Thank you S P for posting this. It is great to see this kind of a post on the forum.
42 years ago I inspected a historic horizontal log building near Frisco Colorado that had this kind of a corner notch. The only time I have ever seen this kind of a corner notch.
In a book- "Der Blockbau" published in Karlsruhe Germany, 1942, by Hermann Phleps a similar notch is shown on a historic log building in Karnten Province, Austria. In 1982 Lee Valley Tools Ltd. translated this book to English and published it under the title "The Craft of Log Building". On pager 64, figure 77/42 this notch is clearly illustrated. On page 67, figure 82 and 83, if you look close, you will see it again.
As to replicating the notch:
The historic photos above of the notches were on a historic hand hewn (broad axe) horizontal log building. The modern photos of the reproduced notch were on nominally dimensioned saw mill timbers.
You can use a template when building with sawn timbers. With hand hewn timbers you can not easily use a template because no two hewn timbers are alike do to the hewing process, the sweep, twist and taper of the log. The way to do it, as it was done historically, is to cut a notch on the top of all 4 corners of the last logs put into the walls. Then lay the the next 2 logs across at 90 deg. and taking into account the sweep, twist, and taper of all the logs, transfer the notch dimensions of the 4 new notches that you cut onto the bottom of the 2 new cross logs using a log scribe. Continue this process up to the top plate log.
This notch shown is an excellent notch (unnecessarily complicated in my opinion) because it not only locks the corner tight but it slopes out to drain any water from the corner notch.
brunoguastalla.net
