Timber Framers Guild Forums General General Forum Questions cutting curves with a chainsaw

has anyone ever used an alaska chainsaw mill to cut curves in large( 14 x 20 x 20 foot)pieces.?
eg. the bottom chord of a ridiculously large deco-truss.

i figure we just use a 2x10 as the guide and bend it into the approximate arc, set the mill to the appropriate cut and away we go, creating a smooth cut requiring minimal clean-up.
any thoughts?
chris

I know that Jack Sobon has done something like this with a sperber mill (similiar to the alaska only with rollers). I believe the idea there was to start with a curved log with as close to the arc (or between the two arcs) wanted as possible, then bend a guide board as you indicated.

I assume you should be able to do this with your 14x20 but I haven't tried it and have always wondered curved you can get before the saw starts binding on the inside arc.

I believe that a carving bar is not as wide as a standard chain bar and might address issues with the chain saw binding on a tight curve. That said, if you are bending a 2x10 to form your guide I suspect you would be well within normal curve cutting radius. Nice twig sizes.

Hi all:

Try marking out the radius of your cut on both sides of the timber, then cut down to nearly the line about every 3 or 4 inches--knock the blocks away and then clean up the surface up with a carpenters adze, this is a very simple chore, and leaves a nice undulating surface on the timber.
I just finished the inside surface of a pressure box constructed with 10 by 12 oak timbers, and found that this worked quite well. The diameter of the circle was 36" and from this you can see that the circle was real tight as far as the arc goes.

Nothing seems to work as good on inside curved surfaces as a carpenters flat edged adze, even in this modern era I had to resort back to the original tools to do the job.

good luck
NH

It's fun working with curved stuff:



After my friend/student finished this he asked what should he work on next? Another student said: "I think you should make a "B" now!

Jim Rogers