Wireless Set No. 52 Canadian - Project

[David Dunlop]

Chris.

That is fantastic news on so many levels! At the very least, it reaffirms my reputation as an Eccentric, Detail Mad Goof!

Very early on in this Project, I could not wrap my head around the data related to the hardware Canadian Marconi Company used to mount the 52-Set components into either the Carriers No. 4, or the Remote Receiver Case. All good, available photos from its time in service indicated hex head fasteners were in place. When the actual components started to arrive, sure enough, ¼-inch, 20 hex nuts and bolts were in place in all the expected locations, in different lengths.

The problem was, none of these hard facts lined up with the information in the Operators Manual, or in fact, the Tool Kit issued for the 52-Set. There is no 7/16-inch spanner or wrench provided to deal with hex bolts quickly and easily, and no complaints in this regard ever surfaced from the British during their trials of the set. Odd.

Second, in the Operators Manual, CMC points out in several locations that the set is reliable enough the Operator will never likely ever have to pull individual components for servicing, and all routine maintenance can be performed via the various removable panels and doors. The British Trials confirmed this. Where the Operator might run into conditions requiring removal of more than one component from the Carriers No. 4, CMC does warn the Operator it will be necessary to pull all three components and remove the Connector Assembly across the back of the Carriers to reinstall all components. This is a highly unusual circumstance, and yet, still no warning from CMC about any lack of proper tools for the Operator to do the job. Odd again.

Recently, I discovered that the upper hardware on my Remote Receiver was installed backwards according to a number of photos I had seen. Photos showed bolt heads to the outside, mine were reversed. When I flipped them around, I could not remove the upper receiver panel. The hex nuts and split washers stuck too far out on the inside of the case. One more thing that did not add up.

Now, two years after receiving Richards photo of his original Remote Receiver, I finally see the hardware used was a thin head, slotted hex bolt. That fits perfectly into the puzzle. In the 1930’s and 1940’s the slotted screwdriver was supreme in the average toolbox, spanners and wrenches were typically for working on things more robust than a wireless set.

A similar concept applies to the hardware used in wireless sets. Split washers seem very rare to none existent in British wireless equipment. They nearly always use a much thinner, internal toothed Shakeproof washer to lock things down. They take up less space.

The final interesting thing I have noticed with the larger hex hardware used on wartime wireless equipment is that the hex nuts are a lot thinner than their modern equivalents today.

My thought on all this latter stuff is that post war, spanners, wrenches and drive sets of various sizes became very popular tools everywhere, very rapidly, for two big reasons: speed of use and the massive increase in torque one can apply to the hardware. That probably spelled the end to the wartime, thinner hex nuts and bolts. It would become extremely easy to over torque this older hardware, rounding off the corners on the nuts and bolts and probably even shearing off a lot of bolt heads.

Consequently, here in Canada at least, whenever the 52-Sets went in for servicing, or maintenance of any kind, it probably became standard practise to simply remove and toss the factory original hardware and replace it with the more robust, modern stuff designed for use with modern, high torque tools.

Nice that Richards Remote Receiver survived in England all these years with little change.

Not so nice I now have to find a bolt shop somewhere that still stocks old style, thin head slotted hex bolts and old style thin hex nuts.



David

[Grant Bowker]

Not directly suitable but indicates that at least someone wants slots and hex heads on the same fastener...
https://www.mcmaster.com/screws/hex-...slotted-drive/
Were fasteners on the 52 set like those on the 19, often BA threads?

[David Dunlop]

Hello Grant.

Yes, a quick glance at the Web yesterday suggested there were a number of companies making modern slot head hex bolts. I fear the trick will be finding a company still making the vintage thin head versions.

The hardware mix on the 52-Set is consistent with that found on the 19-Set and very likely all other wireless sets of British origins, used by the Canadian Military. The BA Thread generally tends to be found, however, in just a few particular components. The Pocket Watch Holder mounting hardware is a classic, along with bits of the Tuning/Flick Drive Assemblies.

What I have noticed is the BA Threads are common enough they are listed in the Standard Hardware Lists compiled by the Ordnance Supply System. Interestingly, these slot head hex bolts do not show up on the Standard Hardware List at all for the 52-Set, so they must have been placed elsewhere in the system.

One thing I did find this morning is the ¼-inch ID split lock washers typically found on the ¼-inch mounting hardware today on the 52-Set Components, do not exist on the original Standard Hardware List. The much thinner, Shakeproof, ¼-inch ID internal toothed lock washer is the only one listed. That would be consistent with the idea the original hardware was beefed up with modern replacements post war, for convenience in servicing.


David

[David Dunlop]

It certainly is easy with large projects like this to lose track of what you have actually accomplished. There is a tendency to fixate on the things that still need to be done.

I have decided to step away from the major components for a while, for several reasons, not the least of which is to clear my head a bit and deal with something entirely different. Towards that end, I am going to tackle restoration of one of the Microphone and Receivers Headgear Assemblies, Cdn, Type 10 that I have for the set, One is complete and in very good shape, though yet untested. The second one is all there, also untested, but has issues, so I shall tackle it first.

The Illustrated Parts List for the Wireless Set No. 52 is helpful in that it shows the major pieces for the Canadian Headgear Type 10 and provides good written descriptions of them, but that is as far as it goes.

On the bright side, however, the FZ 256 Illustrated Parts List for the Wireless Set Cdn No. 19 Mk III and Ancillary Equipment, has very detailed exploded view illustrations of all the parts of the Canadian Headgear Type 10 covering virtually all of the little bits and pieces. You can see clearly where everything goes, and even better, all the hardware is shown, with relevant descriptions and part numbers.

The four photos posted today show the complete headgear assembly that requires restoration, and the three reasons why.

The first major problem is that somebody cut the leads off one receiver assembly for some reason. There is no sign the setscrews on the receiver have been touched, which is odd. These receivers were used in a variety of headgear throughout the war. In most instances, the leads would have a small brass ring terminal stapled to the end. The staples cut into the covering and insulation of the lead and connect with the central copper core of the lead. The two small screws on the back of the receiver would be removed and the ring terminals fitted over the screw and everything reattached. With the Type 10 Headgear, the end terminals on the leads are just brass staple sleeves about ¼-inch long. These are then slid into holes in the receiver below the two brass screws. The screws are simply backed off enough to allow the end terminals of the leads to slip all the way into the holes and then the screws tightened down as grub screws.

The second problem is the typical massive coat of NATO Green paint brushed on the microphone and which is badly chipped. That needs to be dealt with somehow.

The last issue I am currently aware of is the state of the heavy-duty oilcloth neckband cover. Years of exposure to Brylcreme and being rubbed between the back of a Wireless Operator’s neck and Battle Blouse have worn the cover down to its cloth core.

So let the games begin.


David

[David Dunlop]

After thinking about the repair process for the damaged Headgear Assemblies Type 10 for a while, the task began to make less and less sense, in regards to salvaging/repairing the cut Receiver Lead. Apart from not having any equivalent terminals for the original brass staple terminals that had been cut off, more importantly, I would have to trim back that lead a good inch or more to get enough free wire from the two conductors with which to work. That whole process would have ended up pulling the entire cord assembly off to one side of the headgear, which would have looked very odd. So I felt a bit bummed for a while until I remembered finding an NOS headgear cord many years ago at a flea market. A half-hour of foraging through boxes and bins and I found it.

And what a nice surprise! It turned out to be a complete replacement cord assembly for the Type 10 Headgear and the loom was a perfect colour match for the two drop cords on the Main Set Supply Unit.

The other Type 10 Headgear Assemblies I have will become my spare. It has a lighter colour loom, very close in appearance to standard wartime 1937 Pattern webbing. So this is starting to work out rather nicely. The service photos I have seen of the 52-Set, wartime and postwar, all show the single Operator’s headgear connected to the right drop cord on the Supply Unit. I suspect the Cypher Clerk took advantage of the speaker in the 52-Set Receiver to monitor traffic for coding purposes. Most photos show the left drop cord connected to a Jumper Cable feeding over to a Wireless Remote Control Unit No. 1 and from there, probably off to a Land Line connection. If the left cord is not in use in this manner, it is sitting empty on its Supply Unit clip.

The first two photos today show the complete NOS CORDS and a close-up of the terminal fittings. The microphone fittings are at the top – the small brass ring terminals. The two receiver leads are below showing the plain brass staple end terminals.

The second photo also nicely details the larger brass crimp that secures the end of the cotton loom from moving, or unravelling. The outer end of this particular crimp has a loop pressed into it and you will see a small S-Ring fitted to each of these loops. This is the Anti-Strain that takes the weight load of the entire headgear assembly off the electrical terminals on the receivers and transfers it to the Bakelite body of the receivers themselves. More on this in a later Post.

The third photo illustrates the Grip & Clamp Assemblies fitted at the main wiring junction of the CORDS. I always assumed this assembly contained all the terminal connections between the Y-Plug, microphone and receivers. Turns out it is merely a two-piece fitting that fits over the pre-existing junction already woven into the CORDS loom.

The two parts of this item are PLATES, Phenolic, Front & Back, Grip & Clamp Assemblies. Front – ZA/CAN 5244, and Back – ZA/CAN 5245. The two parts are held together by four sets of brass hardware (screws, flat washers and internal toothed lock washers). ANC, Brass, RH, 4-40 x ½ inch.

The back of the Grip & Clamp Assemblies has a large spring clip fitted to it. The Operator uses this to attach the CORDS to the front flap of his Battle Blouse in order to take the weight of the entire headgear assembly off his neck.


David

[David Dunlop]

When RCA Canada developed the Headgear Assemblies, Cdn, Type 10 for the Wireless Set No. 52, they incorporated the pre-existing Receivers, Watch, MC 50-Ohm (ZA/CAN 0842), which had been used on some of the headgear made for the Wireless Set No. 19. They did so, however, with a couple of interesting changes.

They took advantage of the push in connection feature of these receivers, rather than using the terminal screws to mount into ring terminals on the leads. This may have solved a couple of related problems in the field. The screws no longer have to be completely removed to replace a defective Receivers Watch MC, so the screws are less likely to be lost. Additionally, placing the lead connections inside the Receivers, Watch MC gets them out of the way of excessive moisture/rain, which may have been causing difficulties.

The second change RCA made was in adopting the small metal S-Rings for the Anti-Strain devices on the Receivers, Watch MC. On the Wireless Set No. 19 headgear using the Receivers, Watch MC, a smaller metal crimp clip was used to secure the loom on the Cord up by the Receiver leads. Woven into the loom at these two ends was a length of what looks very much like a length of thin, brown or black, shoelace. When the Cord is fitted to the Receivers, this lace is looped through the Bakelite Anti-Strain loop cast into the side of the Receivers below the terminals and then woven around the leads to transfer the weight of the Cord off the terminal connections. The excess lace is then trimmed away leaving a telltale little stub about ½-inch long sticking out.

The first photo posted today shows the broken connection on the Type 10 Headgear I have to replace. The S-Ring is still in place on the receiver loop. The second photo is of a headgear assembly from a Wireless Set No. 19, using the same Receivers, Watch MC. You can clearly see the brown Anti-Strain lace woven around the connections. It is possible these cotton lace Anti-Strains were subject to rot, and subsequent failure, so RCA went with the metal S-Rings.

Also worth noting in the second photo is the massive amount of red lacquer used to cover the two terminal screws. Very little is evident in the first photo where the connections are now inside the Receivers, Watch MC.


David

[James D Teel II]

I’m very interested in how your restoration of the No.10 headset works out for you. I have a virtually NOS No.10 that I use to listen on my 19 set, but it won’t transmit. I think I probably still just have a series of bad voicemitters because the set keys up when I hit the pressel switch, but I get no side tone.