Birdsmouth on log rafters

[Debarker]

Hello.

Am building a small screen house from pine logs.  On the log beams that run along the top of the walls, I made cuts / chiseled to duplicate the edge of dimensional lumber.  The idea was to then cut birdsmouth in 2x6 rafters and then these rafters would sit in the cut out part of the log to duplicate stick built construction.  Now I am feeling more ambitious and am contemplating using logs instead of dimensional lumber for the rafters.  Does it makes sense to cut birdsmouth in the log rafters?  Is this ever done?  When researching online, it seems log rafters always just rest on top of beams both at top and bottom.  Thanks! 

[Don P]

Birdsmouth is commonly done. I cut 2 pattern rafters out of dimensional lumber and nail them on top of another piece of lumber to make a trough wide enough for the widest rafter, birdsmouth up. Put the log rafter in the trough, flattened upper edge down. Hold your mouth just right and follow the pattern with a chainsaw.

[Debarker]

Don P - very clever!  You probably saved me hours.  Thanks.

[Don P]

Another trick if you're new to doing relatively precise work with a chainsaw. When both arms are free you have pretty poor control. Lock your right, trigger arm, to your body as much as possible... imagine you are trying to clamp a book to your body under your arm. Brace the butt end of the saw into your body somewhere. When that is possible it usually improves control.