Main Discussion Area > HowTo's and Build-a-longs
Sinew Backed, Double Curve Bow
JackCrafty:
OK, the bow now has sinew applied to the sides and it's been drying for a few days.
I got a little too zealous and put sinew too high on the back (in the handle area) and the sinew separated from the back.
(Note: I did not wrap the sinew with twine this time.)
So I just trimmed it off with a knife. This did not affect the first course of sinew.
Sanding the remaining sinew "hight spots".
I checked the alignment of the tips and, sure enough, the wood has "remembered" some of it's original shape.
(I guess the moisture in the sinew affected the wood?)
Anyway, the original shape was much worse that this, so I guess it's not too bad.
I just hope that it doesn't change much during final tillering.
I added a second course of sinew to the back and let it dry for a few days.
(The second course was not wrapped with twine)
I didn't apply the sinew to the handle area...just the limbs.
I hope you can see that there is no second course of sinew over the handle area in the pic below.
Lower tip with sinew on back and side.
Other tip.
Sanding rough spots on second course of sinew.
The second course is not as important as the first, so I'm not too worried about sanding through the fibers.
Wrapping the lower tip with sinew & glue.
Adding shoulder nock.
Applying layer of glue (straight from the bottle) over the second course of sinew.
As you can see from the last pic, I wrapped the limb (about 1" wide). I did this to cover a small splinter on the belly. Then I wrapped the other limb for symmetry. Then I remembered that I hadn't finished the tillering (OOPS!)....oh well. ;D I'm hoping the final tiller looks good. If there is a problem, and I have to remove the sinew wrap (to scrape wood off the belly), it's no big deal.....just kind of a pain. I'm crossing my fingers.
donnieonetrack:
Patrick, what's the purpose of the sinew on the side of the bow?
thanks,
Donnie
JackCrafty:
Heck, I dunno. ;D It looks cool?
As far as I can tell, the sinew on the sides helps to strengthen the "corners" of the bow's cross section. I think it also helps to prevent splitting along the sides where the grain runs out. Most of the original sinewed bows had rounded backs, and tapered very gradually from handle to tip, so most of them didn't need sinew on the sides. I put sinew on mine as a safety measure because this stave was not of the best quality.
JackCrafty:
The sinew wrapping has dried for a couple days....and I'm getting a little impatient...so I strung the bow with the new string and shot it about 20 times at 12" draw (last night).
Here's the bow braced with the new string:
Sinew wrapping on the handle area (back):
Sinew wrapping (belly):
Upper tip:
Lower tip:
Braced view from one end:
Brace height 4-1/2":
OK, 1st reading @ 12" draw:
2nd reading:
3rd reading:
12" draw
Bow unbraced:
The last reading @12" draw was on Oct 11 (reply #65)......and was 27.8 lb.
Currently the draw weight @12" is 29.3 lb.....gain of 1.5 lb.
(This data was corrected on 11-19-08. I previously showed no increase in draw weight)
Weight (mass) of bow: 14.55 oz.
Mass before sinew was 12.9 oz.
Mass of string: 174 grains (0.4 oz).
Strings should be no more than 3 grains per 10# of draw weight (TBB).
So, a 55lb bow should have a string of no more than 165 grains.
This string is 61" long but the nock-to-nock measurement is 46".
So.....the actual working part of the string is lighter than 174 grains:
174/61=2.85 grains per inch x 46"=131 grains. This is well under the 3 grains per 10# limit.
There's already a little wear on the loop from bracing/unbracing.
It usually doesn't get much worse than this.
The loop area is pretty thick anyway and can handle the wear.
I'm going to let the bow dry for another week before I mess with it again. ;D
JackCrafty:
The next thing to consider, at this point, is the final look of the bow. I'm thinking of going with a replica of a Blackfeet bow that I saw in Jim Hamm & Steve Allely's book (It's listed as Blackfoot in the book). Here's a picture of that same bow (?) from the Division of Anthropology (AMNH) site:
(It's listed as a Blackfeet bow on the AMNH site)
Dimensions:
L = 113cm (44-1/2" tip to tip)
W = 8.2cm (3-1/4" from back of bow to string)
H = 3.2cm (1-1/4" wide at the handle)
The bow appears to be painted black (or brown) with red bands....with a braided hair ornament tied to the upper tip.
(The AMNH site says that there is a skull "carving" with the bow. I guess there is a small carved skull effigy hanging alongside the braided hair?)
Anyway, I'll need to cut off the extra wood from the upper tip of my bow so that it will look more like the one in the photo.
I will also make a quiver similar to the one in the photo.
Whatcha think?
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version