Questions regarding No. 199 Fuzes

[Alpini]

I have some questions regarding british No.199 time fuzes. It seems that Mk. I to Mk. III had sheet metal caps. I want to machine such a cap. The attached picture shows such a cap and I wonder what the red surrounded "T" is? The second question is about how many of the small screws are holding the cap. Good pictures of these fuzes are also much appreciated

Regards, Alpini

 

[TimG]

Alpini,

The 'T' is to make the fuze readily identifiable as a time fuze.

TimG

 

[Alpini]

Thank you Tim, that was my guess but I did not find something written about it. Is this T a color stamp?

 

[markyakyak]

only one screw holds it on

 

[Alpini]

Hello markyakyak,

I guess your fuze is a more modern type with a aluminium cap. I can read mark IV on your protection caps the fuze may have the same mark. I am looking for info about mark I, mark II or mark III which all had sheet metal caps which are secured with several small screws to a small aluminium ring.

The following picture shows such a '199 Fuze with sheet metal cap. I found it some time ago in the internet but sorry, I cannot remember the source. I hope nobody is complaining about.

 

[Alpini]

Isn't there anybody out there with a No.199 mark I, mark II or mark III? I thought these are very common fuzes?

 

[MINENAZ16]

Hello,

Sorry, only nice pictures of a 199 MkIV.

Regards

 

[TimG]

Alpini,

I stand to be corrected, but I think your diagram is incorrect, notwithstanding it comes from the Textbook of Ammunition 1936. Attached is an official drawing of the No.199 fuze. A major change in design such as changing from a sheet metal to solid cap would normally warrant an entry in the 'Remarks' column.

TimG

 

[Quatermass]

According to the 'Handbook for the 3-INCH 20-CWT' page 181, No. 199 Mark III fuze:

The cap, cone-shaped, is of die cast aluminium, and is screwed to the top of the stem and secured to the body with a set screw.

No mention is made of differences in the cap design in the other marks of fuze.

 

[MINENAZ16]

Hello,

A diagram of No 199 Mark I

 

[Alpini]

@TimG: thanks for your nice diagram, it also shows the sheet metal cap type (on the right side). But this diagram makes things more clear for me. There are three small screws visible but the middle screw has a smaller diameter. My conclusion is, that the middle screw is the set screw and the visible two other screws are securing the cap. I think there are three "screws securing cap" at 120 and the set screw in the middle between two of them. I have one Mk.II which needs a cap and also a Mk.III. Both fuzes had the same few remains of the "securing ring" still visible but only the set-screws and one of the "screws securing cap" did survive so it was not possible for me the see how many screws should be there.

According to Quatermass there must have been a design change during production of Mk.III from sheet metal to solid aluminium cap.

 

[Alpini]

Thanks to the help I got here, I'll show my result as a first prototype of the cap is finished. I hope it is close to the original. A ~6mm hole on the side of the cap for a tool/key is still missing because the weekend was over before a could finish this small last step.

The work started with a old plain piece of 1,3 mm steel sheet metal which I cut into a 1/4 disc shape. This quarter of a disc has a perfect shape which can be bend to a cone. The first photo shows the cap in it's freshly born state. The bending work was done with a hammer anda vice. In the next step I did some TIG welding to close the seam and build a staple cone. The finished cap after the remaining spinning and machining steps is shown on the second photo.

The securing ring was turned from a piece of a 50 mm aluminium rod.