No 80 T&P fuzes: markings and unknown adapter ring

[Rod Burgess]

All wisdom gratefully received on two No 80 T&P fuzes, one of which has some kind of adapter collar. I've not had a great deal of luck trying to photograph them so I've attached drawings. Both are verified inert by a modern ammunition expert.

 

 

Item 2

Stamp-marked on the base as a No 80, Mk VI and dated "2/18". I can find no maker's mark, though there is a blank circle, 3.5mm dia, at 2 o'clock which appears to be caked with the original waterproofing varnish - could that be an illegible trademark? The Lot No is 115. There's a tiny "F24" or possibly "F21" just below 3 o'clock and between that and the circle is a finely engraved radial datum line with two extremely small circles or zeros adjacent. At 4 o'clock there's a small circle or zero and at 5 o'clock a tiny "2". At 10 o'clock is a WD arrow and just above that, between it and the date is a deeper, clearer radial datum line, exactly coinciding with the position of the fuze setting stud.

All the innards of the fuze are missing, as are the cover plates for the gas-escape holes. The nose cap unscrews and can be removed but the two time rings are seized solid with visible remnants of the waterproofing mixture in the cracks. What's the best way of freeing them up? Is it simply a case of judicial application of tiny amounts of WD40 and lots of waiting or is that sacrilege which will do more harm than good? Should I just leave well alone?

Item 1 is more of a mystery to me.

It looks to me like another No 80 but there is no such marking on the base. The stampings on the fuze base itself are difficult to read, being caked with varnish. They consist of:

Large letters " B M O" (or possibly " B M C"),

 

The numbers "3  7     178",

A clear radial datum line,   and

A distinctive, scalloped shield containing a letter "H".

 

Inside the fuze is what looks like the empty graze percussion holder. The standard 2" base thread is screwed into an adapter ring which has an external thread of 2 7/16" dia. The adapter has a set screw hole, plugged solid with waterproofing compound. On its rim it has stampings as follows:

 

"53" enclosed in a circle

A Canadian "arrow in a C"

An identical "53" in a circle.

 

All parts of fuze No 1 are seized solid, including the adapter ring.

 

The markings on Item 1 and its adapter have me stumped, as does the absence of a maker's mark on Item 2. Does anybody have any ideas? And what is that adapter? It's clearly not the fuze-hole bush from a 13- or 18-Pdr. The Treatise states that the largest actual fuze thread size on any British fuze was 2" and that the No 80 is used only on BL 2.75-in, QF 13-& 18-Pdr and the naval QF 4-in Mk IV, none of which seem to fit the bill.

 

I await words from the wise.

[14276265]

The adapter is the 2.5" to 2"-fuze gauge adapter, also known as the fuze socket or fuze bush. If you look up the 1915 Treatise on Ammunition, you'll find it in there.

[Rod Burgess]

That's just my problem, 265 - I'm sure it isn't the fuze bush. The fuze bush illustrated in the Treatise and in Len Trawin's book has a closed base with a central hole which mates with shell's central flash tube and is described explicitly as fitting and being soldered to the central tube. The other fuze ("Item 2") I unscrewed myself from the bush fitted to a sectioned 18-Pdr shrapnel round, and that bush is exactly as described and illustrated in the Treatise and Trewin (photo below).

 

The adapter in question (on "Item 1") is completely different, with a full-diameter open base. The ring you can see in the photo of it below, with the lettering, is the 2" standard-gauge base of the fuze itself, visible through the open base of the adapter. The small hole in the centre appears to be the percussion apparatus holder without its base fittings: it is categorically part of the fuze and not of the adapter.

 

I'm wondering if the "adapter" shouldn't be attached to this fuze at all.

[AOK4]

Hello, The central disc with the hole usually flies off at detonation. Believe me, I've found dozens of them and seen plenty more.

[Rod Burgess]

Ah. That surprises me because it's shown by the Treatise and in Trawin as an integral part of the fuze-hole bush, which is made from a single piece of metal. The bush illustrated is a single component, too and matches the drawings exactly. There is no sign of a fracture in the adapter where a part of it has separated. You're not referring to the "steel disc" which covers the tin cup holding the bursting charge are you (the one with the threaded hole to receive the bottom of the central tube)?

This adapter is solid brass, with no sign of damage and an external thread much less deep than is shown for the fuze bush in the drawings in the Treatise or Trawin and certainly, less deep than the one on the nearly pristine bush shown in my photo above. Nor is the internal contour of the bottom of the adapter the same as the one in the illustrated fuze-hole bush. Nor does its external contour match the curve of the nose of the No 80 fuze fitted to it: there is a distinct "step" and the slope is steeper, as if designed to match a shorter, blunter fuze.

I am absolutely convinced that this is not the fuze-hole bush from a QF 18-Pdr shrapnel shell, neither do I think it's one from a QF 13-Pdr or a 4.5-in howitzer, though I don't have an original of either to look at.

[AOK4]

I am absolutely certain about what I said. I'll check in my shed tomorrow whether I have somewhere the relevant pieces and take a pic to make it clear.

 

Jan

[Rod Burgess]

Aaah! The shed - repository of all that's wonderful.

[AOK4]

Three pictures to explain things a bit. Pic 1 shows these "discs" that usually come off from the adapter ring in the explosion. They can be found a lot on the fields. Pic 2 and 3 show how these fuzes are usually found. On the left is the more common way of finding them, including the adapter ring but without the "disc", on the right with the "disc".

 

[Rod Burgess]

Thank you for those photos, AOK4. The one on the left, without the disc, does indeed look a lot like what we’ve got here, though your fuze base seems to be screwed further into the bush, nearly reaching the bottom, as shown in Trawin and the 1915 Treatise.

I’m still surprised that, if the base disc was ripped out of the bush by the action of the bursting charge pushing everything forward, there is no sign of traumatic fracture of the metal at the edges of the disc or the inner edges of the fuze hole bush “skirt”. The sources all show the bush as a single component drawn, turned and threaded from a single lump of “gunmetal”, rather than as an assembly of separate components. The one we have, actually fitted to A Mk III 18-Pdr shrapnel shell, and this one in the Canadian War Museum both look exactly like the drawings in Trawin and the Treatise.

Conversely, the outer profile of our “adapter” and its inner profile where the inner wall meets the base disc seem different from the fuze hole bushes in the sources, in the photo and in the Mk III shell in our possession. Do you think its possible that the “adapter” we have here, seized onto the base of the No 80, is actually from something other than an 18-Pdr shell and should not really have a No 80 attached?

Do you have any idea what the stampings on the fuze and the “adapter” indicate? The ones on the fuze don’t seem to conform to the spec in the Treatise or those in the 1918 Explanatory List of Service Markings.

 

[AOK4]

There is nothing special about your adapter in my opinion. I have only very rarely seen a slightly different adapter for No 80 fuzes, which extends a little bit further below the thread but yours looks completely normal.

[Rod Burgess]

OK. That's it, then: it's a standard fuze-hole bush for an 18-Pdr Mk III shrapnel shell with a No 80 fuze screwed into its 2" internal threaded socket. Many thanks for your help.

[14276265]

1 hour ago, AOK4 said:

There is nothing special about your adapter in my opinion. I have only very rarely seen a slightly different adapter for No 80 fuzes, which extends a little bit further below the thread but yours looks completely normal.

 

 Agreed.

[ServiceRumDiluted]

Heres one that somehow remained intact

[Rod Burgess]

Yes, that's just pretty much identical to the intact one we've got in the sectioned shrapnel shell for the other fuze ("Item 2")