Steel split limb crossbow

Since becoming interested in crossbows again,I have looked at many different types of homebuilds,some crude but workable,some of an incredibly high standard,almost works of art.At the present moment,I am modifying an old crossbow that has a steel prod,using it as a test bed for ideas.
                 I would like to make it a split prod design,but o all the split prod designs I have seen,the prod has been either laminate,or solid glass,no steel split prod designs.
                                       As I know there are some highly skilled and extremely knowledgeable builders in the guild,I would like to ask why no-one seems to have pursued this design,or if they have,why they did'nt choose to use it again.Thinking about it,I can see no reason why such a design would'nt work,but never having built a split limb bow,I lack the practical experience to know,I look forward to your comments,and any experience you have had with such a bow,either commercial,or home built.

Why make it split? Is the bowstring bearing down on the tiller top?

My slide bows make mounting a single bow too low to be practical. You should be able to mount a steel bow high enough and at an angle where the string has minimal friction in its power stroke. If its a wood tiller you could carve the tiller out to reduce friction.

I don't know about splitting the steel limb. I only work with composite bows. Maybe geezer will drop in. I can however tell you that changing any bow to a split limb setup is no small task. You might as well just build a whole new bow. Riser design is not simple. Limb alignment and clamping are very difficult.

The initial crossbow had a setup I really did'nt like.Instead of the normal mortice thru' which the bow was inserted,there was a slot.The bow was held in place by a hooked rod that went down thru' the stock with a nut on the bottom.The crossbow itself is fairly old,has a stock of maple(which leads me to believe it was made in North America)and no manufacturer's identifying marks.There is a thin steel plate either side of the stock,held in place by 2 threaded rods with a blind nut on each end.I felt that the slot weakened the stock unnescesarily,and had to go.
                                                                      With regard to the split bow,this idea I like,as it has to be better than tilting the bow,much less friction,and reduced string wear.As I said in the first post,I am using this crossbow as a test bed,when I am happy that it incorporates what I want,then I will build the bow that will be my actual hunting bow,with the draw weight I want,and have the features I need,this one will be the prototype.
                                                                       No point getting older if you don't get wiser.Obtaining info from the people who invented the wheel,means that I save time,materials and effort by not having to re-invent it,and,like tinker,I'm not proud,and will profit from others mistakes(we all make em sometimes),and will cheerfully steal anyone's ideas,what's more,I'll even give them the credit!.
                           Where I live,a weapon is a tool,something that it's foolish to be without.Like most people,I need a reliable tool that is the best available,and will do the job required of it.I have sufficient experience of working wood and metal,that I can handle the engineering for a split limbed bow,but I have'nt actually done it,so I'm looking to profit from anyone who has,or has owned such a metal limbed bow,as while it is do-able,there may be reasons why it is better not to do it,hence the inquiry.

I am a believer in the old saying........."measure twice,cut once".

Yeah, it's definitely interesting, I have never seen a steel split limb.

Hermit:  The crossbow you started with is almost certainly an old Wham-O or later Crossman "Powermaster"  The Wham-Os used a 31 inch aluminum-alloy prod @ 80 lb. draw with 11 inch power-stroke.  The prod went in a slot cut in the top of the stock, held in place by a hook, threaded on bottom to take a wing-nut.  Most of the later Wham-Os had a steel-shrouded lock, with automatic safety and simple flat peep rear-sight.  Front sight, when mounted, was a gallows suspended from one side.  Later Crossman Powermasters sometimes used a 90 lb. steel bow in place of the aluminum-alloy one.  At some point in their run, Wham-O had a recall for defective trigger-sears... apparently they would sometimes release when the safety was disengaged.  If you're going to keep the old lock, it might be worthwhile to disassemble and examine for excessive wear.  I don't know how much weight it will stand over 100 lb.
Most of the WhamO Powermasters I've seen had oak stocks, but most manufacturers end up using what they can get, within limits.  Some very early models had a notch/pushpin release, without a string-snubber or bolt-clamp. 

Still it's nice to hear some of the old Powermasters are soldiering on.
Hope that helps.  Geezer

Any advice about splitting the bow geezer?

Splitting the bow?  I've broken a few but never deliberately split one.  If I had it to do, I would send it to my friends at Darkwood Armory... they've got a hydro-cutter that would do a dandy job.  Geezer.

split bow work very well it suppress limbs torsion and lot less friction. Building the support is a bit tricky . Here a modern bullet crossbow with the very classic 150# fibreglass limb cut by two.

;;

Wow...that looks dangerous. You'd never get me to shoot it.

I don't know, it looks like it is strongly built to me. Though I probably would wear some protective gear the first few shots. 

Did you make that Jeep?

Todd

Yes I did. I take the inspiration from the very interesting book of Richard Middleton "Man Powered bullets" . The main problem is to be certain that the ball go by the centre and not hitting the side . It is tricky, it depend of the rope and the ball pocket, the limbs balance etc...  Mine work pretty well and very powerful but shooting completely erratic. It need a very long adjustment . I haven't the patience for this. I build it in 2005 still there in a corner of the shop I my go back to work it some day. But I find my last slurbow more simple, more accurate and more powerfull.  

 

;;

I like the cocking mechanism but it looks like a ricochet is too easy.

Wow, that's nifty. How's it shoot?

I have no idea of it performance, I find the picture in the net. The limbs look to be aluminium. Anybody know anything about it?  it don't look very functional, the string is under the surface of the crossbow,so this part is to short and the limbs are to low and there is probably a lot of friction. But the design is fantastic !