Shenkl Fuze Thread Question

[callicles]

Kinda silent here; thought I'd post a question.  I normally bug Pete with a million questions; so I thought I'd give him a break and ask it here:

On a Shenkl percussion fuze (brass, Pat. D. 1861) you find 9 or 10 threads.  They are obvious, big, and easy to see.  But, below the big threads, down the "shaft" which looks to be a smooth brass surface, there appears to be very fine, hair-line threads. I have seen the same thing on some Hotchkiss fuzes.  Can anyone tell me what the use was for such a finely threaded shaft? They seem so miniscule, and so finely cut as to serve no purpose.  However, I know that can't be the case.

Thoughts appreciated.

Thanks

 

[John D. Bartleson Jr.]

They serve no purpose.  More than likely caused by the thread die or the lathe tool if cut on a lathe.  I am not certain as to how the body threads are cut - die or lathe tool.
Regards,
John

[Selma Brooke Gunner]

I have to agree with John on this.

[joevann]

Absolutely.  In this time mass production would have been done on a lathe.  The marks a the run out after reaching the end of the casting where the threads are supposed to be.  The single-edged cutter travels an a geared setting.  They serve no purpose, just a tool mark blemish.

[callicles]

Thanks to all who responded.  I learn something every day!!