My horn bow build-a-long

[DC]

I'm trying this. The light bulbs are heating the belly to just under 50°c. I fiddled with the distance until it was right. Now I can just let it soak. I'm checking the temp every 5 min. It's been going a half hour or so. It's just hanging on the pegboard. Maybe kinda Rube Goldberg but I've tried all the other ways I can find.

I let it heat for 1 1/2 hours. The back was at 45+°c for most of that. See what tomorrow brings.

[DC]

Bownarra, I remember you saying way back that something about the shape of this bow was going to cause me trouble down the line. This is a picture from right after I glued the horn on. Is it possible that the glued in reflex in the sal area is whats stopping it from straightening out as much as I want. I've done everything you've suggested and more and it doesn't want to open.

[DC]

I decided to bend it and live with the consequences. It doesn't look too bad to me but what do I know about these things. Should I move the peg holes out a little further? I really think I've just got one more hole to go to get to brace height. I'll paint the board black so I can see things a bit better.

[bownarra]

Yes what you've done would have been my next suggestion! Bend it further to see what is going on. Yes I think you are right about the sal reflex/core shape.
Now that it is bent on the pegboard the kasan eyes have opened, can you see that area bending when you bend the bow on the board? The sals look to be bending a little too much close to the handle but with the reflex in the sals having to straighten out first it may be misleading. If you leave it sat like this for a while the temporary set you will see when you take it off the board will tell you where it is strained or not. Having the bend a little closer to the grip isn't a bad thing really as it will make the bow a little more stable, easier to string and won't stack as early. You do get more set in the inner limbs but that isn't a big deal.
Pegboard holes look to be in a good place on the bows limbs. I would drill two more sets of holes. One as far down as you can drill and an intermediary one.
You want to brace it at around 7 1/2 inches initially. They can be a bit 'wild' on first brace! Have the sections of inner tube to hand....
Once you add the holes to the pegboard take some more pics. I think the next set of holes will help to reveal how to proceed.

[sleek]

I'm following closely,  and every post has me waiting with baited breath!

[DC]

OK here ya go, can you see behind my hand in the first pic how much more the "eye" is bending compared to the next pic when it's on the peg. The same shows on the third and forth pic only not as much. I'm thinking that when I get it braced the left eye will be bending quite a bit more than the right. Leverage. I don't think the pegs allow the true shape to show. That's why I drilled the outer holes.

[DC]

Does this pencil mark look about right for the nock? It's 7 cm from the the kasan tip bend apex.

[DC]

Here's one with the pegs in the outer position. It's quite different and kind of unnerving.

I'm thinking I have to scrape at the red marks. Just in between the weak spots on the left limb and more or less the whole thing on the right

[bownarra]

Before I comment on the tiller. Could you measure the limb thicknesses every 5cm on both limbs and post what you've got.

[WhistlingBadger]

It is so cool watching this unfold (quit literally!) DC.  Thanks for sharing your process.  It's fascinating.

[DC]

It is so cool watching this unfold (quit literally!) DC.  Thanks for sharing your process.  It's fascinating.

Well it's pushed me to the limit a few times. I'm glad I started this thread otherwise I may have abandoned it. Pride does have a use sometimes

[DC]

Before I comment on the tiller. Could you measure the limb thicknesses every 5cm on both limbs and post what you've got.

OK I hope you can read this. I got the crud and just don't feel like typing a bunch. Left hand side is what I measured. Then to save time I did a little fixing and the right hand side is the after. The picture is after. The discrepancies were minor most were just little ridges in the sinew that I missed. I seem to be having computer troubles so if I disappear for a few days I haven't jumped in front of a bus or anything.

[stuckinthemud]

It is so cool watching this unfold (quit literally!) DC.  Thanks for sharing your process.  It's fascinating.

what he said. I've learned so much from this thread, thanks for posting!

[JNystrom]

I think you should really concentrate the bend on the first 1/3 of the limbs. Now the outer limbs are bending way too much. I hope you got some poundage left on it. The beginning shape doesn't really show much kasan eye angle, so the final bow wouldn't show it that much anyway as a more "normal" turkish shape.
It looks like the bow in general likes to bend, even the kasan parts so you have gotten past the worst part!

Here is some measurements of some of my bows, a typical turkish: limb next to handle 13mm thick, mid sal (most bending part) 12,2mm, kasan eye 11,7mm and from there quite fast growing to  kasan 15mm. 

Just to remember: horn and sinew will stand a lot of bend. You will get speed (efficiency) and balance in the bow if you concentrate the bend more. Even a momentarily hinge that would "destroy" wood bow, wont do much to hornbow. Also, if you make the bow bend too much from outer parts, you will end up keeping an awful lot of reflex and the bow will be hard to brace.
Anyway, its close to brace, you will do fine.

Oh and about the nocks, 55-70mm from the end of kasan was normal length. So what ever you choose. Of course you can scale it to your liking, for short bow (40") a 55-60mm is fine, longer (46") 70mm. Crimean tatars were longer bows with lengths about 46-54" so they had quite much longer, 80-90mm nocks.

[DC]

I thought I would put a full group of pictures on this page. I leave the stretcher bar in all the time now. I can see that the right sal has more reflex bend than the left.(Edit-or maybe it is in the eye) What should I do about that if iI shouldn't heat the sal. The weight will be what the weight will be. I can only pull 40# and it feels like it will make that but what do I know. These things change a lot as you bend them.