anyone recognise this type of joint? (circa 1967)

[Higon]

just came upon this... I had to look twice! The faces of this joint are 700mm wide.

 

[deema]

Looks like a Japanese framing joint. There is a video of a joint just like it on uTube, can't find the link to copy for you.

 

[Billy Flitch]

It looks like a imposable joint, if it is they usually slide together at a angle of about 45 degrees.

I just looked at the writing at the bottom of the picture and it says imposable joint, and don't you mean 70 m/m and not 700 m/m.

 

[Higon]

snip... don't you mean 70 m/m and not 700 m/m.

No Billy, it was 700mm (seven hundred) square, about 7m or 8m high with a huge gate hanging off it.

 

[Billy Flitch]

OK what ever you say, but when you look at it the flakey bits on the front of the joint they must be about 3" wide.

 

[GLFaria]

Couldn't you post any more pictures? I'm rather curious.

 

[Bod]

How was it done?
Enlarging the picture, shows the top of the dovetail, at right angles to the face, or even slightly down!

Bod

 

[wizard]

 

[Billy Flitch]

How was it done?
Enlarging the picture, shows the top of the dovetail, at right angles to the face, or even slightly down!

Bod

How its done is to trick your brain into seeing something it is in fact not seeing.

How that works is just the way I said it slides together at 45 degrees. If you take that dove tail to be the front of the joint ,on the right hand side of the post there is another dove tail and the chevron on the left hand side is also on the back of the joint, now these are not two dove tails or two chevrons but just one dove tail and one chevron cut at 45 degree angles so they slide together simple really.

Cut many different kinds when I was an apprentice good exercises in lay out and chisel work.

 

[SteveF]

=D> =D> =D>

 

[Brentingby]

Not right as it turns out

 

[Bod]

So the square hole, is for a locking key, and the slot further up has nothing to do with the joint.
I see it all now!!
Useful for splicing another bit in where there is limited headroom, but great weight has to be carried.

Bod

 

[deema]

http://youtu.be/Pm1oeNm7DEc

Found the link

 

[Billy Flitch]

Well found sir, interesting that the back dove tail is not in fact a dove tail but a open mortice and tenon, so it is a bridal joint. I`v learn t something new today good on you.

 

[Higon]

How was it done?
Enlarging the picture, shows the top of the dovetail, at right angles to the face, or even slightly down!

Bod

I 'think' its done differently than the apprentice piece mentioned elsewhere in this thread..(and the video method!) Here's a closer detail from the dovetail.. both sides (left / right) of the dovetail look the same depth. Also the small example in the video showed both a vertical and lateral moment required to engage it. Not impossible, even with a very large (several tons?) piece of timber, but why would you bother on a simple repair? Why the large bolt through the centre?

It does give me an idea about how it might have been done!

[EDIT] having watched the video again, I'm not so sure! lol

 

[Higon]

looking back at the first image, there appears to be a diagonal joint from just to the left of the 'peak'... looking something like this;

The reason for the large bolt would then be to clamp the pieces together. I can't recall if there was another higher up and I didn't photograph that area.

Certainly a lot easier to assemble when it's this big...

 

[Higon]

Couldn't you post any more pictures? I'm rather curious.

The only other shots I've come across are the back of the gate, somewhat cramped as it was open against the wall.

...and the front of the gate, although I couldn't get it all in one shot!

 

[Billy Flitch]

I meant to come back to this thread but life got in the way the imposable joint takes many forms even on the very page that Deema posted about you tube there is a post showing the imposable dove tail joint.
http://www.youtube.com/watch?v=oXVQyHp9l_o

I knocked this up to day just to show you the double dove tail is possible.

Just a bit of fun really.