OneGuyFromBarlick

Well done, Ian, a good bit of sleuthing - it was still difficult even with the clues! I took the photo of the Holman Projector anti-aircraft device a couple of weeks ago in the King Edward Mine Museum at Camborne, Cornwall. Since then I hadn't looked it up on the Internet but I'd also taken a photo of a poster in the Museum describing what it was and how it worked. I thought it fascinating and guessed it might be fun on this thread. I liked the story of how the well-known Cornish company, Holman, had done a bit of what we now like to call technology transfer - they knew a lot about mining equipment running off compressed air and decided they could do something to help the war effort (as well as making themselves a few bob!). In my second photo the man with his arm in a sling is Treve Holman and I guess it's the same man in the pic on the wiki page that you linked (and which provides a lot more information). Below is the poster seen in the Museum (click for a larger version).

Lovely subject! There are two books.... The Secret War by Brian Johnson and Secret Weapons of WW2 by Gerald Pawle, both on Bookfinder for peanuts. Well worth reading as there were dozens of fantastic ideas which were built and tried out.

Thanks, everyone, for your efforts to identify the Holman Projector, and I enjoyed the Churchill story in Ian's Wikipedia link. For anyone who didn't read it, Holman's were asked by the army to demonstrate their Mk.1 version for Churchill to get his approval. Holman's turned up with the device but the army forgot to bring the grenades for it to fire. The group had met out in the countryside for the demo and had food and drink with them so somebody suggesting they might be able to substitute bottles of beer for the grenades. They tried it and found they could hit the target and the bottles burst with a bang and a cloud of froth! And Churchill gave his approval, even if he had to give up his beer!

A small footnote. Holman's were turning out large numbers of compressed air driven rock drills for the export trade to mines which is why they had the expertise for designing the device and the equipment to make it. But I think there was another advantage. The rock drills are too heavy to hold and so the usual set up was to attach it to a support. This consisted of a length of metal pipe placed vertically and attached at the bottom to the mine shaft floor and above to the shaft roof. Now, I'll bet that if you measure the internal diameter of one of those supports you'll find it's the same as that of the projector barrel. They must have had a lot of that pipe!

Clive Carter's book 'Cornish Engineering' is a good history of Holman's. Barton's 'The Cornish Beam Engine' has lots of references as well.
Try this one....

A chain 'whip', for wrapping round a pipe to manipulate it when drilling for treacle.

Its a lump of bike chain with another piece of metal fastened to the end..........

Sorry, no to both. Clue, chain is used for things other than bicycles. This one is bronze.....

David Whipp wrote:A chain 'whip', for wrapping round a pipe to manipulate it when drilling for treacle.

Love it!

Part of a tool but don't know what the tool is called, is it called a chain wrench for pipes and oil filters and that sort of thing?
Bronze is used in flammable environments when you want no sparks, like on oil tankers.

chinatyke wrote:Bronze is used in flammable environments when you want no sparks, like on oil tankers.

...or when drilling for treacle...

David Whipp wrote:

chinatyke wrote:Bronze is used in flammable environments when you want no sparks, like on oil tankers.

...or when drilling for treacle...

There should be a treacle involvement.

Yes.

If it's not used for treacle drilling, perhaps it's used for removing the tops of industrial sized treacle tins?

Or even bomb disposal where magnetic tools are a no no. So there you have it. Removing an unexploded bomb from a methane gas treacle mine situation.

All very inventive but wrong! Clue, it was originally fitted on Liberty ship which sank off the Isle of Skye.

So they were trying for treacle off shore, even in those days?

Was the gadget part of a vertical triple expansion compound engine?

David Whipp wrote:So they were trying for treacle off shore, even in those days?

Was the gadget part of a vertical triple expansion compound engine?

Sounds like Stanley baiting to me.....

Wouln't happen to be part of a hazardous space (magazine - ammunition storage) lightswitch ?. Warships had some bizarre solutions to keeping electrical switches out of magazines.

Liberty ships weren't warships in the established sense but they almost certainly had ammunition aboard.

The ammunition angle could be a serious runner (and alluded to by Plaques in a previous posting).

I think a Liberty ship went down somewhere off the south coast with 1,500 tons of explosives on board. There was also a tragedy which killed hundreds of people when a Liberty ship was being loaded with 2,000 tons of explosives (in Chicago?).

A light-switch though? (My lateral thinking struggling with Heath Robinson arrangements for illumination.)

Pussers warships had light switches outside the dangerous compartment because they had a habit of sparking. There were numerous mechanical arrangemnets so the lights could be turned on from inside the compartment, usually involving bronze.

Remembering what Stanley said in a previous comment about liberty ships. Quote." but a mate of mine bought one which sank off Dunvegan, Skye and salvaged the non-ferrous bits. It was quite amazing how much bronze he brought up. The propellers were bronze but even the ships railings were bronze as well. They didn't have any frills but were strong well built ships."
I'll go for the chord (pun) that blew the whistle!!

Well done P! What a good memory! Not right but close enough. It is part of the bronze chain which, running through a tube, connected the bridge telegraph to the engine room repeater. No fly by wire in those days! Try this one....

Akin to a glass cutter, but not one; for making fancy cuts in leather?

Sorry, no.

Cowboy boot spur?

This one is too hard, it took me years to find out what it was. Here's another pic that gives clues so you can go sleuthing.... (click to enlarge)

Vintage deburring tool?

No, more interesting than that. Think wire......