The right limb is already by 1mm thinner but it is still too stiff. Is this common or I used wrong pair of horns ? I hope I will get at least 60 pound bow from this. Left limb is 13mm and right 12.1mm.
Ouch. It could well be that the core is broken right from the grip. Something i have plenty of experience lately…
But don’t lose hope, especially if you did taper the core properly. Maybe horn on the right limb was more reflexed in the grip fade area.
In general, this place should have quite a lot of sinew, since the forces are enormous. This is what i have learned from old bows and other experienced bowyers. Extra sinew never hurts in the grip area.
What does it look like when unbraced? @Matthias is not afraid of broken cores! If sinew backing is good, you will have a shooting bow anyway.
Well you scared me
This is the shape after tillering.
Top limb is weaker.
Yes bottom limb has more reflex in grip/sal area and I’ve tried to reduced it with heat but it didn’t help.
Grip/sal transition on core is triangular and edges are filled with 4-5mm sinew layer.
Unbraced pic looks better. Make it work!
Now I have opposite problem seems like it’s best to make adjustment and then wait for few hours to see change. What was yesterday weaker is today stronger. But It looks better…and it’s so tiny.
Yeah… especially if you have the bow in stressed situation for longer, this happens. Temporary set of some sort. But the bow seems to have enough thickness for 60#. Take into account that after shooting or seasoning the bow for a year you will see the poundage rise about 10#. So 50# bow is easily 60# next year, no joke.
I’m on fulldraw and there is still some imbalance, but it can be corrected or changed by bending one limb over the knee so finally it’s end of scraping.
65 pound at 28.
Very well done! Patience helps. Although there were guys who said you were impatient, hah!
But good bow is a good bow, unstrung profile seems spot on. Limbs will have a little bit of deflex for a while.
Right limb kasan eye is a bit more stiff than on the left. Your bow mass was similar to mine, 110-115cm bow at 60-70# = 350-380g.
I’m interested, did you take precise core measures? Like thickness and width by every 5cm or so?
For hornbows there is these tiny features that i’m starting to see. Meaning, the bow might be perfectly fine without paying any attention to these but… here you can see the soft areas. While left limb kasan eye is soft and right limb grip area is soft, these balance each other out. Although, these will act to effect brace height and string angle differently.
- more kasan eye bend will make string angle “worse”
- more grip bend will make string angle “better”
→ this might make you feel like there is awful lot of bending imbalance, althought there is not.
I don’t know if this is just useless rambling, but anyway… I’ve yet to see perfectly balanced bow. Maybe Björn, Ivar, Francesco, Adam, Alex, Lehner etc. get close to it.
Thanks. I don’t know for sure thickness of the core. Maybe 4mm in mid sal. I measured horn+wood by every 4cm and shaped it to 0.1mm accuracy before sinewing. Width is by eye.
I think I’ll shoot for a while and then maybe go back to tillering. After 6 months or so
This is exactly what i meant. Do you mind sharing the measurements?
I don’t know for sure this is from the head. If I can find the paper, I’ll check it out.
0cm - 33mm
4cm - 20mm Arrow pass
8cm - 14,2mm
14cm - 11,7mm
18cm - 10,8 mm
22cm - 9,8 mm
26cm - 9,2 mm
30cm - 8,8 mm
34cm - 8mm - Kasan eye. From this point it was by eye.
Shot it for the first time today. I’m amazed by the non-existent handshock. But it’s quite slow - 190 fps with 430 grain arrow (7gpp, 20 strands dacron B55).
I think kasans are too heavy, they’re 29mmx16mm in the middle, It should be more like 25x15 for this poundage. So maybe few fps is missing there.
Its the string, as your other topic suggests. Also fresh bow is a bit slower, it needs to age in order to become more snappy.
It’s by 20 fps slower than Adam Karpowicz target bows in 7 grain per pound range.
So 10fps is maybe seasoning and 10fps Adam’s secret.
Edit: I found out that I shoot 27 inch arrow and not 28 Now it’s 200 fps with 7gpp.
Marek - I would like know, in your first two photos, what is that panel called to which the bow is clamped? Would you please describe it a bit and how you use it? Thanks
It’s a peg board. I made it because the bow was too stiff and impossible to string in the beginning. You can use it also for tillering.
You secure one limb and bend the other with both hands. And then the opposite until you reach the bottom of the board.
How thick is it? Made of plywood? Thanks.
It’s made of 3 mdf boards 18mm thick.