Colletiere a Charavine crossbow

[stuckinthemud]

There is, in France, a lake called Lac du Paladru which has several flooded sites that have been excavated by various archaeologists. Their finds include several crossbow fragments dated to 1040AD. The earliest known European crossbow remains by several centuries.

These are the only drawings

 

[stuckinthemud]

Making the tiller (stock) should have been easy but the archaeologists drawings were misleading in that they added modern, Asian, round triggers as an illustration of a point in-text but as soon as the text and image became separated the point was lost and the drawing became misleading. The trigger should be a simple straight or slightly curved lever.

I eventually found the original French text and This allowed the drawing to be enlarged to the correct dimensions, which in turn gave the width of the bridle, and thereby the width of the lath. The text also identified timbers used for the various bow fragments found, including ulnus (elm).

 

[stuckinthemud]

Now I knew the timber, the shape and thickness of the tips and the width of the lath at centre and the draw length. Unfortunately no-one knows the important bit- the length overall.

My first attempt was, well, let’s call it a learning experience. Too short and too knotty, it nearly worked and was over 100lb at one point, but the lath failed at a row of pin knots.

My second attempt was slightly longer, from a near perfect wych elm stave. The thickness at the end of the bending section was 11mm as per the drawing and this limited the strength of the bow. I should have got 70lb from it at least but messed things up a little to finish at 50lb. I did answer a few questions, such as how to make the recurve tip and why they were that shape. And a possible length for the stave

 

[stuckinthemud]

I am more and more convinced the original may well have been sinewed.

 

[Adam W.]

That's a nice research project with some good results.

 

[Orraloon]

You got there in the end. Like you suspect it may well have been backed with sinew. The later Germanic crossbows were heavily sinewed. There are lots of other backings as well although they simply prevent the back of the bow splitting. Rawhide was used and various natural fibers. I have had success with gluing on a backing of silk cloth although perhaps not authentic to your project. As you have found what the archaeologists speculate does not always end up as a practical build plan. The English long bow was only fully understood when people got stuck in and built some after the Mary Rose finds. Anyhow great work you are doing and thanks for posting it.
Regards
John

 

[stuckinthemud]

The archaeologists suggested it was a child’s bow and that irritated me no end, but in fairness, in 1981 there was no internet and the museum of anthropology they consulted was worse than useless. I think currently most agree it’s a light bow but no-one I know of had reconstructed a bow from the tip back so the light weight I ended up with is a surprise. Unfortunately that means I need to do another to check my findings. Weirdly, at 70lb it would be a very light bow suitable for a youth to learn on, and that lines up with the original theory.

 

[stuckinthemud]

So, I more or less perfected this into the bin. I wasn’t really happy with its shape at full draw and ended up with 41lb, then I sinewed it and re-tillered, ending up back at 41lb. Thing is performance improved by about 25percent for no increase in draw weight. One day I’ll put another couple of layers of sinew on, but I’ve used all my current stock. The bow feels so much more lively as the sinew compensates for the heavy tips, I’m more and more convinced the original was sinewed

 

[Orraloon]

Good to see you are still at it. Thats the thing about making bows, we basically just have to learn by our mistakes. Of all the branches of woodworking I have tried it had the highest failure rate but something about seeing that arrow on its way keeps you coming back for another crack at it.
Regards
John

 

[clogs]

Mr S in the mud.....
how do u treat the sinewes.......guess they come from a slaughter house....bovine.....?
are they beaten flat or used in multiples.....sit in grooves.....?
very interesting subject

 

[stuckinthemud]

I use bovine blackstrap (also called paddy whack in the UK) because I have to. It is phenomenally greasy. It takes a lot of effort to clean. Deer sinew is much less effort to process. You need to find a butcher who breaks down whole carcasses as blackstrap from a joint is too short. Silver skin above the ribs is a good source of sinew, but because the hooves are cut off at the ankles, leg sinew is useless.
Once thoroughly clean and degreased, put them somewhere warm, like behind a freezer, to dry out - they go amber in colour. Now, bash them with a hammer/mallet/?? to separate the major sinew bundles, then pull them apart to get fine sinew fibres as long as possible. Even 4 inch lengths are useful.

 

[stuckinthemud]

The processed sinew will keep for years if you keep it dry and away from pests. To use it, sort into bundles which you soak in cool water, then soak in hide or gelatine glue then apply in overlapping lengths to a surface you have already sized