early No. 80 fuze thread

[Alpini]

In the "Notes on Ammunition" 1905 Edition there is a diagram of a very early No. 80 T&P fuze which I think was the first mark. On the following picture I put it into comparsion with a later mark V No. 80 fuze. When comparing the upper left picture with my Krupp fuzes it is clearly visible that this (first?) mark had the original Krupp fuze thread. Later No.80 marks (picture below for example) had the british fuze thread.

My question is if anyone has seen such an early No. 80 fuze with Krupp thread? I wonder if it was really introduced. If yes there must be also a different adapter ring. If it exists a picture would be great.

 

[Gspragge]

The oldest #80s I have seen over here are all dated 1906 which I imagine correspond to the first shipment of 18 Pdrs. to Canada. These fuzes are all aluminum.
I will try to get a picture of one, I think the threads are the finer type. So the change if there were R^L made #80s with the coarse thread was by 1906. But I'm
rather out of my element on this matter.

 

[Darkman]

1906 No. 80

The oldest No. 80 fuze I have is an all aluminium Mk 1 by VS&M dated 9/06. This has the finer BSW (British Standard Whitworth) thread form of 14 TPI. The full markings are: V.S.& M . 80 . 1. 15/C . 9/06. Unfortunately someone has filed the start of the thread down, but the pitch is still easily determined. The early Krupp fuse thread form, although coarser than the Whitworth form, appears to be a Metric fine tread. At this diameter the fine form can have a pitch of 3 or 4mm.

Cheers,

Graeme

 

[Bonnex]

The diagram in the Treatise on Ammunition 1905 does show the course thread but the text refers to 14 TPI. The associated paragraph in Lists of Changes makes it quite clear that the No 80 Mk I was the first fuze to use the new 2-inch x 14 TPI thread. I expect this means that the diagram in the Treatise is made up from earlier Vickers/Krupp drawings; the Vickers design 6684G originally used the Krupp gauge and I expect other threads in the fuze were not to the English standard.

 

[Alpini]

@all: thanks for your answers. So I guess more and more that they did not exist in Service with the coarse thread as on the drawing from the Treatise on Ammunition because the book was published some time before the No.80's went into mass-production.

@Darkman: I have one from 5/1906 with the stamp

E.O.C.
V.M.

restamped in 11/1914 by the RL.

But it also has the 14 TPI BSW tread.