Thread: Show me a better Joint

Cliff,

I think he means something like this. It would be similar to a beadlock joint, I suppose.

Rocker

Roddy, I'm trying to make sense of what you are saying. Can I paraphrase you by saying that the long grain/end grain thing is important but not the full story. After the glue begins to age the effectiveness of the long-grain gluing advantage is diminished, making the mechanical properties of the joint equally important. As the furniture piece ages still further, the mechanical properties begin to overwhelm the long-grain glue advantage. It seems to me (naively) that the mechanical advantage lies with your joint - and thus a case can be made that your joint is more sound if you consider the whole lifespan of an 'hierloom piece'.

A further thought is that the glue effectiveness diminishes rapidly as joint movement increases. Therefore, the joint which is mechanically superior at resisting torsional forces will be superior in the long term.

Interesting. Your are right about one thing. You have made me think.
Arron

It is a simple joint,all you need is somekind of device to hold the timber to the drill press while the dowels are being cut in the endgrain.

Roddy

Arron,

I can see that what you are saying about the mechanical advantage of Roddy's joint might be true in theory. But I cannot see it working out in practice because of the difficulty of forming the tenons accurately with a hole-saw, and then drilling the matching holes accurately enough to form a tight joint.

With regular M&T joints it is very easy, with suitable jigs, to cut the joints so as to achieve a snug fit, with perhaps 0.1 mm difference in size between the tenon and the mortice. I am very doubtful whether it would be feasible to achieve anything like as accurate a fit with Roddy's joint, unless perhaps you had a micro-adjustable 2-way cross-slide vice with some sort of accurate measuring device attached. Even then, it would be a very fiddly process.

Doubtless Roddy's joint could be made accurately with specialised computer-controlled drilling machinery, but I cannot see it being of much use to the ordinary woodworker.

Rocker

Originally Posted by roddy97

It is a simple joint,all you need is somekind of device to hold the timber to the drill press while the dowels are being cut in the endgrain.

Roddy

Roddy,

They are not dowels; they are round tenons. I would have thought, after 45 years, you would know the difference.

Rocker

OK Rocker you conceed that the joint is not as bad as you first thought,so now your going to make me look stupid He He He.



Roddy

Hi there,
I've been enthralled with this thing from the start, so went to work this morning and had a go at Roddy's controversial joint. Had a couple of goes in fact, on the first stuff I could lay my hands on. First it was some cypress, then some meranti...neither being real suitable. The best sharpest hole saw I had was a 3/4" Starret deep cutting one, so your original specs weren't followed, ditto the number of round tenons, only fitting 2 in the size timber I had. First go (using a close-sized spade bit) showed potential, so I made a spade bit to the right size then went again. The joint works fine at this simple level, firm, well seated and aligned.
A couple of things, which have been covered in earlier posts:
1/ Its no good trying to align 4 tenons with a holesaw in a handheld drill, although 2 came out ok. Use a jig on the drill press, or a horizontal borer.
2/ The slowest part of the process is chiselling around & between the tenons, a normal type being faster.
3/ The drilling of the mortices is faster, and easily aligned. No chiselling...
I think it has potential, but I'm not going to enter into the strength debate! I don't know enough about long and end grain proportions, but only to say that I thought the shoulder of any tenon had its part to play in resisting racking forces. Fence sitting?! Probably...

Originally Posted by roddy97

OK Rocker you conceed that the joint is not as bad as you first thought,so now your going to make me look stupid He He He.
Roddy

No need, your doing fine all by yourself

Roddy,

My original view on your joint was formed because of your misleading description of what it was. In particular, you described it as a dowel joint. After a great deal of confusion arising from this inaccurate description, it finally emerged that you meant a round-tenon joint, as was pointed out to you. But you continue to describe it as a dowel joint

I certainly concede that your joint is not as bad as I first thought. But nevertheless it seems to me to be much more difficult to make accurately than a regular mortice and tenon joint; and, as SilentC and others have argued, and I agree, the joint is weaker than a regular M&T joint. It also seems to me to be much more difficult to make accurately than a regular mortice and tenon joint. Making your joint would involve changing the normal configuration of a drill-press and fitting a vice to it. So I cannot see why the average woodworker would prefer your joint over a regular mortice and tenon.

Rocker

You cut the dowels on the drill press,cut the shoulders on the table saw,just like conventional tenons,and the bits between the dowel/tenon just fall out"Try it".

The slowest part of the process is chiselling around & between the tenons, a normal type being faster.

An intriguing [dare i say challenging] thread.

Roddy97 are you saying that you cut the shoulders in the same line as the kerf of the hole saw, so you don't have to chisle round the tenons, but just cut the waste away from the end of the rail? The waste already having been separated from the tenons by the hole saw. Still sounds fiddly, I can't see how the waste would

just fall out

Originally Posted by roddy97

It is a simple joint,all you need is somekind of device to hold the timber to the drill press while the dowels are being cut in the endgrain.

There you go again talking about dowels in the end grain (and hole saws) when you really mean use a tenon cutter to cut 4 round tenons 15mm in diameter. Spaced correctly, the wings on the tenon cutter will remove the waste from between each tenon and the rest of the waste could be removed using a table saw.

So what you're describing is a M&T joint with 4 round tenons and 4 round mortices.

the challenge will be aligning and spacing the 4 tenons and the 4 corresponding mortices so the resulting joint is not twisted.

Originally Posted by roddy97

Timber 100mmx20mm ,connecting to timber 70mmx50mm.

Drill with a hole saw,4@x15mm dowels evenly spaced,into the end of the piece,100x20,cut the shoulders on the panel saw,marry the dowels to the stile 70x50,mark and drill your 15mm holes,glue,best joint in the world.

Roddy

Roddy my simple Questions from your first post
What do you mean by 4@x15 mm
Do you mean 4 holes 15mm diam
What do you mean evenly spaced ?? ie in a line or a circle
As you are drilling only 15mm holes why a hole saw and what do you mean " hole saw " why not a forstner bit ( which can be more accurate than a hole saw depending on the set ) or brad point drill
Are the Dowels grooved or flat sided
Does the strength improve if the holes are flat bottom , and the dowels are also flat bottomed
Does the depth of cut , ie the clearence at the bottom of the hole effect the joint strength




Thought for the day

About 100 people choke to death on ballpoint pens each year.

Originally Posted by Ashore

What does Roddy mean by 4@x15 mm
As you are drilling only 15mm holes why a hole saw and what do you mean " hole saw " why not a forstner bit ( which can be more accurate than a hole saw depending on the set ) or brad point drill

Ashore
I think Roddy is refering to using one of these ...

Roddy my simple Questions from your first post

Have a look at some of the posts in between, especially the ones with pictures. We've covered your questions pretty well.

What holds dry joint members in place if there is no glue?