Block, Strap, Gib and Cotter

At the beginning of the 2nd WW, my father, a young and newly qualified Toolmaker & Fitter left Archdale's Engineering Works in Worcester to join the Royal Navy. The entrance practical exam at Portsmouth Dockyard for Engine Room Artificers included making a Block, Strap, Gib and Cotter in 42 hrs using only a hammer, chisel and 3 files using no machinery except for drilling holes. I've attached a photo I've found of this type of test piece.

My questions are: what are, or were, Block, Strap, Gib and Cotter and what were they used for. And why were they used to test entrants to the Royal Navy at the start of the 2nd World War?

I would guess those would be used for tensioning standing (steel wire) rigging.

Similar arrangements used to be used to adjust bearings.

Neil

I remember reading a biography of Geoffrey de Havilland who was a Cranwell apprentice I think, and apparently thay has a test of making a mating nut and bolt using only cold chisel hammer and files. I suppose it might just be possible... I suppose that you'd have to make a tap for the internal thread.

They're used to connect rods together that are only subject to axial forces. Normally a block is made on the end of one rod and the strap on the other.

The rod and strap are both traversed by a slot. To assemble the fastener, the block and strap are aligned and the 'u' shaped gib inserted so that it's ends lock on the strap. Finally the wedge shaped gib is hammered into the remaining gap to lock the whole together.

The advantage is that the joint can be assembled and dismantled quickly whilst keeping the parts in the same relative position. Once common on locomotives to connect rods to cross-heads and elsewhere to fix rods to stationary parts.

Your picture (which I've decluttered) is the first I've seen with screw-threads. Possibly this is because they are apprentice pieces rather than the real thing.

My dad joined the RN to train as an Artificer at the end of 1945. He never mentioned any practical exams on entry. Possibly the RN dropped the 'make it with a chisel' test because WW2 didn't have time to waste when most warships were fitted with turbines or diesels. Possibly because it was moved down the curriculum. (Dad was invalided out after a year due to a rugby injury. Near miss for me - that's how he met my mum!)

Dave

Edited By SillyOldDuffer on 22/11/2017 17:01:11

Talking of funny rope-related names, I was initially surprised to see one of these described as a "thimble". Funny folk, sailors.

Murray

I can tell you aren't a 'sea-scouty type'

Neil

I've shown this before, similar arrangement of strap, gip and cotter to hold a bearing in place:

Posted by Neil Wyatt on 22/11/2017 18:58:10:

I can tell you aren't a 'sea-scouty type'

Neil

Hmm, actually that's where I learnt about all that stuff. When I was in my early teens, we lived near the sea on Belfast Loch (during The Troubles) and I became very interested in sailing, amongst other things. Obviously my Scottish parents weren't about to buy me a boat so the only way to get my hands on one was through the local Sea Scouts - cue silly hats, whistles, marching about etc. Learning all the knots and parts of the boats was a piece of wind and soon I was out and about in their boats (mainly Mirrors) during the weekends and evenings. Did my RYA Dayboat certificate etc and a few minor events before my dad closed down the local ICI plant (Kilroot, manufacturing PET) and we moved back to God's Country.

Murray

Please accept my grovelling apologies!

I assumed you had only just learned what a thimble was. I'll hank a sack of ropes and do twenty back-splices as atonement!

I did a lot of time on Mirrors and occasionally a Heron. Mostly kayaking though, started on wood and rubberised canvas ones but latterly mostly Snipes IIRC which were great fun for surf canoeing (my record was 13 capsizes in one day...)

Neil

Interesting question Colin and thanks for posting the picture. It’s nice to see the basic forgings (if that’s what they are are) next to the finished components. It seems to be to tension something but I’m a bit surprised that no one on here has been able to give you a concise answer yet.

My father also noted that this exercise separated those "engineers" with only machine training (e.g. lathes and milling machines) from those that could turn their hand to anything. He didn't know what the things were until he examined one of the early locomotives of the Canadian National Railway at Halifax, Nova Scotia after his ship's (HMS Malaya) crossing of the Atlantic with gold bullion on board destined for safe keeping in Fort Knox (27th Feb - 4th Mar. 1940).

Speaking of lathes - he also told a tale that illustrates the British attitude to war. During one of the many Mediterranean actions that HMS Malaya was involved in, my father went ashore and found an abandoned German lathe. He got the rest of the engine room artificers to row to shore, load the lathe onto the boat with some difficulty and row back to the ship. With difficulty, the lathe was winched up the side of the battleship where the ship's Captain was waiting (hidden). As my father put his head over the side, the Captain said "Lloyd - is that lathe yours? The reply was "No". "Lloyd - you will return it to where you found it". So different from the Nazi attitude to personal items.

The reason that apprentices were given such tasks was not because they were likely to be a regular part of their later life. They were tasks which included a variety of hand and tool skills, requiring in addition a degree of organisation, and discipline. Knowing that anyone passing the test was able to produce stuff - any stuff, not obsolete steam engine fittings - using these skills was a big encouragement to employers.

Is that the sort of answer that will suit?

Cheers, Tim

In a previous job we introduced an assignment as part of some of our recruitment; it was to see if people could produce a decent, if short, piece of written work in response to a relevant scenario given quite a brief length of time - 20-30 minutes.

I was given an assignment like that in the mid-seventies when I went for a job with one of the big engineering companies. The answer came back that they didn't have a vacancy that suited my skills, but they had passed my details on to their research establishment . After a further interview I ended up working there instead.

George

He must have had great skill to be able to produce those screw threads with just a hammer, chisel, and files

Russell

Unfortunately, I only began to transcribe his war memoirs after he died. Or else I would have asked him the same question - along with many others that arose during my attempt to read his difficult hand-writing.

Oh, those pre-war types, skill unsurpassed to this day, now that was chiselling within an inch of your life. 14tpi to be exact.

Michael W

I have no idea why they are called thimbles - but they were an essential part of the long steel cables I used to support tall aluminium scaffold towers that I built over both UK forests and tropical rain forests in Brazil and Cameroon - the tallest being 52m high, 27 sections each 2m x 1.5m x 1.96m tall. Photo shows one of the towers in J--Parana, Rondonia, Brazil.

The same could be said of the standard apprentice piece, the 1 inch cube and the hole through which it had to pass (just). Good eye, steady hand and attention to detail. 'nuff said?

Neil,

Do you still have your Marlin Spike then?