By Ronn Hann of Northern Comfort Log Homes
Reprinted from Fall 2006 newsletter
The notching system I use has best been described as “scribing onto the scarfs.” Follow me through. The scarfs are layed out and cut at the same time as the rough notches and are scribed onto for the final scribe. To layout scarfs, I use a scarf saddle board. I made it from several scraps of 1/8” thick pine boards, 6” wide and fastened the two scarf shaped cutouts with 1-1/2” pieces of inner tube and staples. I bandsaw cut these out about 12” longer than the biggest diameter log I use on the project. The two pieces hang over the log with about a 4” gap between them.
When cutting the scarfs, try to maintain at least a 4” width on top of the notch. This makes scribing easier because you don’t dip down on the scarf when scribing. This makes notching easier also because you can plunge cut out the bottom of the notch. Mini-pro bars are made 2-1/2” wide and do that job nicely.
Back to scribing the rough notches. For this job, I decided to use my tape measure body of approximately 1-1/2” thick as a scriber gapsetting tool. In use, the tape is laid on its side under the log to be rough notched inside near the notch. The scribers are opened up to the difference and you start your rough scribe lines.
The tape is then laid on the log being scribed to and a short horizontal line with a V shaped pen mark (a cheveron) indicates the limit for the scarf cut. This also indicates waste material that can be cut out with the rough notch and for scriber relief. A requirement for a finish “scribed onto scarf.”
After scribing all the rough notches to within 1-1/2” of the log below, I take the logs down from the wall and cut the scarfs first. With the Cheveron in sight, this indicates the bottom edge of the scarf. When you sight the V shaped line, you easily can make that part of the log the horizon and with the saw cut accurately to the bottom edge of the scarf. On deeper scarfs, I often stop half way to check my cut. If not on or near my layout line, I restart the scarf cut. Time is saved by not cutting twice to achieve what 1or 1-1/2 cuts will do. The step cut in the off cut of the scarf saddle shows that you at least looked at the line. Plane and sand to finish scarf.
If a lock notch or square notch is required for the log, I just stand the tape up and this will leave about 3-1/2” for a final scribe and enough wood for a lock.
With the logs I use the 1-1/2” left inside the notch after rough notching usually means a final scriber setting of 2 – 2-1/2”. The taper in the logs then is what does the math of wall building and adjustments for log height is done by log selection rather than using scriber math. On some notch logs, this 1-1/2” gap means the log cradles are replaced by a 1-1/2” block near the door or window opening before final scribing.
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