Thursday, February 11, 2010

Strips of fir

Spent yesterday evening ripping ten-foot lengths of fragrant fir, as cold blue dusk fell and the wind flung branches across the snow. The lights flickered a few times -- we lost power for two days in this last snowstorm -- so I clomped into the house, showering sawdust and snow, for my trusty small flashlight to loop around my neck under my clothes.

(Under my clothes because things hanging from one's neck are not conducive to retaining one's head when one is working around power tools.)

The power never went out, and I got a nice sore thumb from feeding the wood into the saw, as well as an even-nicer stack of bendy strips of fir I can scarf into stringers. Feel like some math? Come on, it'll be fun:

The Pathfinder plans use the metric system. I was skeptical at first but quickly converted when I realized that fractions would be a thing of the past. Hallelujah! What's 10 13/16 divided by three and don't forget to account for the saw kerf? Good grief.

The stringers are the longitudinal pieces running from bow to stern: one at the top (or sheer) where the edge of the deck is, one at the bottom (or chine) where the side planking meets the flat bottom, and two in between to give a healthy rounded shape to the hull. These are spec'd at 20x45 (millimeters). A 1-by is about 18mm thick, which in this case is close enough.

Trouble is, a 20x45 piece of wood -- about the size of a deck of cards viewed on end -- is not flexible enough to conform to the long and graceful curve that defines the sides of the boat. How do I know this? By breaking a piece that size.

Solution: glue the stringer from two smaller pieces, one above the other. That is: 20 x 22.5 and 20 x 22.5. Still with me?

Inconveniently, the boat is 17 feet long; the stringers -- because they arc out and then back in, need to be more like 18 feet. And it's hard to find lumber longer than 12 feet or so. Solution: attach two ten-foot pieces together and trim to the correct length.

This means that each stringer is made from FOUR 20 x 22.5 mm x 10' pieces. At this point I'm mixing Imperial and metric. Did I mention the metric scale fell off my table saw?

All of this means that now there is much work to make big pieces of wood -- 10-foot 1 x 6s -- into smaller ones: 22.5 mm wide.

Like many of these complications, sorting it out was the hard part, now it's just labor. But MAN it gets boring ripping these pieces.

1 comment:

Barbara said...

Your middle school math teachers would be proud! For us visual learners, we need pictures. P.S. I've heard calculators work well in those instances.