Wireless Set No. 52 Canadian - Project

[David Dunlop]

I have pulled this photo up again because it shows really well the four sets of components that are fitted to the wooden case for the coil, once the coil assembly itself has been removed. In order to refinish the wooden case, all four of these sets need to be removed. These components are as follows:

1) Aerial Output Terminal - located on the upper left rear side panel. The tip of the socket assembly for it is just visible in the upper left corner of the photo.

2) Input Terminals - there are two of these fitted with wing nuts located one on each lower rear side panel. The inner brown phenolic mounting strips are clearly visible inside the back of the case.

3) Panel Mounting Brackets - three each across the upper and lower front of the case.

4) Case Mounting Plates - mounted to the bottom of the case, one each side.

It should be noted, that with the exception of the casual mention of the two above terminals in the Operators Manual, none of these IDs are official and none of these parts can be found in either Issue 1 or Issue 2 of the Parts Lists for the 52-Set. Some of the individual parts making up these items are listed, however, but not all. I guess I should also point out here that I recently ran across a few pages from an Issue 3 of the Parts lists, dated 2 January 1953. I have no idea at this point if this was a few random page updates, or another full revision.

I shall cover the removal and descriptions of these four components in the next four posts.



David

[David Dunlop]

The first component I decided to remove from the coil case once the coil assembly had been removed was the Aerial Terminal. Not because it is in the way of anything else to be removed, but for the simple reason it is the most fragile component, which sticks out too much. The two main pieces of it are also in the realm of Unobtanium should they be broken.

This item is not referenced at all in the Parts lists as a complete assembly at all, but three components of it are, as follows:

1) INSULATORS, Ceramic, Bushing, Female ZA/CAN 4596

2) INSULATORS, Ceramic, Bushing, Male ZA/CAN 4661

3) SOCKETS, Antenna, w/sleeve, No. C1 ZA/CAN 4593

The last component is cadmium plated, 1/2-inch brass hex rod, fitted on its outer end with the cadmium plated brass socket with sleeve. The inner facing end is fitted with a 10-32 x 2.75-inch cadmium plated brass rod.

A pair of .020 inch thick brown phenolic gaskets fit between the insulators and the wooden case, one each side. These were custom made for the application. I found both of these gaskets had become glued to the NATO Green paint since 1966 which was a little concerning. I found bt using a 4-inch steel putty knife at very shallow angle, the paint was thick enough I could slowly press into it to get the blade below the gasket and slowly lift it. As the gasket slowly came up, I gradually advanced the blade until the entire gasket popped free. This worked for both the inside and outside gaskets.

These three pieces are clamped to the left side of the wooden coil case with a 1/2-inch OD 10-32 plated brass flat washer, plated brass 10-32 Shakeproof washer (internal tooth lock washer) and a plated brass 10-32 hex nut. When the connection is made to the internal feed from the tuning coil assembly, a 7/16-inch OD 10-32 plated brass flat washer is slide down against the hex nut already in place, the feeder cable fitted and then a second 10-32 Shakeproof washer and hex nut added to secure the connection. I am missing the second Shakeproof washer but have a few extras in my parts supply for when reassembly takes place.


David

[David Dunlop]

This arrived today from Amazon.

When I discovered I was dealing with an aluminum plate for the front panel of the Coil, Aerial Tuning No. 2 A, I realized I had not had any aluminum primer on hand since I worked on my WIRE-5 project back in the 1970's. Back then, the 'Go To' primer for aluminum was the green Zinc Chromate stuff used in the aviation industry and I was able to source cans of it from Perimeter Aviation here in town. I was not at all surprised to discover the price of this stuff has gone through the roof since the 70's.

When checking for alternate products on the web, this product came up and caught my eye because it is a white primer, not the old green I had used years ago. When I was restoring the various cast zinc knobs and handles on the rest of the 52-set a few years ago, I had to find a correct primer for working with zinc or galvanized items and the product I found was also white. So I will be using the same process for the front panel of the tuning coil. A first coat of the white aluminum primer. let is cure and give it a coat of standard grey primer and then the top coat.

Just a can of xylene to track down now and I will be good to go for spray painting down the road.


David

[David Dunlop]

The six Front Panel Mounting Brackets are another undocumented item in the Parts lists for the 52-Set. They are made from 1/8-inch thick by 1/2-inch wide, cadmium plated brass bar stock, cut into 1.5-inch lengths. These are them formed to create a 1-inch long bar with a 1/2-inch tab folded at 90 degrees at one end. Centred along the one inch base are two 11/64-inch holes, themselves centred 7/16-inches apart. The small tab is centre drilled and tapped to accept the cadmium plated RH slotted brass 8-32 x 3/8-inch panel mounting screw.

All six Front Panel Mounting Brackets are identical in their mounting to the wooden coil case with a pair of cadmium plated, 6-32 x 3/4-inch RH slotted brass machine screws, brass Shakeproof washers and brass hex nuts. If your Coil, Aerial Tuning No. 2 A has never been overhauled, or rebuilt, you will find once all the brackets had been installed, the hex nuts were secured with a dab of red lacquer. The one slight exception to the mounting process is found with the bracket in the lower front right corner of the coil case. This bracket has an additional brass fitting attached to it as part of the grounding arrangement for the aluminium plate front panel of the completed tuning coil. This fitting will get some separate coverage later, but since one end of it is also connected to the special front end machine screw for the right side Mounting Plate, these Front Panel Mounting Brackets need to be removed now to gain access to the Mounting Plate hardware later.



David

[Barry Churcher]

David, Xylene is available at Princess Auto for $14.99. I just got some there.
Barry

[David Dunlop]

At first glance, the two Input Terminals on the Coil, Aerial Tuning No. 2 A appear to be the most basic of parts. Then, when you get your first good closeup look, they suddenly turn into one of the most fascinating assemblies in the entire 52-Set.

These two Input Terminals are located on the lower rear corners of each side of the coil case, directly above the rearmost mounting screws for the two brass Mounting Plates located on the bottom of the coil case. As such, they need to be removed before the two Mounting Plates can come off the case.

On the inside of the coil case, you can see the brown phenolic resin plates securing the two Input Terminal assemblies to the sides of the case. These plates are 3/16-inch thick, 1-7/8 inches long and 3/4-inches wide. they are held in place by an upper and lower set of cadmium plated, RH slotted brass 8-32 x 3/4-inch machine screws, brass Shakeproof washers and brass hex nuts. As a first step, DO NOT attempt to undo this hardware and remove the plate assembly.

In designing the 52-Set, Canadian Marconi Company was concerned the Operators, under less than ideal conditions, could lose critical hardware, like wing nuts and lock knobs. They used two techniques to avoid such losses. One was to drill the tips of screws, mount the wing nut, or knob, and then fit a wire D-Ring through the hole to secure the hardware from loss. The other technique, as they employed here, was to fit the wing nut and then use a small punch and hammer to mushroom the tip of the screw slightly to prevent the wing nut from coming off. So neither the wing nut, or small mounting panel, will through the hole in the side of the coil case. However, if you first remove the hardware from the central terminal stud on the inside, things will become possible. From the outer end of the stud to the phenolic panel, there should be the folllowing plated brass hardware:

1) 10-32 hex nut
2) Shakeproof washer
3) 10-32 hex nut
4) Shakeproof washer
5) 10-32 flat washer.

With all this hardware removed, and with good lighting, you will notice a 1/4-inch ‘square nut’ in the middle of the panel. if you apply pressure with a thumb to the exposed stud in front of this ‘square nut’, while at the same time gently pulling and rocking the terminal on the outside of the case, this stud assembly will pop free of the phenolic panel. You can then undo the hardware securing the panel and remove it from the coil case.

Interestingly, this terminal stud is the only part of these Input Terminals toi get mention in the Parts Lists for the 52-Set. They are machined from 1/4-inch square brass bar stock and are identified as:

STUDS, Brass, Special, ANF 10-32, 1-21/32 inches long, No. C1. ZA/CAN 8048

The finished item was cadmium, or zinc plated, and there is enough information in the description in the Parts Lists that a decent machine shop should be able to replicate them today.

With the two Input Terminals safely removed from the coil case, the only components left to remove are the two Mounting Plates on the bottom of the case.


David

[David Dunlop]

Hello Barry.

Thanks so much for the tip. It is the exact same product as I found here at RONA for six dollars more. I shall be launching a Princess expedition shortly, but I must say, I do miss the ones when their yard was full of rows of half tracks, CMP's and WIRE-5 boxes, and mind boggling other bits.



David