Silk thread for tying fletching and broadheads on an arrow?

[red hill]

This summer I've made a few arrows using river cane, turkey tail feathers, artificial sinew, and duplex head nails.

I pulled the artificial sinew apart to reduce the diameter as much as possible. The first arrow I made was tied with the full diameter artificial sinew and it looked pretty glumsy.
The others, tied with the thin diameter strands, look much better.
 
My question is what diameter silk thread should I look for?  I found a website that carries silk thread but couldn't find a diameter key to help make a decision.

The artificial sinew works well, I'm just asking for possible future use.

[Stiks-n-Strings]

Red I have used silk thread for the same thing and just grabbed the stuff that was close to regular thread.

[Grey Taylor]

I used to use Gudebrod "00" silk thread made for wrapping the guides on fly rods. Sadly, it is no longer being made after Gudebrod went through some changes.
There are some other silk rod wrapping threads being made but I haven't had the chance to try them yet.
These days I've been using nylon rod wrapping thread in size "A" and it works fine. "A" is fine enough so it looks like paint or tape if it's put on properly and finished yet it's not so small a filament that you go blind working with it.

Guy

[dmikeyj]

Joanne's fabrics has silk thread made by Gutermann, I use the black, #CA02776, not sure on the size, but it is perfect for fletching.  If I remember correctly, the spool is 100 meters, and it was around $4.50.

[red hill]

The website I visited had sizes in numbers and then sizes in letters. There was even a 0000 size.
I'd heard of 00 diameter but didn't see it.
So, thanks, guys. I think I'll order the size A. It comes on a spool and should last quite a while. And it'll probably be black.

[monterey]

I just did the sil thread and fletch for the first time a couple weeks ago.  Used it to tie some full length fletch on an atlatl spear.

I used red silk that I retrieved from my fly tying gear.  Any fly shop that has tying supplies will have various diameters of various colors of silk thread.  

The stuff I used was very fine and worked good.  You can always wind more of the fine stuff on, but as you found with the full diameter sinew, it can get too thick.

I finished with some very un-paleo super glue!!

[red hill]

Yeah, I use the super glue also, Monterey.

Down here in south Arkansas we don't have fly shops. About the only need for fly rods is bream fishing... blue gills mostly... and not many do that anymore.

[David Flanrey]

Red, when I tie on points I use deer backstrap sinew or dried gut.  You can die it any color you want and it dries translucent and super hard.  Put glue on it if you want for a moisture barrier.

[Roy from Pa]

Three Rivers used to carry silk, but no more. I'll have to check out Joanne's fabrics. Thanks, dmikeyj