Turning a Timber into a Mast

Yesterday I bailed out after a short time outside in the hot sun.  If I keep doing that, I won't get much done until October, and then I'll be wanting to take camping and bike trips and sail.  So today I resolved to press on, hot or not, and made good progress.


The mast timber was already cut and planed to the right thickness and taper, but was still 4-sided.

Today I finished marking the cut lines to make it 8-sided, using my magic spar gauge. Using the circular saw set at 45 degrees, I cut off the 4 corners, leaving about 3/16" margin to finish with the plane. The picture is fuzzy because when I took the camera outside the temperature difference made the lens fog up immediately.

That gave me an 8-sided spar.  In this photograph, foreshortening makes it look like the spar comes to a point.  The actual taper is from a max of 3 1/4" down to 1 1/4" at the head. For the next step, making it 16-sided, I'd intended to do the job by eye, using the plane alone.  But the 8 siding had gone well, and I trusted my graphic skill more than my eye, so I carefully measured and marked lines to plane to.  It turns out that each face of a 16 sided polygon is .209 times the diamater.  A lot of measuring and marking, but it just took patience..At the thin end, small errors in marking made for unequal 16 sides, so for the last three feet I did do the job by eye.

After planing to the marks, here is the result, a tapered 16-sided spar.

Then I buzzed off each of the 16 edges with the plane set on its minimum depth.  It's ready to sand and finish, but that's for another day.

There are a couple of knots in the mast which worry me. Trimming the timber down didn't eliminate them.  Before I finish the spar I'll fill the gaps with epoxy and reinforce the spots with small patches of fiberglass cloth.  I hope that makes the mast strong enough. If it fails, I know how to make another.