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240's sheep horn bow build with Tom Lucas
NorthHeart:
Big day today. Baby shoots her first arrows...the smaller sheephorn bow that is. I needed a tiller check from a veteran eye and my buddy James Rempp was happy to help. Often as he flexes a bow he tells me it’s a bit stiff here or there. You can imagine my surprise when he says “nice job, let’s shoot it!” I told him to go ahead and be the first! Did you know that after all the research and work I had still never actually shot a horn bow! Well he really enjoyed shooting it and then later this evening I shot it too. So smooth and sweet! There’s still some work to be done here and there, but I am happy to see an unbelievable amount of hours and learning lessons transfer into something that works. Just wow!
Russ:
I know this ended a little bit ago but I never got to say congrats! You built a good bow! good job!
NorthHeart:
--- Quote from: Deerhunter21 on April 22, 2019, 12:22:50 pm ---I know this ended a little bit ago but I never got to say congrats! You built a good bow! good job!
--- End quote ---
Thank you for saying so Deerhunter! But i still have more to go, and the lessons continue.
I haven't seen much info regarding the actual performance of sheep horn bows(fps and such). I plan to do some testing to gain insight on both bows. The short bow was drawing around 39# at around 16", 525gr arrow around 102fps. Certainly wasn't gonna break any records, but i was thankful it was shooting and still in one piece. Wanting to push further, i added another layer of sinew pulling it into more reflex and resulting in what would obviously be a higher pound bow. But keep in mind how narrow the limbs were near the tips. It started tweaking the limb in this area due to the force necessary to brace the bow. Also the string loops were starting to slip down the nocks and actually debraced the bow when i attempted to string it. So i put it back on the form to induce more deflex in the limbs with heat, only this time the sinew lifted from the horn in one area, all the way across:( I don't know if its because i heated it too much, or if i simply exceeded the amount of times that hide glue will allow one to continue making heat corrections. In an attempt to repair this i injected hide glue into the crack with a syringe. I doubt it will be as good of a bond as original but it was about all i could do at this point. Also, this occured in an area where very little flexing occurs, so i still have hope. After all this i wrapped the entire limb with a light layer of sinew to hold things down. The tiller still appears fairly close and this was the lower limb which will be stiffer anyhow. Also i added more sinew to my nocks to keep the string on.
At this point the draw weight is up, and i think i'm still ok on my horn/sinew ratio though its probably close. Now i have some choices to make so that i can brace the bow without the limb tips tweaking from the force. Either heat it again in the form to induce deflex into the limbs which should reduce the distance the tips have to travel to brace. Or possibly build side plates to reinforce the tips and wrap it them with sinew. One thing thats for sure is i keep learning about the horn bows, and thats as important to me as the bows themselves ;)
NorthHeart:
Current profiles.
NorthHeart:
The small sheephorn bow is back with some zip! After separation of the sinew from the back in multiple areas I decided to wrap both limbs with sinew down the entire length. I used heat to re-tiller the bow and get some of the reflex out because the stress was causing the ends to start twisting at brace. I believe I finally found the balance between gaining more power and what the bow can handle without over stressing the limb tips. My old speed was a 525 gr arrow at 102fps. It’s now shooting an average of 137fps. The specs are 45# @ just shy of 18”. Now the question is one of how far it can be drawn safely? I’m sure even more speed and power lie there waiting, tempting me. I remind myself it’s my first sheephorn bow ever, I deviated from original design concepts half way through the build, and made plenty of mistakes along the way. I am elated to see it come this far, and I now consider it a bow.
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