Thread: Stretcher Frame Joint

Graeme thanks for raising the issue, I Hope someone can help, I’m very interested in doing the same

I would say its a job for a tenoner first. Or with a bit more fiddling around a spindle moulder with a sliding table attachment and some head changing. Other wise jigs and sleds on the table saw may work but getting the mitred joints working when its taking two separate cuts is not ideal. The tenoner or spindle moulder can cut both top and bottom mitre in one pass.
And if its not done any of those ways then some laying out, cutting , chiseling and shooting on jigs with shoulder plane.

So I'd be doing it on my Tenoner if I was doing batches of them.
One of these machines.
https://www.youtube.com/watch?v=p4ybPlNwKpg
Rob

Thanks, Rob, I was hoping that you would come along.

I do not have, or have access to a tenoner - not the most common piece of workshop equipment.

The main difficulty that I see is in cutting the mortise, given:

• the square tenon must fit snuggly into that mortise, and
• the mitred edges must match.

Mitre - Stretcher Frame Joint 2.jpg

Something that would require two or even three passes on a spindle molder would really test my set up skills. Ditto (plus) on a saw table or router table.

The volume needed precludes chisels and shoulder planes. But stretcher frame bars are readily available at every art supply store, so someone has solved the problem.

One possible solution might be to cut the mortise first, then to use it as the reference to set up to cut the top and bottom mitres in one pass.

Another way possibly Graeme.
Accurately machine up strips. 4 types per frame section.
Two are taped together and cut on the ends as the top and bottom mitre. In one pass.
The other two are the tenon and shorter mortise strips. Cut both types in packs taped together on RAS or table saw probably.
The difference in configuration in gluing these together is how the two types of parts are made.

I'm always playing with different ways of doing things and every now and then I find something I never knew before . One recent find I like was for cleanly glueing stuff up with minimal excess running every where. Just two cottage cheese jars the pricey goats cheese and a cheap ( edit 1 or 1.5 inch ) black plastic bristled paint brush . I trim them to half length and they are stiff and apply glue perfectly neatly. They’re horrible for painting and good with tTtebond glue. The second jar is for water so first the exess can be washed off the joint corners with the same brush . And then the brush can be washed out.
Id be useing that sort of neat way of glueing the strips up. And also possibly putting a brad nail through each end of the glued up section to stop them sliding around. They can be pulled later or driven in to stay there.

Rob

Originally Posted by GraemeCook

The volume needed precludes chisels and shoulder planes. But stretcher frame bars are readily available at every art supply store, so someone has solved the problem.

The guy that solved it is paying someone to use his tenoner Id say.
Pretty sure the two part types needed require two or possibly three set ups on the tenoner. Just fence position and slot cutting height.
The slot cutting blade that cuts the mortice just has to be changed up or down for the second part with the fence set square. And the fence is adjusted to 45 degree when cutting tenons and mitres bits. I don't understand these things fully sometimes until I'm working my way through doing it.

That below is with the fence at an angle on some legs I was doing the other day.
Not exactly 45 degrees .
IMG_3745a.jpg

And that shows the second heads. Two of them. Behind the tenon cutting monsters. The scribe cutting square heads can be removed and a slot cutting blade fitted. Probably on the lower one. Just a 1/4 inch thick saw blade type thing . If the mortise and tenon is 1/4".
IMG_3746a.jpg

I just bought a second set of heads in UK off ebay for almost nothing for what they are . All nice full blades in them . They are banned over there I think .

A feathered mitre. All done on one machine (table saw.) Stacked cutting for mitres. Follow feed for sockets. Simple straight, parallel dressing for feather board.

Thanks Rob

I didn't know that you could put a slot cutting blade in a tenoner, and I still do not have one ...

Originally Posted by rustynail

A feathered mitre. All done on one machine (table saw.) Stacked cutting for mitres. Follow feed for sockets. Simple straight, parallel dressing for feather board.

Sounds interesting Rusty, but I am not sure that I follow you.

Could you break it down into simpler steps, please?

Graeme, Mitres are cut on ends with the pieces stacked one on top of the other. Say four pieces. One pass over the saw and the four pieces are mitred on one end. Reverse the four pieces and pass over the saw and all mitres are cut. Lower sawblade to suit half feather width, set fence to half thickness of material plus half saw kerf. Pass ends over saw with mitred end down on saw table to create socket.
The featheris just a straight piece of timber dressed to the required dimension to suit the sockets. Much like you see on mitred box corners.

Gotcha, RN, but I think we are talking about two different joints. If I have read you correctly, you are talking about what I would call a splined mitre joint or a loose spline mitre.

mitre - Loose Spline.jpg

I have also done quite a few frames with splined mitre joints and should have included them as a third option in my original post. These do work well, but lack the self alignment feature of the stretcher frame joint.

The joint I want to make has several names including Stretcher frame joint, mitred bridle joint, and double mitred bridle joint. Both sides are mitred for appearance, internally there is a square mortice and a matching tenon - these cause it ti self-align. In fact, it is common to assemble canvas frames without glue, and if the canvas later sags then wedges can be inserted into the joints forcing them apart and post tensioning the canvas. There are no loose splines.

Mitre - Stretcher Frame Joint.jpg

Queensland Art Gallery has a German made Stegherr machine for cutting stretcher bar joints in pairs.
Preserving our past - Australian Wood Review

Photo: AWR


I don't have one!

Found a video of the above Stegherr stretcher frame joint milling machine.
Stretcher Bar Milling Machine BRF - SHM Stegherr

Suspect it is out of my price range.

Looks like an affordable solution might be two passes on a spindle molder.

• First pass - cut the square mortice,
• Second pass - cut both mitres.

Accuracy of set-up between the passes will be absolutely crucial.