My horn bow build-a-long

[JNystrom]

Before sinewing, wood and horn only.

[DC]

OK that makes more sense. I was thinking you just meant wood only. Happy now

[DC]

More shaping today. I finally had to bite the bullet and settle on the thickness. It was a tough decision. With input from bownarra, JNystrom, The Book and a couple of threads from the German website "Fletchers Corner" (Thanks Simk)I was able to make a WAG and fly at it. The Readers Digest version is that the thinnest part in the eye will be/is 7.8mm and thickens toward the handle. I have no idea what draw weight I will get but it's looking like 40-45#. I'm in the process of joining the Fletchers Corner. I don't speak German so I'm getting Deepl(a translation program) and will run all my communication through that. There's at least a half dozen guys making horn bows there. As far as reading the forum the Windows translator works quite well and I've only had a couple of times in hours of reading where I've been stumped. I'm not sure how it will work with a two way conversation.

[DC]

Here's a picture with a tape. I took 6 pictures and this is the clearest(old shakey hands). Harsh criticism of every detail please   I'm thinking it might be a little thick in the 5-15 cm range.

[gorazd]

I think you should thin down the sal area between 10cm point (from centre of the bow) and first nut.....  and make the SAME thickness at least 15-20cm long to achieve nice bending of the limb.
And maybe thin down the area between first and second nut too...

I used the caliper ruler - and marked the points - and achieved 0,1mm accuracy when sanding the wood.
Sanding the wood:
I used the 100 grit sand  paper on the small sanding block  ....  for best accuracy.
Of course .... before sinew job I roughed the wood with piece of old saw blade.

[DC]

Thanks gorazd The area around the first nut is around 8mm thick(3.5 horn and 4.5 wood) and 23mm wide. The handle is made from Ocean Spray, a very hard, dense, stiff wood and the end of the "V" joint is at the 16mm mark. My limbs are almost parallel, 24mm tapering to 23mm at the kasan/tip bend.
So should I be going down to 7mm from the second nut going back 15-20cm toward the handle or should I be down to 7mm at the 10cm point?
Sorry for all the questions, I don't want to mess up now and dump 4 months down the tube.

[gorazd]

Here is it :

"https://i.imgur.com/Tv4zuhF.png"    -  to make the bow bend more near the handle...

And ... I would recommend to thin down the section marked with red too - and make shorter kasan ....

[DC]

Great, thanks. I've been lurking on the German forum "Fletchers Corner" and I'm waiting to get accepted there. There is some mention of test bending before sinewing on there. Have you heard of that?

[gorazd]

Yes, I have heard about test bending before sinewing.
But I did not try ...

I used bamboo wood core and did test bending of the 5mm bamboo only - around the same bending raidus as future turkish bow - the bamboo survived, so I correctly exppected that 3mm core wood in composite would be no problem even I put sinew in thinner layers ...

Great, thanks. I've been lurking on the German forum "Fletchers Corner" and I'm waiting to get accepted there. There is some mention of test bending before sinewing on there. Have you heard of that?

[DC]

Time to start sorting sinew I guess. It's all shredded so it's just make piles and weigh out clumps. I'll save the final shaping for the last minute so I have fresh wood.

[bownarra]

Here are the measurements from my 40ish# bow. 121cm.
Center - 33mm
5cm  - 26mm
10cm - 14mm
15cm  - 10.4mm
20cm - 9.6mm
25cm - 9.1mm
30cm - 8.9mm
Kasan eye 35cm - 9.5mm
40cm - 12mm
45cm - 13.5mm
50cm - 14.5mm
Base of tip 52cm - 17mm

[bownarra]

It's a fast bow
I'll take some pictures this afternoon of it unbraced and braced. So you've got something to aim at.

As for bending just before sinewing yes you can do it and it is useful but you must bend the bow backwards, bending it the correct way any appreciable distance will of course break the core at one of the many grain violations
Of course bending it backwards needs an eye for what the correct shape of a sinewed bow is when it is tied up for seasoning.....on this first bow just make absolutely certain you have a perfect taper with not even a hint of a thin spot anywhere and you won't be far wrong.

[DC]

Thanks bownarra, especially for the measurements. Something that's been puzzling me. Is it the total thickness of the limb that determines the DW(ignore length and width for this) or does the percentage of each layer have some effect. Would a bow that is 10mm thick have the same DW whether it was 1/3,1/3,1/3 or maybe 1/4,1/4,1/2. Within reason of course . Adam suggests adding extra sinew on your first bow, isn't that going to increase the DW?

[DC]

Here are the measurements from my 40ish# bow. 121cm.
Center - 33mm
5cm  - 26mm
10cm - 14mm
15cm  - 10.4mm
20cm - 9.6mm
25cm - 9.1mm
30cm - 8.9mm
Kasan eye 35cm - 9.5mm
40cm - 12mm
45cm - 13.5mm
50cm - 14.5mm
Base of tip 52cm - 17mm

How much of that is sinew do you think? Rough width of limb? It's very similar to mine in general measurements but my eye is at 30ish.

[DC]

Today I'm organising my sinewing setup. Building a rack to hold the bow, calibrating my hotpot. Figuring out what length and how much sinew to put on the first coat. That kind of stuff. With any luck I'll do the final thickness sizing of the bow this afternoon and then maybe a couple of coats of glue sizing.