Joint Practice

[SteveMP]

Here are your next challenges, Al.View attachment 58492

View attachment 58493

Pretty interesting joinery. Its funny, a few years back, traveling to Germany for work, i stopped in Heidelberg on my way to Munich. I went to this old pub in Heidelberg (i think from 1700s?) . Everyone else in there is enjoying the food and beer and I am sitting there admiring all the old joinery. Especially the timber framing and how some of the cross beams were cut to fit. Just a couple of the probably 50 pics i snapped in there

 

[Cabinetman]

Yes I can see exactly what attracted you to it, I’m a bit the same, this is from a pub in Dunmow High Roding in Essex, dates way way back. I have another pic showing very old designs painted onto the uprights too.
Your pics are much more atmospheric than mine though!

 

[Dr.Al]

Here are your next challenges, Al.View attachment 58492

View attachment 58493

Eeep! I think that might be a bit beyond me!

 

[Dr.Al]

Yesterday's effort, planed and (because it's Ash) card scraped clean this afternoon - a dovetailed bridle joint:



For anyone who hasn't seen it before & wants to try to figure out/guess how it goes together, I'll wait until tomorrow before sharing the internal details.

If you know how it works, please keep it to yourself so others can think about it.

Views from multiple sides:

 

[SteveMP]

Yesterday's effort, planed and (because it's Ash) card scraped clean this afternoon - a dovetailed bridle joint:

View attachment 58532

For anyone who hasn't seen it before & wants to try to figure out/guess how it goes together, I'll wait until tomorrow before sharing the internal details.

If you know how it works, please keep it to yourself so others can think about it.

Views from multiple sides:

I have an idea, but will wait

 

[Dr.Al]

I promised an explanation so here it is.

It's a very silly (and weak) joint with no practical application. I'll take it into work along with the other two & see whether any of the mechanical engineers can figure them out

The two parts look like this, so it isn't really a bridle joint:





It relies on the wood being moderately bendable, so the little bridge gets steamed or, in my case, has a kettleful of boiling water poured over it. That allows it to be assembled like this:



The glue on the little hidden wings of the dovetail provides the only strength to the joint.

Pointless, but a fun exercise & good practice at cutting without breaking a fragile part. It'll also be fun to watch the clankies (mechanical engineers) squirm as they try to get their head round it!

 

[AndyT]

Neatly done.

Have you also explored the various metal puzzle equivalents, like the two headed bolt with a loose nut in the middle?

 

[Dr.Al]

Neatly done.

Thanks

Have you also explored the various metal puzzle equivalents, like the two headed bolt with a loose nut in the middle?

I've already got one of those on my desk (made mainly as a way of practising cutting multi-start threads):

 

[AndyT]

That's it!

Very good.

 

[SteveMP]

I promised an explanation so here it is.

It's a very silly (and weak) joint with no practical application. I'll take it into work along with the other two & see whether any of the mechanical engineers can figure them out

The two parts look like this, so it isn't really a bridle joint:

View attachment 58614

View attachment 58615

It relies on the wood being moderately bendable, so the little bridge gets steamed or, in my case, has a kettleful of boiling water poured over it. That allows it to be assembled like this:

View attachment 58616

The glue on the little hidden wings of the dovetail provides the only strength to the joint.

Pointless, but a fun exercise & good practice at cutting without breaking a fragile part. It'll also be fun to watch the clankies (mechanical engineers) squirm as they try to get their head round it!

Interesting! Never would have guessed that. My guess was that the dovetails were cut super thin near the base and slowly tapered out to to full width at the end. And the thinness at the base allowed you to bend out the tails and then press back down.

Although obviously this one is a novelty, slightly similar joint the dovetailed lap joint can be super strong and provide ridgity when used correctly

 

[SteveMP]

Thanks

I've already got one of those on my desk (made mainly as a way of practising cutting multi-start threads):

View attachment 58617

There used to be a novelty shop at the mall that had a bunch of puzzles. We would go and sit there for hours in high school trying to figure them out. I can’t even remember them all. Except the one that is 2 horseshoes chained together, and there is a metal ring between them that is too small to go over the horseshoe but if you position everything correctly you can get the ring off. I am guessing on this though you cannot remove the nut?

 

[Dr.Al]

There used to be a novelty shop at the mall that had a bunch of puzzles. We would go and sit there for hours in high school trying to figure them out. I can’t even remember them all. Except the one that is 2 horseshoes chained together, and there is a metal ring between them that is too small to go over the horseshoe but if you position everything correctly you can get the ring off. I am guessing on this though you cannot remove the nut?

It's possible to remove it (otherwise it would be impossible to make). It's basically two screws fixed together end-to-end. The transition between the two screws happens part-way along the thread & is almost invisible.

To make it, you start with two bits of steel (stainless in this case) make some way of joining them together (a tapped hole in each & some threaded rod in this case) & very carefully face the end that will be joined so that it's extremely flat (the flatter they are the less chance of a visible join).

When the two pieces are then screwed together the two flat faces join with an almost invisible seam. You can then turn them as if they're a single piece, including cutting the thread. Finally, the parts are separated, the nut screwed onto one of them & then the parts rejoined tightly together.

 

[Dr.Al]

Enough puzzle joints for now. I thought I'd try something different: this one's called a Koshikake Kama Tsugi or Lapped Gooseneck Joint.

I made it a bit too tight: it went together with some persuasion on the trial fit but there was no way it was coming apart for glue application so I just planed it smooth. There are some small gaps, but not bad for a first attempt I think.

 

[SteveMP]

Enough puzzle joints for now. I thought I'd try something different: this one's called a Koshikake Kama Tsugi or Lapped Gooseneck Joint.

I made it a bit too tight: it went together with some persuasion on the trial fit but there was no way it was coming apart for glue application so I just planed it smooth. There are some small gaps, but not bad for a first attempt I think.

View attachment 58644

View attachment 58645


View attachment 58646

This joint I have seen a lot of in various videos on japanese joinery. Looks great. I still need to learn how to mark this stuff. I know there are formulas the builders use like 1/3 of width or length etc. But I am the type of person that like to follow a plan.

 

[Dr.Al]

This joint I have seen a lot of in various videos on japanese joinery. Looks great. I still need to learn how to mark this stuff. I know there are formulas the builders use like 1/3 of width or length etc. But I am the type of person that like to follow a plan.

That one's in "The Complete Japanese Joinery" by Hideo Sato & Yasua Nakahara (with suggestions on proportions and step-by-step cutting instructions) & also in Dorian Bracht's book (with suggested proportions only) so that was all quite helpful for me. I followed the steps in the Sato book when I cut the joint, although I did more chisel paring rather than sawing to the line every time - on something this small (40 mm square) the paring is quite quick.

 

[Dr.Al]

It's probably worth mentioning that I did all the marking from face side & edge rather than centreline. I think centreline is normal for big stuff as it may not have completely clean faces, but my little 40 mm square blanks were all planed square in advance of this exercise & trying to work off a centreline on something this small felt quite a challenge to me.

 

[SteveMP]

That one's in "The Complete Japanese Joinery" by Hideo Sato & Yasua Nakahara (with suggestions on proportions and step-by-step cutting instructions) & also in Dorian Bracht's book (with suggested proportions only) so that was all quite helpful for me. I followed the steps in the Sato book when I cut the joint, although I did more chisel paring rather than sawing to the line every time - on something this small (40 mm square) the paring is quite quick.

Ah yes, have been looking for that book for years, but out of my price range.