dimensions crimean tatar bow

Botondbow · Post by **Botondbow** » Wed Nov 14, 2012 12:28 pm

Uli wrote:pictures follow..

Wow, it looks great, thanks!

alex27 · Post by **alex27** » Sun Dec 02, 2012 5:38 pm

I glued the horn strips almost 2 weeks ago, and am shaping the core.

Projected dimensions for core+horn now are as followed:

Grip: 18-20 cm long, 28mm thick, 24mm wide
Sal: 30-31 cm long, 9-10 mm thick, 34mm wide
(thinnest part little less than 9mm)
Sal/Kasan: about 9mm thick, 33mm wide
Kasan: 20 cm long, 9-17 mm thick, 33-24 mm wide
Kasan/Tip: 17mm thick, 24mm wide
Tip: 12-14 cm long, 19mm thick, 13 mm wide

What keeps me from going on is where I should make the thinnest part on the sal. I made a sketch where I think I want to make the thinnest part, it's about 10 cm from where the grip fades. That puts it at 1/3 of the sal.

Should the thickness increase from thereon towards the kasan eye? Zoran Pavlovic's dimensions tell me yes (thickness at sal/kasan is 2.5 mm more than at sal bendingsection), but it feels contradictionary. It would make the kasan quite stiff or not?

Anyways, In about 2 weeks I will start with the sinew part. Plan is to add 80-100 gram of sinew on the bow, will probably be about 3mm more thickness(without the ridge). Hope to finish somewhere at 70-80 lb.

Uli · Post by **Uli** » Mon Dec 03, 2012 1:21 am

I suggest to pre-tiller the core only once the horn is glued on.
That will avoid loosing horn later on.
Taper the core tickness from grip to the kasan eye as the thinnest point.

see picture (although this is quite an unusual bow it gives you an idea)

Adam Karpowicz · Post by **Adam Karpowicz** » Mon Dec 03, 2012 11:19 am

When you make the sal bend so close to the grip, the bow will be overstressed. I suggest to move the thinnest point about 2/3 of the way towards the kasan eye. In Tatar bows I examined, the thinnest spot was about there - not at the kasan eye as in the Turkish bows (an per Uli's advice). These bows are longer than Turkish and do not need the bending section maximized as much.

I would be very cautious about bending the bow without sinew, since the wood grain is cut through on the back in the core over most of the length.

Adam

Uli · Post by **Uli** » Mon Dec 03, 2012 11:40 am

.. trust the master

alex27 · Post by **alex27** » Mon Dec 03, 2012 7:41 pm

Thank you for the advice!
As I am more a visual person I added another sketch.
The green zone would than be the thinnest part on the bow as you suggest Adam? How large is would it be, about 5 cm?
I added my suggested thickness of the core+horn. Please feel free to correct!

Uli: I am always a little bit cautious pre-tillering the the core+horn. Although this bow has edge-ringed heat-treated ash, it should work.
I'll think of it, maybe give it a try. The horn should be glued on correctly, but you never know.

Adam: It seems unlogical to me that the thinnest part is so far away from the kasan eye, as in turkish bows. Does the kasan straighten out in these bows like in turkish bows? The idea of the thinnest part is to help this straightening out, isn't it?

alex27 · Post by **alex27** » Mon Dec 03, 2012 7:43 pm

Uli
Is this a museum bow, or one of your own bows?

Adam Karpowicz · Post by **Adam Karpowicz** » Tue Dec 04, 2012 12:35 am

Yes, the taper seems OK as drawn, although I am not quite sure if the 12mm at the fadeout is enough for the thickness (that depends how you define the fadeout).

"Does the kasan straighten out in these bows like in turkish bows? "

No, since the limb bends less above the thinnest part, these bows flex less in the kasan eye and do not straighten out as the Turkish. I say this, because the bows I have seen so far had this particular taper, but I am sure there were exceptions.

"The idea of the thinnest part is to help this straightening out, isn't it? "

The limbs bend, thanks to the correct taper, up to and including the thinnest part. Beyond that, the limbs bend much less or not at all.

Adam

alex27 · Post by **alex27** » Tue Dec 04, 2012 4:59 pm

Adam thank you for the information!
The 12 mm would be where the grip ends, but it's an estimate, I have to see while shaping.

Could I interpret it like this?
The crim bow is longer and will not have the extreme bending forces in the sal area as turkish bows have, and therefore the kasan straigthens out less.

Adam Karpowicz · Post by **Adam Karpowicz** » Wed Dec 05, 2012 10:54 am

Yes, but it also depends on the relative lengths of the sal and kasan. The kasan length of the bows I saw was rather short, so the sals were longer. On the other hand there were bows with longer kasans - look at the picture above of the old bow (not red). With a reasonable taper and thickness, the limbs, even if stressed more, will not break, only show more string follow. Then the excessive flex in sal can be reduced by forced (heat) straightening of other sections of limbs.

Adam

alex27 · Post by **alex27** » Sun Dec 09, 2012 8:02 pm

So, working on the core is done, ready for sinew! Hope to start sinewing end of this week.

Thinnest spot is on 2/3 sal, about 8.5 mm
The tips look huge, but will work them down later, also planning a splice in the tips.

The other bow is the magyar bow I was working on, thank you P?ter Bensik for all the information you provide on these bows!

Kviljo · Post by **Kviljo** » Mon Dec 10, 2012 7:27 am

Those look very good from here! It's going to be interesting to see how they turn out bending with sinew!

alex27 · Post by **alex27** » Mon Dec 10, 2012 5:25 pm

Thanks, yes I am looking forward to bend and string them without to many problems, like horn delamination or twist corrections.
I tried to make a magyar some time ago with quite some reflex in the grip, and had a lot of problems bending it on a pegboard. The bow had developed so much twist as well, that I took it apart again. Still have the wood/horn parts of the limbs attached. Am going to try to make a small kind of plains indian bow out of it, have to decide how to join those parts together still.

But I hope these bows will go the way they should go!

Uli · Post by **Uli** » Mon Dec 10, 2012 8:40 pm

sure they will

alex27 · Post by **alex27** » Fri Dec 28, 2012 1:32 pm

Two bows ready for seasoning!