Sinew Backed, Double Curve Bow

[a finnish native]

interesting method there. I my self do so that I rough the bow out to rough dimensions and let it dry for a month or more. then I rough it out completely and start floor tillering. then to the long string and the to brace and then to final tillering.
but hey, do it as you see best

[JackCrafty]

Finnish, it's true, my method is different.

When I first started making bows, I knew nothing about tillering.....and my bows were basically bent sticks.  Then, after reading books, articles, and forums I made bows using the method you described.  After a while, however, I began to see that I was not able to get good results with certain bow designs that placed a lot of stress on the wood.  The short, double curve design is one of them....especially when trying to make reproductions.

The first stress that the bow has to endure is the drying process.  Thinner pieces dry faster, and with less checking, than thicker pieces.  That's why I rough out and floor tiller the bow when it's green.  I low-brace the green bow and check for smooth bends in the limbs.  I also remove remove snakey bends in the stave at this point, and align the tips.  (I know that snakey bows work fine, but again, I'm making reproductions....and I haven't seen any snakey NA bows.)  I start with the straightest staves I can find, in any case.  After getting the limbs bending evenly at a low brace, the bow is thin and very close to final dimensions.  It will dry out easily from this point onward.

I let the bow rest for a day after floor tillering & low-bracing, but not more than a week, before I steam bend the handle and limbs into the classic double curve shape.  Some of the corrections from the previous bending/tillering may have undone themselves....and I take this time to re-correct those.  A floor tillered bow is a lot less stressed during this process compared to a bow that is merely roughed out.  The wood is easier to bend....and maintains the corrections better.

Then I let the bow dry out completely.

After the bow is dry, I use dry heat to make any further corrections, then apply sinew, let the sinew dry, and finish tillering.

I don't use a long string for tillering anymore, I use a slightly slack string...and I use it mainly to check on the draw weight of the bow @12".  If I see a large flaw in the bending of the limbs, I'll make the correction at this point.  Usually, at this stage, the bow is not pulling anywhere near the final design weight @12". Normally, bow makers will draw the bow back to a point where the design weight is reached, remove wood, and draw again to design weight, remove wood, etc. until the desired draw length is reached.  I don't do this anymore.  I use a chart to tell me if I'm on track to hit the draw weight at the final draw length.  This places less stress on the wood, helps prevent hinges, and helps prevent problems with the handle reflex pulling out.

It takes some experience to get to know how to floor tiller the green stave so that it can be braced (when dry) and not be too weak.

[orcbow]

Wow! Thank you for sharing the information that you have learned about these bows!

 Mitakuye Oyasin!
(We are all related!)

[JackCrafty]

Orcbow...you're welcome.  And I noticed you were up late last night?  Good.  I'm glad to see that I'm not the only one losing sleep because of this obsession.

[orcbow]

Yes I stay up late, sometimes that's the only time I get to myself. I am getting ready to start my Aragorn's Moria bow, it will be quite a bit like these bows you have made, but not double curved. I really liked getting some more info on sinew backing from you. That's going to be helpful. Winter is the time to make sinew-backed bows in Indiana, since the humidity really goes low and stays for a few months.

[JackCrafty]

Orcbow, I'd be very interested in seeing your version of Aragorn's bow.  I've wanted to make one myself...and now that I've got more experience I think I'll make one soon.

The three main questions I will need to decide on are bow weight, material, and brace height.  The size is pretty obvious.  What are your thoughts?

Legolas's bow was probably a lot more powerful than Aragorn's....there are at least two times where Legolas nails an orc in the skull....whereas Aragorn tended to shoot at the neck.  I would estimate Aragorn's Moria bow at about 70#....and Legolas' Moria bow at twice that.

The material might have to be ipe or some other tropical wood that allows for a very narrow profile....probably backed and then coated with black pitch for waterproofing.  The only puzzling thing is the thick tips.  (You can get away with extremely narrow tips with ipe).  Hmmmm.....I might try juniper just for grins.

The brace height seems high (from what I remember).....maybe 6" or 7"?

Overall, his outfit resembles Plains Indian style equipment.

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[orcbow]

I think you are right on with the weights on those bows, I think that some of Legolas's long shots would only be possible with a bow up in that range. Personally, I would not want to be in that situation in the Tomb of Balin with less than a 70 # bow. But of course, it is a movie, still it's a fun exercise to try to do the bow design work. Aragorn's bow is really quite narrow in some of the views of it (I would guess 5/8-3/4" wide)

The brace height is quite high, probably to help prevent wrist slap, when dry firing. 7" easily. But it looks different in different parts of the movie.

The best view of the bow comes from a scene just after Gandalf falls into the pit after the Balrog. That's the view were I got a good scale sketch. I came up with 42" long. Unfortunately I could not find any screen shots of that scene.

I am going to try cypress actually. And sinew back it. It may not make 70# though.

[JackCrafty]

That's an awesone picture....it really shows his equipment in good perspective.  I had forgotten how the fletching looked like....looks like spiral wrapped and somewhere between 3" and 4".  The arrowhead looks really long and narrow....a bodkin type?

With a 42" bow, I think we can get a 22" draw with the right backing...and you're right, the 70# weight will be a challenge.

[JackCrafty]

OK...I think we digress here.

We've finished the move into our new house, so.......this weekend will be the first time in a couple weeks that I will have time to get back to work on the double curve bow.  I'm going to make a test arrow, shoot the bow, do the final tillering, record the stats, and apply the finish.  Cross my fingers and hope there are no interuptions.....

[orcbow]

Yes ,I think its a digression, but bringing it back to your original subject, I think its fair to compare this fantasy bow to a plains style bow. I will start a post of my own soon about this bow. Thanks for humoring me with this little side discussion!

[JackCrafty]

Any time Orcbow!  I look forward to your post.

[bootboy]

Aragorns bow is hard to find good photos of. I have been trying to find some myself to make it. In the movie it seems pretty powerful for such a small bow, he took a deer with it, and shot orks at retarded ranges. The bow itself looks really pretty to boot. This should be a lot of fun.

[JackCrafty]

Last night I finished tillering the bow.  It didn't need much....just a slight bit of wood was removed from the belly of the upper limb to remove a flat spot.  I'll take pics tonight or tomorrow.

For now, I'll post some data.  Here are the draw weights of the bow during construction (in chronological order):

October 5^th (reply#57), Draw weight = 29.8# @ 12" (after 1st layer of sinew dried)
October 5^th (reply#58), Draw weight = 27.9# @ 12" (after initial tillering)
October 11^th (reply#65), Draw weight = 27.8# @ 12" (after sinew dried for 1 week)
October 21^st (reply#58), Draw weight = 29.3# @ 12" (after second course of sinew dried for two days)
November 18^th (last night), Draw weight = 33.7# @ 12" (before final tillering and after sinew dried for about 1 month)
November 18^th (last night), Draw weight = 30.3# @ 12" (after final tillering)
November 18^th (last night), Draw weight = 30.2# @ 12" (after slight exercising - i.e. drawing bow 25 times)

Draw weight = 52.4# @ 18".  The final draw length will be 20" but I will exercise the bow out to 21".  It should be close to 60# @21"......almost reaching the final draw weight that I planned for this bow.

Mass of bow on October 21^st = 14.55 oz.
Mass of bow on November 18^th = 14.15 oz.

As you can see, the draw weight has increased due to the sinew.  This is a surprise for me, as I have not seen this before.  I thought about this last night (i.e. lost about an hour of sleep ) and I think it has to do with the change in my environment.....it's really dry here in West Texas.  Prior to this, I built all my bows in a high humidity environment, and without a hot box or moisture meter.  The layer of sinew is about 1/16" thick and increased the draw weight by about 13%!  (from 29.3# to 33.7# after a month of drying)

[JackCrafty]

Final tiller.

(picture is a view of bow drawn to 18").


I have not exercised the bow out to 20" yet.....and I won't take a picture at full draw (when the bow is on the tillering stick).  Normally, I don't hold the bow at full draw for more than second or two.

I shot the bow last night several times with a test arrow.  It's very fast but has a little more hand shock than I expected.  I will chronograph the speed later.

Now I will focus on improving my finger strength (this bow is more powerful than my other bows) and applying the finish.

[orcbow]

Nice....I am impressed!!!!