2017.03.21 - Square to Octagonal
I had planned to put the fourth coat of varnish on the boat this evening but it was such a nice day when I started that I decided to work on the boom first.
The first thing to do was to run the belt sander over each face of the boom to remove the excess epoxy and to leave a flat surface that will run over the table saw without getting stuck on any bits sticking out. You can see that the end is slightly damaged and splitting but this is not important as the corners are to be cut off and that will also cut off the split section.
The table saw was carefully set up with the four rollers two in the in-feed side and two on the out-feed. These had to be set up to be all at the same level as the table itself. The fence was set on the table and a baulk of timber clamped to the table on the other side so that the boom is guided down a channel over the saw blade. The setting up took about an hour to accomplish. Here you can see the boom halfway through the first cut. The table saw is only small and trying to make the cut all at once would probably cause the thermal cutout to trip so I rested the saw by leaving it running so that air is drawn through the motor to cool it. The boom was also pushed back a little so that the blade was not cutting anything. Doing this at intervals prevented the motor from overheating.
Still the first cut but from the outside. You can just see the cut off corner.
The first cut completed. It took about 5 minutes to make each cut and the rollers made it easy to feed the boom through the saw. No strain on my back at all.
The second cut.
And the third cut.
And finally the fourth cut.
Having put away the table saw and rollers I put the boom on two saw horses for support and ran the planer over each freshly cut face. I deliberately made the cuts just a little too shallow so that planing the saw marks out of the faces would bring the faces to the correct depth.
I'm always tempted to leave the spars octagonal when I do this, they look so good.
I did make a small error at the start but once the corners have been cut off a second time the error will probably not be noticeable. Besides which, the boom is around a foot too long to allow for errors and even if it were not, the outboard end of the boom, the one farthest away from the mast will be tapered over the last six inches or so and that would certainly remove the error.
Once all this had been completed the fourth coat of varnish was applied to the boat, so it was a long stint this evening.