butteressing log construction for a WWI German mortar pit . how are the logs connected?

[Steven]

Hello all
I am building a german heavy mortar pit for the WWI GB Here I am building something akin to the construction shown in the pic
My question is this, judging from the pic how would you say that the circled interlocking logs are fastened to one another. One of the circled interlocking crossbeams seem to be secured with a metal band
the other two (cirkeled ) seem to be secured with (supposedly fairly large ) nails ...- given the sizeable beams and the nature of the construction I would expect heavy bolts going through secured with nuts.
I want to keep the build representative of methods used - rather than just gluing logs togheter.

[spanner570]

Steven.
The long ones on the right are 'Half Lapped', nailed and then banded with steel hoops. The hoops would also be nailed.

If you take a look at the construction at the lower level just above the mortar. There are a couple of small straps on the right, but for the most part they will all be nailed.

Note also the long beams all have notches in them to take the ends of the smaller diagonal braces. I doubt very much if bolts would be used. Happy to be proved wrong mind......:upside:

Ron

[stillp]

There seem to be metal straps holding the diagonal brace at the bottom of the RH vertical log too.
I would have expected them to be held together with trenails, tapered wooden pegs, but they do look like standard metal nails.

Pete

[Guest]

When was that photo taken? IOW: is that a genuine picture from the war, or from some reenactment or museum piece in a replica gun pit?

[Steven]

When was that photo taken? IOW: is that a genuine picture from the war, or from some reenactment or museum piece in a replica gun pit?

the pic is from the IWM database: https://www.iwm.org.uk/collections/i...ject/205132717 depicting a british trench mortar training facility in 1917. Let med hasten to add that I am not c/p a british design onto a german I am merely interested in the method of joining the logs as the method was used by the germans in construction of field fortifications

[Steven]

Steven.
The long ones on the right are 'Half Lapped', nailed and then banded with steel hoops. The hoops would also be nailed.

If you take a look at the construction at the lower level just above the mortar. There are a couple of small straps on the right, but for the most part they will all be nailed.

Note also the long beams all have notches in them to take the ends of the smaller diagonal braces. I doubt very much if bolts would be used. Happy to be proved wrong mind......:upside:

Ron

Very concise and very useful info - thanks a lot:thumb2:

out of pure interest, a follow - up question:

would the bands be heated and put on the logs and cooled down and contracting for added strength?

[Guest]

the pic is from the IWM database: https://www.iwm.org.uk/collections/i...ject/205132717 depicting a british trench mortar training facility in 1917. Let med hasten to add that I am not c/p a british design onto a german I am merely interested in the method of joining the logs as the method was used by the germans in construction of field fortifications

The reason I asked was because I really couldn’t tell from the photo, and so I was wondering if you weren’t accidentally trying to replicate some re-enactor’s or museum staff’s best guess/bodge job. But happily, it seems you aren’t

[spanner570]

would the bands be heated and put on the logs and cooled down and contracting for added strength?

No, they would be put on cold, but tight. Then nailed. The damp etc. would probably tighten the timbers even more. If the bands were heated first you would probably be able to detect slight scorch marks.
Bottom picture above the right hand soldier, you can see a large iron staple. These were usually driven in at the joint with a large hammer. They were slightly tapered which meant when they were driven into the log joint they actually pulled the logs together thus tightened the joint. Then the straps would be tied around and nailed.

You can see a redundant staple hammered into a log in the top picture just above the door sign.

Cheers.
Ron

[Steven]

Thanks Ron
Joint half - lapped, staples and steel bands (pie tin foil) are primed and will be added when ready

[BigGreg]

very nice build... can't wait to see more

[Steven]

Thanks Gregory pretty much done - I'll post some pics in the completed section, you can follow the build here