So, this week is the ideal time for the post about Sewing, because gid is something scribes run into quite a lot. Scribal gid - "sinew" - is tendons; animal tendons, of course, not people ones, spun with glue.
New sheets of parchment come as single sheets, not as one big roll, and one sews them together after they've been written. People ask incredulously "Do you sew them together yourself?" I don't understand whence the incredulity, honestly - is it part of the Brave New culture which doesn't mend but buys new? Yes, one sews them together oneself. Much easier than sewing on a button, and in any case, compared to how much work the writing is, the sewing's a breeze.
Before sewing, I make the holes for the stitches with an awl, rather like a shoemaker would. The stitches go through twelve holes, one for each tribe of Israel. They make eleven stitches, one for each allotted tribal portion in the Land of Israel. The tribe of Levi, the priests, did not have land of their own; they lived throughout the country, uniting the other tribes by creating a holy presence all through the land. So too the thread moves from stitch to stitch, uniting them together in a seam, uniting the sheets of writing together as a scroll. Without the seams, the Torah is fractured, Israel is divided, even if all the words are there.
Note: This is custom, not law. Technically, there is no given number of stitches to be used in the seam, provided there are some at the top, middle, and bottom. I like the above interpretation, so that is how I am making my seams, but a seam with a different number of stitches is not invalid. It is important to be clear about the distinction between custom and law.
The stitches are essential, and just as holy as the letters. It follows that just as there is a special declaration of intent to be made before writing, there is one to be made before sewing. One has to be conscious of doing the job specially for this particular Scroll - it's not just any old sewing, any old scroll - it's THE sewing, THE scroll. Accordingly, there's a custom to use a gold needle, because gold is the metal of kingship, and other metals are mundane at best, and at worst associated with harmful things like war and commerce.
And after all that build-up, the seam itself is just an ordinary (if large) running stitch. You sew wrong side out, just like you would any sewing, you knot the thread and do a backstitch at either end, like any sewing, and afterwards you turn it right side out and press the seam, like any sewing. Except you use a bookbinder's tool, called a bone folder, not an iron.
So what about the gid ha-nashe?
Gid in Hebrew means a number of things. "Stringy bits," basically - "gid" as a non-specialist term includes tendons and ligaments, also veins, arteries, and nerves.
Keset ha-Sofer, our friend the scribes' rulebook, says that one shouldn't use the gid ha-nashe, the sciatic nerve, to sew Torahs, since we are forbidden to eat the sciatic nerve, and we don't make Torahs out of things we're forbidden to eat (note: this is law, and not just custom).
There's also a practical aspect: nerves just don't make good thread. Tendons and ligaments make the best thread because they have oodles of collagen in them. Collagen is fairly bouncy stretchy stuff even when it's dried out, so tendons are good and flexible and make a good thread. Veins, arteries, and nerves aren't built like that, so when the component cells die the strings go brittle, and wouldn't be much use for sewing.
Along similar lines, if one doesn't have any gid for sewing, and it's a real emergency, one may use thread. The author of the Keset ha-Sofer says it's better to use flax thread than silk thread, because of the principle that we don't make Torahs out of things we're forbidden to eat, and silk is made from worms, which aren't kosher. The silk itself isn't exactly non-kosher, but it's apparently a bit too inherently wormy for his liking. But he's Ashkenazi - living in Europe. You occasionally see Torahs from China sewn with silk - perhaps greater familiarity with silk gave them a different perspective.
Something a bit different to think about during this week's reading!