Alan Peters step stool

[eoinsgaff]

I’ve started working on Alan Peters step stool and i’ve been frozen with a joinery conundrum. I may be over thinking this or I may be missing something blindingly obvious but here goes...

 

[eoinsgaff]

So this is the target...

 

[eoinsgaff]

 

[eoinsgaff]

 

[eoinsgaff]

Ok, at last the right way round,

The wedged tendons are a challenge as they are but they are compounded by the tapered ‘leg’.
Planing this taper will mean planing the taper into the tenons as well. The piece is never thick enough to allow the double tenons to be set back - even less so as I’m making a half sized piece.
Don’t ask...

 

[custard]

A very similar stool is still an apprentice piece at the Barnsley Workshop, where Alan Peters trained. Here's the one I made when I trained there,

It's a bit of a pig to make for all sorts of reasons that aren't immediately apparent until you actually get stuck in! The legs for example are set into shallow housings on the underside of the top, this is to ensure a really tight and clean joint line, but you'll need a paring block made at the correct angle to execute the angled housing. Another "gotcha" is the glue-up, if you want super clean glue lines be prepared for some involved cramping,

Regarding the wedged tenons, Barnsley make wedged tenons in a very particular way. I believe, but I'm not 100% sure, that Alan Peters used the exact same method throughout his career. Essentially you need to do two things, firstly you cut the kerf for the wedge into the tenon at an angle, so it's only about 1mm from breaking out at the edge. This means the edge of the tenon "folds" away with no risk of splitting as the wedge is inserted. The second thing is you chisel in a precise space for the wedge at the ends of the mortice, the wedges are also sized very precisely. The whole point is to get the two wedges the exact same thickness, having wedged through tenons where the wedges are different thicknesses would render the entire piece fit only for firewood, which is a bit disappointing when you've sunk north of a 100 hours getting the stool ready to have the wedges fitted!

 

[custard]

Here's another photo of the stool,

One other tip to help get the wedges identical, instead of just bashing one home then moving on to the other, use a sized block next to the wedge so both wedges can only get inserted by the same identical amount, and tap them home alternating from side to side.

Smashing project, good luck with it!

 

[AndyT]

I was struggling to see the problem but I have reread your post and Custard's and I think I get it now.
I think you do indeed plane a taper into the thickness of the ends, from both sides, so the tenons do end up tapered. But inserting the wedges brings them back up square to fit into square cut mortises, or even wedges them to slope the other way if the mortises are slightly flared. It will definitely need careful measuring and cutting.

It would also be possible to plane right through, then chisel wood away until the tenons were parallel (and thinner) if you preferred.

 

[custard]

The wedged tendons are a challenge as they are but they are compounded by the tapered ‘leg’.

I missed this bit.

I'll take a flyer here and say even though the leg is tapered the tenon isn't. In other words the leg taper is only over, say, the bottom three quarters, and tapers back into being a normal, parallel thickness board at the top where the tenons are. Either that or just the tenons themselves have the taper removed (chisel or shoulder plane).

This piece isn't designed to be simple, but at the same time life's too short for tapered tenons!

 

[custard]

Here's a sketch showing the key features of the Barnsley style wedged through tenon. Note the saw kerfs cut in the tenon to receive the wedges, and how they're angled and finish just about a mill from the edges. Note also the angled ends to the mortice (down to about 3mm from the bottom which remains parallel), these angled ends and the wedges are precisely sized so that they fit one into the other. The angles on this sketch are a little exaggerated to make the point.

 

[eoinsgaff]

Cheers Custard and Andy.

This is beginning to be an even bigger challenge.
I’ve made the stool half size as a trial run and to test a change in proportion- I want to see if making the stool longer/wider still allows it to look well.

Cutting the ‘dish’ out of the top adds a further issue for the tenons. My first thought was to cut, fit, wedge and glue them in place before making the ‘dish’ but this is likely to uncover poorly fitting tenons.

Alan Peters does recommend cutting out the mortises and filling with a softwood while planing out the ‘dish’.

There may be a clue in there...

 

[eoinsgaff]

That’s a nice looking stool Custard but the joinery makes the exercise very impressive.

It might be a bridge to far for me.

 

[AndyT]

Cheers Custard and Andy.

Cutting the ‘dish’ out of the top adds a further issue for the tenons. My first thought was to cut, fit, wedge and glue them in place before making the ‘dish’ but this is likely to uncover poorly fitting tenons.

Alan Peters does recommend cutting out the mortises and filling with a softwood while planing out the ‘dish’.

There may be a clue in there...

I don't want to downplay the difficulty but you could put a positive spin on it. Try this:

Once you have learnt to make wedged through tenons which fit really well, you can exploit your skills and start to work with curved surfaces which frighten lesser woodworkers. You win!

 

[custard]

There's another reason why you cut the mortices before dishing the top. You need to lay out the mortice positions on both the upper and lower surface of the stool's top, and work through from both sides. However, you can't complete the lay out with sufficient accuracy on a previously dished top. So it's mortices first, shaping second. Interestingly this also fits with the general cabinet making axiom of "joint first, shape second", so it would be the default reaction of any experienced maker.

You'll get used to making and fitting softwood plugs, they're very common with top-end cabinet making. For example if you're gluing up in stages you often fit soft wood plugs in mortices to prevent them being crushed by cramp pressure.

 

[Just4Fun]

How would the plugs in the top be oriented?
If their grain ran vertically I can imagine that cutting across their end grain would make it harder to do the shaping, so would the grain of the plugs be aligned with the grain of the top?

How do you shape something like that anyway? My projects very rarely have anything except straight lines and flat surfaces and I wouldn't know where to start with a sculpted item like that.

 

[thetyreman]

the plans are from pg 160 -161 of alan peters book 'cabinet making the professional approach'

 

[woodbloke66]

I did one of these some years ago as well, based on the drawing in his book. Nothing too tricky, but the interesting part was using a customised convex soled jack plane to make the dished seat.

End view

and the top

Finished with a few coats of Osmo as I recollect - Rob

 

[eoinsgaff]

Much delayed update - I glued up the half size prototype only last night. A slow burner this one.

 

[custard]

Good for you for sticking with it.

 

[eoinsgaff]