sides that give the strength, so the ends don't have to be square or even fit, you have to watch the allignment when assembling but thats about the only drawback.
Its easer to wiggle out when test fitting as well.

Pete

 

[Rorton]

thanks Pete, it was more the top and bottom that I was concerned about. If I did this with the router, and made a slot with an arched top and bottom, the square tenon would only touch at the sides (green highlight) and the back if I get the length correct - but the 2 bits highlighted in red would have no material in them - I was assuming that it would be then prone to racking as the apron would have nothing solid to bear against - maybe not as important in a small side table - my train of thought was that a good mechanical joint, which is then secured with glue.

 

[Sheffield Tony]

Thanks , as above, 5mm all round for a shoulder, with 15mm at the top to leave some meat in the top of the leg - would that be OK - and then a 15mm protrusion

Ive moved the legs in from the edge of where the bevel starts 5mm also

View attachment 96903

I am surprised nobody has yet mentioned that this ought to be a haunched M&T.

My only other suggestion is that I'd not be drawn by the advice to drill out some of the waste. Unless it is a pretty big mortice and a brace and bit might be appropriate. Just get a proper mortice chisel, a big mallet and set to it. The correct mortice size is the width of the chisel you have, set the gauge to it and saw the tenon to suit. Remember to start near the middle of the mortice, only approaching the ends with light paring cuts to get a nice clean, accurately placed end without rounding over from levering. I find drilling it out strangely harder to produce a clean result, and knocking a square chisel into a series of round holes gives increased chance of spiltting the top of the leg.

 

[Sheffield Tony]

Sorry, didn't spot your last post - if you are going to use the router, why not saw the tenon a bit wider and round the ends to fit the hole ?

 

[Rorton]

thanks for both replies, had to lookup haunched M&T! so if I had a 1/4 Mortice chisel, that is enough based on the 20mm thickness of the apron, I shouldn't be aiming for double that width?

I could round the ends of the tenon I guess, hence my question about squaring out the hole left by a router if I went that route - I guess it doesnt matter if you square the router hole, or round the tenon to suit the routed hole?

 

[spb]

thanks for both replies, had to lookup haunched M&T! so if I had a 1/4 Mortice chisel, that is enough based on the 20mm thickness of the apron, I shouldn't be aiming for double that width?

Generally you want to be choosing your mortice chisel based on the thickness of the piece being morticed, so in this case the leg. Look at the joint in cross section, and you've got three pieces glued together - the tenon, and the two sides of the mortice surrounding it. You want the thinnest of those three to be as thick as possible.

If your two pieces are the same thickness, that means making the mortice roughly 1/3 of it. When they're different, then look at where they need to join, how much you can offset the tenon towards the centre of the morticed piece, and how thick you can make it without compromising the walls.

Of course, this is all theoretical - if what you've got is a 1/4" chisel, and the joint isn't bearing huge loads, then just use that. It'll work fine.

 

[Cabinetman]

I am surprised nobody has yet mentioned that this ought to be a haunched M&T.

My only other suggestion is that I'd not be drawn by the advice to drill out some of the waste. Unless it is a pretty big mortice and a brace and bit might be appropriate. Just get a proper mortice chisel, a big mallet and set to it. The correct mortice size is the width of the chisel you have, set the gauge to it and saw the tenon to suit. Remember to start near the middle of the mortice, only approaching the ends with light paring cuts to get a nice clean, accurately placed end without rounding over from levering. I find drilling it out strangely harder to produce a clean result, and knocking a square chisel into a series of round holes gives increased chance of spiltting the top of the leg.

Not necessarily Tony, The haunch is usually there to cover up a groove that runs through the joint as in when fitting a panel, actually though in this case as the top of the joint is covered by the tabletop it’s possible to use an open-ended Mortice and Tenon in which case the mortice could be cut in all sorts of different ways. Ian

 

[Rorton]

another thought, if I was to make a smaller table that would nestle under this one, its going to be nearly half the width of the one im planning to make, so would I reduce everything to suit? Would the legs then need to be 20mm tapering to 10mm, aprons 10mm etc...

 

[Cabinetman]

Nice thought Rorton, but it doesn’t always just follow that way, its proportions and aesthetic’s, most of the time it’s just what looks right.

 

[Sheffield Tony]

Not necessarily Tony, The haunch is usually there to cover up a groove that runs through the joint as in when fitting a panel, actually though in this case as the top of the joint is covered by the tabletop it’s possible to use an open-ended Mortice and Tenon in which case the mortice could be cut in all sorts of different ways. Ian

I'm going to mildly disagree here. The purpose of the haunch is to allow you to put the mortice a bit further from the top of the leg, whilst maintaining glue area and keeping the joint in good alignment. If it were just to fill up the end of a groove (which it can often be usefully used to do) there would be no purpose for the diminished haunch M&T.

Going back to sizing of the mortice, I think the OP is in danger of over-thinking this. If you are cutting a traditional joint by hand, the width is the size of your chisel, the chisel size you pick is somewhere in the range which is strong enough, without making it really hard work. I would suggest anywhere from 1/4 to 1/2" will be fine for something this size in oak. If I had only space for one mortice chisel in my toolbox, I'd pick 5/16" (8mm ish) as the best compromise.

 

[Rorton]

Nice thought Rorton, but it doesn’t always just follow that way, its proportions and aesthetic’s, most of the time it’s just what looks right.

Cheers. I think I’ll get the 2 tables that are similar done (one slightly smaller top than the other due to space) and then think about if we need another one later

 

[Rorton]

OK wife would like the tabletop another 150mm higher, so have raised that, added an extra 10mm to the aprons which are now 70mm, and the top is also 50mm longer

Whole top is now 550mm x 355mm
Whole height of unit to the top of the table is 585mm

For reference, gap between the legs on the short side is 185mm, and 380 on the long side

Legs are still the same 40mm taper to 20 inside edges only

Still look in proportion, not to spindly? Aprons deep enough? The second will have the same height, but his top will be 460mm x 300mm

 

[Jameshow]

I'm going to mildly disagree here. The purpose of the haunch is to allow you to put the mortice a bit further from the top of the leg, whilst maintaining glue area and keeping the joint in good alignment. If it were just to fill up the end of a groove (which it can often be usefully used to do) there would be no purpose for the diminished haunch M&T.

Going back to sizing of the mortice, I think the OP is in danger of over-thinking this. If you are cutting a traditional joint by hand, the width is the size of your chisel, the chisel size you pick is somewhere in the range which is strong enough, without making it really hard work. I would suggest anywhere from 1/4 to 1/2" will be fine for something this size in oak. If I had only space for one mortice chisel in my toolbox, I'd pick 5/16" (8mm ish) as the best compromise.

Out of interest which manufacturers make odd sized chisels??

Cheers James

 

[jcassidy]

+1 for "it's all about the chisel you have". The thicker the mortice, the more work you've given yourself.

-1 for rounding the mortice, you will not have a tight joint and will be relying on glue for strength. Cut the mortice however you want, but either square the mortice or round the tenons. You can't have both!