Nuts and bolts

[jkaler48]

There seems to be a few hints that threaded nuts and bolts were known to the Legions.
I found a reference that said there was a 1 1/2" square nut found at a Roman military site in the Provincial Museum in Bonn. Germany. Also supposedly Vitruvius mentions a bolt in connection with a crane. The book Ancient Carpenters' Tools by Henry C. Mercer is said to have photos of Roman bolts. (I have ordered a copy)
Anyone have any additional information and/or photos?

[M. Demetrius]

John, I saw a photo of a square nut about the size you mention. I was fairly amazed, and simultaneously wondered why they didn't use them more often, but then, it's hard to know things like that with such small tastes of evidence, isn't it?

[Sean Manning]

John, I saw a photo of a square nut about the size you mention. I was fairly amazed, and simultaneously wondered why they didn't use them more often, but then, it's hard to know things like that with such small tastes of evidence, isn't it?

I think its because the screw threads had to be cut by hand, so anything with them was slow and expensive to make. In later history, the first machines to cut screw threads were invented at the end of the 18th century. Mind you, I don't know anything about how Roman screws were made.

[Eleatic Guest]

Heron's Screwcutter
A. G. Drachmann
The Journal of Hellenic Studies, Vol. 56, Part 1. (1936), pp. 72-77

[jkaler48]

I suspect use was limited to high value items that required frequent dis-assembly and reassembly such as small cranes, Artillery and maybe high end shield bosses that would be damaged by repeated riveting.

[Tarbicus]

Heron's Screwcutter
A. G. Drachmann
The Journal of Hellenic Studies, Vol. 56, Part 1. (1936), pp. 72-77

Here it is:
http://www.jstor.org/pss/626037

Is it really "ancient" or just very old?

See what I mean from Ancient Carpenter's Tools (go to page 253)
http://books.google.co.uk/books?id=_Ssj ... q=&f=false

[P. Clodius Secundus]

I suspect use was limited to high value items that required frequent dis-assembly and reassembly such as small cranes, Artillery and maybe high end shield bosses that would be damaged by repeated riveting.

I know they used screw threads on olive and wine presses, but he only evidence of their use on artillery I can recall is what appears to be threaded screw jacks on the De Rebus Bellicus illustrations. I suspect that ancient woodworkers shared the feeling of their modern counterparts, that the use of hardware is a poor subtitute for good joinery. I've seen the base for a ten foot tall ballista made with only mortise and tenon joints and not a single metal fastener. It could be assembled and broken down for transport using only a wooden mallet. Auxarcher is building a base for a Vitruvian scorpio without any bolts or screws. My carroballista base doesn't need any either. That only leaves the onager and I'll quote from the source on that...."and the beams are connected as in a frame saw, having quite large holes bored in each side; between these beams, through the holes powerful ropes are stretched, preventing the structure from falling apart." Apparently Marsden and Rihll both disagreed with Ammianus on that issue. Most reconstructions I've seen use bolts or some other hardware to hold the frame together. I've got a small scale onager beside my desk that proves Ammianus right. I'll have keep my eyes out for any other evidence of the use of screws.

[jvrjenivs]

I suspect use was limited to high value items that required frequent dis-assembly and reassembly such as small cranes, Artillery and maybe high end shield bosses that would be damaged by repeated riveting.

and to go on to the shield bosses. First, we again need to consider the use of these (but we don't have to repeat that discussion again here) but even then we know of some bosses that had the rivets split on the back and folded to the sides, and if I'm right even examples of a boss with a rivet with a hole in it, so it can be secured with another pin on the back of the shield board. Both perfect ways of attaching a removable umbo, with sources.