Cap nut on end of pommel - rule of thumb?

[G-Winstead]

I work have a part interest in a brick and mortar knife shop. I can handle most questions about knives, but swords are beyond me. Although just by researching some swords that are brought to me, that I have been able to positively identify and date. And I have seen some generalities that apply to ceremonial / fraternal swords.

So how about cap nuts on the end of pommels, holding the handle/guard on, holding the entire sword together so to speak? I unscrewed one that a customer brought me, purported to be a family heirloom from the civil war, and found it to be a 1/4-20NC. I searched on the net for when the society of engineers decided on this size as a standard, but didn't find out anything. Whatever, I judged it to be a fraternal sword.

So wondering if I can make this cap nut thing a 'rule of thumb'. Are there any iron-clad rules of thumb?

I tried to use the search function here, important when asking a question in any forum, but did not find my answer.

Regards, GM

 

[horseclover]

Please show a picture of the sword, or something similar.

As to sae thread standards, uniform threads probably existed long before being labeled as such and machined threads certainly go back a century or further before that. http://en.wikipedia.org/wiki/United_States_Standard_thread

Here is a Starr sword pommel nut from 1820 but Starr had used the process even before his contract 1812 swords.

I'd love to see the sword being mentioned as a family hierloom, not just because they are often a good bit later than the 1860s. I have a couple of 20th century swords that are also cap screws. The German example does indeed chase with an sae die, as I did so to use a random cutlery nut to replace a missing one. Certainly not so close that it was metric instead.

Random factoid. Seals and bearings are always inch measurements (with metric equivalents given) and spark plug threads are always metric.

Certainly, a threaded method is not universal for all military swords but it was certainly in use with machine threads fairly early compared to the mid 19th century.

Cheers

GC