Sinew Backed, Double Curve Bow

[JackCrafty]

It appears that this new piece of juniper isn't as stiff as I had hoped.  Unfortunately, it's hard to tell with juniper...there is a LOT of variation in the wood.  I think I'll have to oversize the next one quite a bit to get the 60# I'm shooting for.

If this is helping anyone let me know.  If you're confused, or if I left out something, (or messed up) let me know that too.

I will be working on the bow again this next weekend.

[Postman]

Great buildalong - out of curiosity, do you think a thick-ringed piece of osage could be done in a similar style/weight unbacked?

[JackCrafty]

Postman, sure.  Unbacked osage was a favorite bow design of Comanche and Kiowa Indians. As long as you start with a sound piece of osage (not too knotty or snakey) that doesn't have too much of a crown on the back, you should be fine.  I would go a little longer though...maybe 50-54"...or longer if you want a draw more than 24". It's best if you start with a fairly green stave of osage for the initial steam bending and then let it season to "lock in" the shape, but I've used cured staves as well.  I've also used staves with a lot of sapwood but they are not as snappy as a heartwood stave.  IMO, thick rings make it easier to chase a ring, but try to be as careful as possible because this design puts a lot of strain on the wood.

[Postman]

cool - thanks  - I have some green osage that's a little short - gonna try a 54 or so incher.

[JackCrafty]

I worked on the bowstring a little today.  I added some pics to my "Sinew Bowstring Technique" thread that I posted a while ago.  Here is the bowstring (partially completed) with a clamp placed on the strands to keep it from unraveling.

[JackCrafty]

This pic shows the draw weight of the new juniper bow @12" draw.  It's been drying for a week and I'm going to add another course of sinew (today and tomorrow).  I was just curious to see if the bow had picked up any weight.  It appears that the draw weight is about the same as last week (it was 27.9 lb@ 12" draw six days ago).


OK, I'm going to show off a bit by posting some pics of a couple of sets I made a while ago.  (They have been put though a lot of shooting and the stings on the bows have been replaced recently.)  Anyway, since I was curious to see the differences in these bows compared to my new juniper bow, I thought I would take some pictures.  The differences I'm concerned about are things like stack, hand shock, loss of draw weight while shooting/exercising the bows, wrist slap, and overall performance.


The following are pictures of two matched bow & arrow sets and a quiver made of suede.  The upper bow is unbacked hickory (stained yellow) and the other is sinew-backed mulberry.  The quiver was made for the mulberry bow & arrow set.







This pic shows the upper limbs and bowstrings (close-up).  The upper string (on the hickory bow) is made of sisal and the other is sinew.



Pic showing both bows braced.
(They are both braced a little high to reduce wrist slap)

[JackCrafty]

So....I measured the draw weights of these two bows @12"....three times each.  I knew these two needed to be "warmed up" before shooting (because they loose draw weight) but I didn't know exactly how much.


Here's the first three readings on the mulberry bow:






And the first three readings on the hickory bow:




The mulberry seems to lose more draw weight than the hickory.  (Mulberry lost 4% and the hickory lost 3.5%)

Something else I've noticed is that these bows seem to have a bit of positive tiller?  Interesting.  I didn't really know what positive tiller was until last week (or so).  I think the fact that I tiller my bows to look "right" when I'm looking in a mirror (at full draw) is causing this.

Here are the first three readings on the older juniper bow @12" draw:



The juniper loses about 1.5% of draw weight after a few draws.
(Quite a bit less than the hickory or mulberry).



Close-ups......Upper nock on mulberry bow

Upper nock on hickory bow

Sinew near handle (mulberry bow)

Sinew backing, upper nock

Sinew backing, lower nock

[orcbow]

Thanks for posting all of this great info. I really want to try again to make another one now that I understand a little better the reasons behind the design. That fish glue seems a whole lot easier than the mess of hot hide glue that I have used!!!

By the way are your quivers and bowcases made of brain-tan? The color and texture looks like it, but the pictures are not that detailed.

Nice work!

[JackCrafty]

Orcbow, the fish glue is definitely a lot easier to work with.  Ishi used fish glue...that's where I got the idea.

The quiver you see is made of "moccasin weight" suede from Tandy Leather.  It's inexpensive and tough.  I wish I could afford braintan.

I've got a new camera now but I'm still learning how to use it.  Hopefully this weekend I'll be able to post more detailed pics.  Sorry about the poor quality so far.

[Papa Matt]

Patrick--Do you recommend fish glue over everything else? I ask because they say Knox gelatin is real good and strong-not to mention cheap. Is the fish glue that much better, if at all, so as to justify the greater expense?

~~Papa Matt

[JackCrafty]

I haven't used knox (yet) so I don't know how it compares to fish glue (or hide glue) as far as ease of use.  There is a lot on reliable info that says knox is very strong.

Personally, I use fish glue for everything involving sinew...and also for primitive paint (it's called distemper paint and artists have been using watercolors based on fish glue and pigment for hundreds of years). I think it's well worth the expense.  Do I have your address?  Shoot me a PM....I'll send you a sample so you can try it.

[Papa Matt]

Pat, that's awesome of you to offer, but you don't have to put yourself through all that trouble. I'm just asking because in the near future I plan to sinew-back a bow, and it will be my 3rd attempt at it--my first two were poorly done because I didn't know half of what I know now, and they ended up being worthless. On my first attempt I used liquid hide glue which never dried and on my second I boiled some sinew scraps and leather to try a glue from that. So I'm just trying to more or less figure out what glue to use. I already have the sinew. I might try Knox since everybody says it's good stuff and so strong--and best of all only like 50 cents a box.

~~Matt

[JackCrafty]

Sounds good.  Let me know how it turns out.

[orcbow]

I wish I could afford brain-tan too! So I learned how to make it myself, you could too, Jackcrafty! If you can make bows and arrows like these! Fine work, I say. But brain-tan is really simple, although quite time consuming. And you don't even have to use brains...

For what it's worth, Papa Matt, I have used Knox glue a lot , and it is quite good and strong (and very cheap). But its maybe not as easy to use as fish glue.

[El Destructo]

Patrick....where you buying your Fish Glue? And as for Knox.......buy Hide Glue........it isnt the same........ask anyone that restores old Furniture.....or String Instruments....they would never waste their time with J-E-L-L-O