The early history of the crossbow

[Medicus matt]

Hmmm, I hope the above is clear :

It is and I think it's a stroke of genius which addresses some of my own issues with reconstructions that I've seen so far; well done Robert!

I'd be interested in a reconstruction if you get around to making some.

[Flavivs Aetivs]

Hi Thomas,

Pretty cool drawings!! Why is the recess to hold the bow in the stock that deep? Also 36 cm drawlength does not seem a lot for a bow 90 cm wide.

There is another thing puzzling me. Neither of the two pictures show the bow being fastened with lashings. What are your thoughts on the way the bow was fastened to the stock. Is there an ancient text that descrides such a lashing and does it indeed apply to this type of crossbow.

The haute-loire shows a partly-round, slightly recurve self bow...

I looked at some images of gastraphetes reconstructions and they seem to show the bow inserted through like a hole or something in the stock, and glued in. However I doubt you could do this without breaking the bow.

[Robert]

Hi Matt,

Thanks! :oops: Ohh, I just love (mechanical) problemsolving. I am thinking of building the bow either as an ash selfbow or as a composite (ash with horn backing). The later would certainly add to the punch. I have contacted my friendly local bowmaker who is very interested in such a contraption. The advantage is that the crossbow will have an excellently crafted bow.
Are all nuts found made of bone, by the way? The old tekst does mention several found and being in the BM. But others will have turned up elswhere ... (I hope).

[Flavivs Aetivs]

Units of Ballistarii are mentioned being in the Gallic army and in the Italian army, so its likely there are some in France.

[M. Demetrius]

I'm a little confused, and never said I was smart... :-)
It seems like the pressure of the bow string against the notched part of the nut would press back against the rod. What keeps the rod from just slipping back on its own under the pressure? That looks like it would make for a very dangerous situation. You couldn't, say, lay the cocked crossbow on a table without holding the handle, or it would simply release on its own, and launch the arrow unexpectedly.

Or am I missing something?

[Thomas V.]

I'm a little confused, and never said I was smart... :-)
It seems like the pressure of the bow string against the notched part of the nut would press back against the rod. What keeps the rod from just slipping back on its own under the pressure? That looks like it would make for a very dangerous situation. You couldn't, say, lay the cocked crossbow on a table without holding the handle, or it would simply release on its own, and launch the arrow unexpectedly.

Or am I missing something?

Hello M. Demetrius,

I had the same thought/doubt at first, but now I think that Robert's mechanism would in fact work.

Just take a look at Robert's drawing. The force transmitted by the string would initiate a counterclockwise rotation of the nut. Because of the rotation, the lip of the nut would push the rod back, but as the top side of the rod prevents the front half of the nut's underside from travelling downwards, the nut doesn't move and hence the rod stays in place.

Regards,

Thomas

[Ildar]

Robert,

First, your trigger would be simply pushed back by the rotation of the nut, which would be caused by the bowstring. To hold it in place, you would need another trigger.

Second, similar handles are widely known from the Medieval period. In particular, they were widely used by the Arab crossbows and by later hunting stonebows. The influence of the devices seen on the Gallo-Roman reliefs can be seen clearly in this Moorish crossbow from Granada. Here you can also find depictions of crossbows with similar rear handles, shown on some of the miniatures of Arabic (and other) manuscripts. You can read about stonebows in Ralph Payne-Gallwey.

[attachment=7655]Egon_Harmuth_Die_Armbrust_25.gif[/attachment]
[attachment=7656]Egon_Harmuth_Die_Armbrust_26.gif[/attachment]

Finally, third, all the finds of the three nuts (Buiston Crannog, Southgrove Farm and Carnuntum) and the bone handle (Southgrove Farm), which can be conditionally ascribed to the Roman period, were discovered in the 19th century. Unfortunately, the context and the circumstances of those finds are not entirely clear (even in the case of Max von Groller), and they actually might turn out to belong to the Medieval period. And the handle from Southgrove Farm does not necessarily belong to a crossbow. For example, in the original article of 1894 it was presented as a knife handle.

[attachment=7657]Buiston_Crannog_Ayrshire.jpg[/attachment]
[attachment=7659]Southgrove_Farm_Burbage.jpg[/attachment]
[attachment=7658]Max_von_Groller_Die_Grabungen_in_Carnuntum_1909.jpg[/attachment]

[Robert]

Hi Ildar,

You could very well be right. Although what I suggest is a bar underpinning the nut, so it does not rotate as it is held in place like Thomas describes. If you look at the force vectors, even a lot of pull on the nut will not cause the bolt to force the trigger back. What puzzled me is the iconographic evidence, showing a shaped handle at the rear (for which there is really no obvious function) and very little space for a trigger mechanisme as found in Medieval crossbows. I realise the handle found is thought to be of a dagger, but it is found in context with the crossbow pieces and no remnants of an iron blade are present, linking it to a dagger. The iconography does show a somewhat similar handle.
But is a theory, so I can only prove or disprove it by building a working model, I suppose.

[Flavivs Aetivs]

Thank you for that illdar, but the styling of the pattern on the southgrove crossbow's bone slat decor is similar to patterns found on saxon combs from the 5th and 6th centuries, and can be used to date the southgrove crossbow. Furthermore, the nut would not rotate and push the handle back if you used a flat rod underneath the nut, as it would merely push down on the front of the handle, and the back of the handle would push up on where it is inserted into the stock. The friction force would be greater and the nut would be unable to rotate without it being pulled back.

Also you could use a screw mechanism in the handle to fire the crossbow, but that would be difficult to aim when turning the handle.

[Thomas V.]

Finally, third, all the finds of the three nuts (Buiston Crannog, Southgrove Farm and Carnuntum) and the bone handle (Southgrove Farm), which can be conditionally ascribed to the Roman period, were discovered in the 19th century. Unfortunately, the context and the circumstances of those finds are not entirely clear (even in the case of Max von Groller), and they actually might turn out to belong to the Medieval period. And the handle from Southgrove Farm does not necessarily belong to a crossbow. For example, in the original article of 1894 it was presented as a knife handle.

This article features the three aforementioned nuts (if anybody should be interested): http://ads.ahds.ac.uk/catalogue/adsdata/...17_321.pdf.

[...]showing a shaped handle at the rear (for which there is really no obvious function) [...].

I disagree. If you equiped the arcuballista with an conventional twice bent trigger (like shown by my first drawing), the handle protruding from the rear end would serve as a thumb rest and thus as a counterfort everytime the other four fingers push the trigger up.

[Robert]

Interesting though. The handle would in that case just be an ornamental part of the stock. Could be, I was just trying to make sense of the different pieces found in that grave. You see, I am also searching for a good design and wondering if the Z type handle had always been around as a trigger configuration. My bowmaker, who has made many a medieval crossbow, tells me there is much wear on the revolving nut and it needs replacement after only a limited time of heavy use. Which is why I was looking at a pre-medieval possible design. It does solve quite a few problems early crossbows have, but the lip on the nut makes the design questionable for sure. I do believe it will work fine, actually :-)

[Flavivs Aetivs]

I think the sliding handle idea is much more plausible. It's simpler and easier to replace if the trigger breaks. Cheaper too.

[Thomas V.]

My bowmaker, who has made many a medieval crossbow, tells me there is much wear on the revolving nut and it needs replacement after only a limited time of heavy use. Which is why I was looking at a pre-medieval possible design. It does solve quite a few problems early crossbows have, but the lip on the nut makes the design questionable for sure.

Maybe the thinness of the nut's lip is a consequence of the z-trigger design (abrasion)?

Another thought came into my mind: Would your trigger mechanism even require a lip on the nut?

Regards,

Thomas

[Flavivs Aetivs]

A lip on the nut would add sideways force to allow the handle to slide out without it being done so purposefully. It might be that when the nut was attatched, it was designed with a screw-handle, so you screwed the handle out to fire it to prevent it from being pushed out. A guy in comitatus made one like that back int he 90's.

[Thomas V.]

A lip on the nut would add sideways force to allow the handle to slide out without it being done so purposefully. It might be that when the nut was attatched, it was designed with a screw-handle, so you screwed the handle out to fire it to prevent it from being pushed out. A guy in comitatus made one like that back int he 90's.

Were the Romans even capable of (such precise) threading? Also, wouldn't using a screw-handle as a trigger be to slow and to akward to handle?

Regards,

Thomas