Saturday, January 26, 2008

Sailmaking: Machine Work Complete on the Jib

I had put the sailmaking project aside for awhile but this morning I finished all the machine sewing with the completion of the luff wire installation. The leech edge, shown above, was much easier than the luff, since there was only a small Dacron cord in it for the leech line. Sewing the heavier coated steel wire into the luff was more difficult, due to the fabric wanting to distort and bunch up as it entered the machine. You're supposed to be able to sew the luff tape sleeve first with just a small messenger line inside and then pull the wire luff through, but due to the size of the swaged eyes on each end of the wire I couldn't do this and so had to sew the sleeve with the wire in place.

After both outer edges of the sleeve are sewn to the sail with a zig-zag stitch, entrapping the wire, a roping/zipper foot is then put on the machine to allow it to sew a tight line of straight stitches right behind the wire, which makes the edge look finished and neat and keeps the luff wire right out front, on the leading edge where it's supposed to be. This operation is shown below:

Here's a short video clip as well, showing the same operation, making the tight line of stitches just behind the luff wire with a zipper foot installed. You'll notice I'm having to start and stop a lot. This is so I can keep forcing the wire out front, smoothing the luff sleeve and making sure the stitches are going right behind the wire as close as possible. Also note the less than ideal conditions; working on the floor and having to use my hand to operate the foot switch. Not the best situation, but it works, and with this sail nearly done, I'm looking forward to building the mainsail.

Here is a view of the tack corner of the sail, showing the installed luff wire after this row of stitches has been run. Also note that the eye in the end of the wire has been let into the leading edge of the luff sleeve by cutting it back a bit. It was then hand sewn in place with heavy sailmaker's twine. The next step will be to install a sewn brass ring just inside the corner a bit from this eye, then the ring and the eye will be joined together with many more hand stitches. The sewn ring spreads the load into the heavily-reinforced corner patch. The same thing will be done at the head of the sail. This hand work requires a considerable amount of force to push the large needle through all those layers of 7.5oz Dacron. A sailmakers palm helps a lot. More on this hand sewing in a future post:

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