Primitive Archer

Main Discussion Area => Bows => Topic started by: Del the cat on November 10, 2017, 07:59:27 am

Title: Friday Weirdness!
Post by: Del the cat on November 10, 2017, 07:59:27 am
I'm experimenting with making a shoot through crossbow prod that can flex along it's whole length.
So far it's made of bamboo strips glued up edgewise so that I can get the curves then a belly slat of Hickory.
Next step will be a Yew belly, or whatever takes my fancy, or I may do some initial tests on it.
It's been done very rough and ready, and a final version could be glued up with some deflex/reflex.
I thought it might raise a smile!
Any suggestions, sensible, daft or humorous gratefully received :)
Del
Title: Re: Friday Weirdness!
Post by: FilipT on November 10, 2017, 08:13:17 am
I never understood how string of crossbow sits in relation to the arrow groove. Does "bow" have some kind of angle related to the groove so the string has minimal friction when the arrow is released? I Because of that, I too thought of shoot through bow and I am interested how it will your experiment turn out to be.
Title: Re: Friday Weirdness!
Post by: stuckinthemud on November 10, 2017, 08:21:59 am
If you use side nocks cut into the bottom edge of the prod, you can arrange it so that the string is level with the top edge of the bow, then you fit the prod into the bow at an angle (I think of 5 degrees?) so the string slides easily along the top of the bow.

Del, I got nothing, but I will be watching with interest.  Presumably the centre-hole is not a snug fit on the bolt to allow for it ovalling as the prod bends?
Title: Re: Friday Weirdness!
Post by: Del the cat on November 10, 2017, 08:28:16 am
Hi, yes, the old style was to have the bow mounted below the track and it would be angled with the tips lifted to minimise friction. The better modern crossbows have individual limbs mounted high with their centre-line in line with the top of the track so they are effectively shoot through. The problem with individually mounted limbs is, if you are using natural materials is that yous loose a lot of working limb and have to compensate with a longer bow or a shorter draw.
The bow mounting for a bendy shoot through should be relatively simple as it just needs to be bound in place, probably with leather between the support and the bow and maybe bound on with 1/4" square rubber strapping. Trying to clamp individual limbs solidly adds a lot of stress at the clamp/mounting point.
I've been experimenting over the last few months trying to get a reliable crossbow of over 200 fps with commercial weight bolt from natural materials. I've had 240fps but only with V light bolts.
It's all just a bit of fun and a change from the usual stuff
Del
Title: Re: Friday Weirdness!
Post by: Del the cat on November 10, 2017, 08:33:42 am
@ Stuckinthemud.
Yeah, I've done all the usual prod mounting arrangements, just trying to think outside the box and do something a bit different (doubtless been done before, prob' by the flight guys!).
The hole should be plenty big enough. I had JW ship it over from the States  ::) and the US sizes are bigger ;)
There will be a bit of thickening in the centre to allow for chaffing where it mounts, but it will still flex a tad.
This is just a quick look-see prototype to find out if it's worth doing a decent version.
It was fun jigging up and gluing the boo strips (in a sort of masochistic way)
Del
Title: Re: Friday Weirdness!
Post by: stuckinthemud on November 10, 2017, 08:37:41 am
now the weather's turning colder, its nice to have a project you can do by the kitchen table  >:D probably more fun than match-stick models or jig-saw puzzles.
Title: Re: Friday Weirdness!
Post by: DC on November 10, 2017, 10:54:54 am
I thought ship able holes were always black ;)
Title: Re: Friday Weirdness!
Post by: Hawkdancer on November 10, 2017, 11:14:10 am
Only those not shipped by JW!  He is in the Black Hills, not black holes!  Must be something in the air up there that causes the color change 8) >:D!  Interesting build, I am curious as to how the prod is secured so the thing doesn't fall apart when you shoot a bolt!  I should get a CB to use as a prop in my Hunter Education classes.
Hawkdancer
Title: Re: Friday Weirdness!
Post by: willie on November 10, 2017, 11:36:25 am
Did you mean to say hickory backed and  yew bellied?
A box beamed composite bow has always been an interesting concept to me,so will be watching your experiment closely,
what GPP will a natural matl. bolt work out to? (sorry, I am not very knowledgeable about crossbows)
just guessing, but are you going to make it a bit wider around the hole?
Title: Re: Friday Weirdness!
Post by: Del the cat on November 10, 2017, 11:41:48 am
Did you mean to say hickory backed and  yew bellied?
A box beamed composite bow has always been an interesting concept to me,so will be watching your experiment closely,
what GPP will a natural matl. bolt work out to? (sorry, I am not very knowledgeable about crossbows)
just guessing, but are you going to make it a bit wider around the hole?
It will be a Boo, Hickory, Yew sandwich... with maybe a little peanut butter  :)
Del
Title: Re: Friday Weirdness!
Post by: bubby on November 10, 2017, 12:01:06 pm
There is a guy building hornbows with a split limb design, beaumont vance on facebook, so i am sure this will work
Title: Re: Friday Weirdness!
Post by: Del the cat on November 10, 2017, 12:54:12 pm
There is a guy building hornbows with a split limb design, beaumont vance on facebook, so i am sure this will work
Just had a look, very organic funky looking bows :)
Del
Title: Re: Friday Weirdness!
Post by: Marc St Louis on November 10, 2017, 03:15:08 pm
I made s shoot through crossbow years ago, wrote an article for PA on it.  Can't seem to find any pictures of it right now but the prod was a sinew backed HHB with slight recurves and which pulled just over 100#.  It would shoot a 500 grain arrow around 175 fps if I remember right
Title: Re: Friday Weirdness!
Post by: JW_Halverson on November 10, 2017, 05:07:02 pm
Only those not shipped by JW!  He is in the Black Hills, not black holes!  Must be something in the air up there that causes the color change 8) >:D!  Interesting build, I am curious as to how the prod is secured so the thing doesn't fall apart when you shoot a bolt!  I should get a CB to use as a prop in my Hunter Education classes.
Hawkdancer

Years ago I bought a dry oil well at a bankruptcy auction.  I pulled the hole out of the ground and sawed it into manageable lengths and have been selling it as "pre-dug post holes".  You just load them in the back of the truck and drive along with a kid in the back dropping one in the ground every so often. A second guy comes along dropping the post in the pre-dug post hole. Slick, huh?  I cut some extra small and washed them in hot water to shrink so Del could put pre-drilled knot holes in his bow limbs.
Title: Re: Friday Weirdness!
Post by: Hawkdancer on November 10, 2017, 05:23:44 pm
And pours hot water in to shrink the hole to secure the post?  Saves work tamping!!  Wow!!
Hawkdancer
Title: Re: Friday Weirdness!
Post by: stuckinthemud on November 10, 2017, 05:54:03 pm
Hmmm, I'm forever locking myself out.... >:D