Sinew Bowstring

[Hartung]

I’d like to put this up to the bows forum because I’m afraid that there isn’t enough traffic in the how to’s section.

In this thread http://www.primitivearcher.com/smf/index.php/topic,272.0.html , Billy say’s that:


“When I make my sinew strings, I soak the sinew strands, then chew it so it's really soft.  Then I twist up the sinew into the string.  You will have to add splices almost constantly.  Then I stretch it, and while it's wet, I take a razor blade or a sharp flake of flint and cut off the splices that stick out of the string.  Then I let it dry with a weight tied to one end so it get somewhat pre-stretched.”


I also would like to make a sinew bowstring. And this is the shortest and yet the best how-to description that I’ve seen so far. You also say: “I've had a few failures with sinew, but I'm trying to work out the bugs”.

Please allow me to ask some questions:

1. Don’t the different strands dry out before you have finished the string?
2. Did you find out why some of your sinew had failed?
3. When you twist up your sinew, do you do a reverse wrapped twist?
4.  If so, of how many reverse wrapped strands is your string composed of?

Thanks for your help!

[jamie]

i can answer some of these. .sinew stays plenty moistby the time ya finish.
yes i use a reverse wrap
i dont count strands just keep it as even as possible and when its wet id say it is around 3/16th of an inch thick and dries to around an 1/8th inch. even my worst strings have held up longer than rawhide or some of the plant fiber strings ive made. peace

[Hartung]

“i dont count strands just keep it as even as possible”

That is interesting! Does that mean you only twist one singly ply (strand) string by taking two more or less think bundles of sinew and reverse wrap them? If that is the case that would save lots of time compared to making a string out of several strands.

[rdb]

“When I make my sinew strings, I soak the sinew strands, then chew it so it's really soft.  Then I twist up the sinew into the string.  You will have to add splices almost constantly.  Then I stretch it, and while it's wet, I take a razor blade or a sharp flake of flint and cut off the splices that stick out of the string.  Then I let it dry with a weight tied to one end so it get somewhat pre-stretched.”


I also would like to make a sinew bowstring. And this is the shortest and yet the best how-to description that I’ve seen so far. You also say: “I've had a few failures with sinew, but I'm trying to work out the bugs”.

Please allow me to ask some questions:

1. Don’t the different strands dry out before you have finished the string?
2. Did you find out why some of your sinew had failed?
3. When you twist up your sinew, do you do a reverse wrapped twist?
4.  If so, of how many reverse wrapped strands is your string composed of?

1. Last week, this was definitely the case for me. I was however making the string outside in mid 90 degree temps and a slight breeze....and, I'm slower than grandma with 4 broken fingers. At any rate, I had to keep dipping the end of my string in water as the sinew was getting stiff (dry). When I finally got the string done, the end where I started from felt completely dry and I had to soak the entire string in a bucket of water for 10 mins before hanging and adding weight for the drying process. I haven't had this problem when working inside during the winter months though.
4. Like Jamie, I don't count the strands. Upon starting, I just keep adding sinew until it's the thickness I'm looking for. I then try to maintain that thickness by grabbing the piece of sinew I think will maintain that whether it be a bit thicker piece or a highly tapered and thin strand.

Though no expert on sinew strings, it has been my experience with plant-fiber cordage that many small strands makes for a smoother, better looking and stronger string than does a string consisting of fewer and larger strands. It's more work but you get what you put in to it.

Lastly, I  have soaked then chewed the sinew prior to twisting as well as simply soaked. Chewing makes sense to me....especially if it might mean the difference between eating or not...but psychologically, I find it a tad troubling for some reason.

[Hartung]

Rdb,

Your post is very helpful too. So thank you for your contribution. Concerning question #4, ok, I know, what you mean.

I add this picture: the left sinew is pounded and pulled apart Achilles tendon with still a lot of sinew fibres attached to each other (scale is in cm). The right sinew bundle is combed sinew with a small strand (red arrow) showing how it looks like.

One more question:
5. For manufacturing your string, do you comb the sinew and than use the combed fibres? Or do you just pound and pull the sinew apart and then use these roughly pulled apart fibres for making your string?

To all the other bowyers and sinew string makers: please don’t hesitate to jump into the discussion to give us your experience.

Thanks to all!

PS: Hope your grandma is well 

[jamie]

i make two ply strings i just pay attention to thickness rather than how many strands like rdb said

[mullet]

   Just a word of caution and I know this is old news to some of you.I read quite awhile back about the dangers of chewing sinew.There was a discussion about contracting some of the deseases and parasites from Elk,Deer.I quit chewing it myself ans started soaking it in warm water.

[Hartung]

i make two ply strings i just pay attention to thickness rather than how many strands like rdb said

Does that mean that you comb your sinew into strands/threads (bundle on the right side of the pic) and then take as many strands as you need for each of the two plys until you reach the thickness you need for each ply?

Example pic #1

Two ply string composed of 5 strands for each ply



Example pic #2
Two ply string from the pic above, reverse wrapped composed of 5 strands for each ply.



Is it like this how you make your bow string?

[Justin Snyder]

You got it, but you need to staggar the ends of the five strands. That is how you keep strength at the splice. If the string starts to get thinner, not necessarily at the end of a strand, add another piece. Now none of your ends will match, and the string will be strong at the splice.  If you leave the ends even, you will have to start 5 or 6 new strands an inch before you end the first.  Then it will have a big bump in the string.That is also why you hear people saying they are constantly adding another strand.  Justin

[jamie]

what he said

[Hartung]

Do you think a sinew bowstring could be made for a 50-60# bow? How should that string look like?

I have found this statement concerning a strong sinew bowstring:

“By reverse-wrapping a string to more than twice the length of the bow, then folding the cordage in half and reverse-wrapping it again, you'll produce a strong and durable bowstring with a loop at one end.”

Would that be an option for a good bowstring? Anything to take special care of when making such a bowstring? Any other way of making a strong sinew bowstring (weaving, braiding)?

Thanks once more for all your help.

[jamie]

i have 3 bows with sinew strings that are 2 ply. all the bows are 50-55lbs. like justin said before on another post. "you can pull a truck with a sinew string". peace

[Hartung]

Very precious information, thanks Jamie.

[a finnish native]

like Jamie said it will hold. A northern Cheyenne called Strong left hand had a bow so strong he killed two Buffalo's with one arrow more than a few times. only a handful of warriors could draw his bow. by the state of these facts I'd say that it was at least 120#. and I don't think his string was from Dacron.  And remember also that Cheyenne people weren't small either. a normal man was around 74,4 inches long.

[rdb]

Rdb,

Your post is very helpful too. So thank you for your contribution. Concerning question #4, ok, I know, what you mean.

I add this picture: the left sinew is pounded and pulled apart Achilles tendon with still a lot of sinew fibres attached to each other (scale is in cm). The right sinew bundle is combed sinew with a small strand (red arrow) showing how it looks like.

One more question:
5. For manufacturing your string, do you comb the sinew and than use the combed fibres? Or do you just pound and pull the sinew apart and then use these roughly pulled apart fibres for making your string?

To all the other bowyers and sinew string makers: please don’t hesitate to jump into the discussion to give us your experience.

Thanks to all!

PS: Hope your grandma is well 

Hartung,

Sounds like you're on the right track. Another technique you might consider though is to rehydrate the whole tendon then tear it apart rather than pounding. You can read a little more about it in this thread:

http://www.primitivearcher.com/smf/index.php/topic,3024.0.html

Maybe more importantly though is to make sure each half is twisted equally and that it's as consistent as possible in thickness so there are no thin (weak) spots. It's not easy.....at least it hasn't been for me (stage fright??). I'd suggest practicing on plant fiber first....not for a bow string but for just general practice. Keep us posted on your progress.