Very short bow help please

[stuckinthemud]

I like the 'nothing obviously wrong',  I'm being excessively cautious this time. I understand the 'drawing,' a spreader bar is a really great idea, I think I'll fit one on this set up and see what happens.  Cheers

[stuckinthemud]

not far off brace, tho still on a long string

[stuckinthemud]

Brace height, still on a long string (hanging down 1 inch).  How far past brace do you guys go before you switch to a short string?

[Del the cat]

That doesn't look quite up to brace yet... but to answer the question... just enough to get it comfortably braced.
BTW. Right limb look much thicker, but I'm assuming it's a trick of the light/camera angle tc?
Del

[stuckinthemud]

It is a little thicker, by about 1mm at the point where there is some natural reflex as it seems to be a weak point, I am a bit worried I've reduced the left outer a bit too much though. A short straight edge seems to show a tiny fraction more bend just in from the horn insert.

[stuckinthemud]

Had a really good squint at it across the rim of my coffee mug and I think the right limb is marginally stiffer than the left so I'll  rasp a little off in the morning and see how it looks.  I was going for a 3" brace height and a 6" power stroke, the lath is 27" ntn. Not really too concerned regarding draw weight but it's way strong at the moment, though I have no idea what its draw weight is, not even a ball park figure, any creative ideas how to measure draw weight of somewhere in the region of 150Lb?

[stuckinthemud]

Right, now I'm ticked off with myself and I do not know what to do.
I got the bow to bend evenly and with no set (Yay! first time I managed that)  and to draw to 3" (brace height, but I haven't braced it yet) - no pictures because just as I was about to take one, the bow pulled the winch apart. I put the bow over a bar and pulled my full weight down on it - I weigh about 170#  and the bow bent about 2".  I would like something in the region of 150 at 9" so I figure the bow is about 50# over weight; that's why I'm ticked.

I guess my options are:
1. live with it and build a cranequin
2. reduce width to reduce weight - but the sinew runs right over the sides and down to the belly - does that matter?
3. reduce thickness to improve flexibility
4. reduce width and thickness

so, what would you do?  Are there any other options?  Opinions please

[Del the cat]

I'd remove wood from the belly if necessary.
IMO you really need to get it braced.
I'd suggest making some decent way of fixing it to the wall and use a pulley set up like on my tiller tree. A 220# fishing scale is relative ly cheap.
I've pulled 150# on my set up and I dare say it would take 200#
For actual use in the field a goats foot type lever would do it, as per pictured (bottom right) in this blog post, the bow in the pic is 275# if I recall.
https://bowyersdiary.blogspot.com/2017/06/crossbow-progress.html
This video gives a detailed explanation of the tiller rig and its pulleys to give 2:1 leverage
https://www.youtube.com/watch?v=YGNYlCQk9mU&t=66s
Del

[stuckinthemud]

Thanks Del, that goat's foot might be a game-changer for me.

Found an image taken from not long before I stopped tillering, its bending a 1/2 inch more than this now and the slightly thick section on the right of centre now matches the section on the left. Tillering gizmo shows even and constant bend from the ends of the horn inserts to the fades.

[DC]

5. Make a stronger winch??

[stuckinthemud]

I'll rebuild the winch in better materials with short drums for tillering but I am also looking forward to shooting it where I had hoped to draw by hand, hence a target weight of 150# but a goats foot or wippe will be ok

[Del the cat]

I've just weighed my crossbow (108#). I did a video showing the set up.
Not the best video but it shows how I did it.
https://youtu.be/1JVTiy5BKXk
Del