C42 part number wanted
 

A large “captive locking screw” that threads into the ATU and slips onto the spike (support, antenna, ZA29831). What is the part number for this “captive locking screw” - as it is described in operating instructions for C42 in 1/4-ton , 3/4-ton and National Survival manuals. The threaded stud is a British thread. The “ears” on this screw are often bent close to the sides so it can be turned and tightened when the ATU is being attached on the spare tire bracket antenna mount on Canadian jeeps. Finally why does the spike have crude threading: it simply slips into the lower hole of the captive locking screw when putting the ATU on the ground. A set screw clamps it in place.

The manual for the M152 lists it as p/n 351569. Haven't found any Z number yet. The coarse thread is for standard D rod aerials. Maybe re-using what they already had. For ground mount you want a quick disconnect.

The block is used to attach the wing box with the ATU to a Land Rover wing - as such it's inside the wheel arch (I think) and needs to be fairly (!) robust.

The coarse thread for the spike is so that it can be used with the ZA.5325 Antenna Rods 'D', Spike when you need to remote the aerial from the set.
(There would have been thousands of those available as they replaced the 34-FT Steel Vertical Aerial with the Mast, Telescopic, 27-FT.)

...Now that's irritating: I've just been and looked on the C11/R210 trolley and the block there only has two fixed lugs and a third screw-in one to clamp the block to the spike (the hole in the underside is not threaded for the spike).

....Further irritation: that's the later version (circa 1963) shown in Radio Installations in FFR 'B' Vehicles, where it is simply described as "the heavy clamping screw" and the corresponding base spike is mild steel and unthreaded. It must be listed somewhere else as part of the "Demountable ATU", but I have no idea where.

Chris.

In the EME manual L271 the threaded spike is driven into the ground. The ATU No 6 assy is placed on top and secured by tighting the captive locking screw.

I've spent the last 2 hours looking for the spike and block but no joy. I suspect a northern border raider might have absconded with it.

Guilty as charged m'Lud.

At least I suspect so, since it was in that pile of cables and stuff I bought along with your C11, some years back. (I still remember the last 30 minutes of that trip, in which the Satnav decided to _only_ direct us down 'C' roads and farm tracks.) :mad:

I'm sure I have the earlier type of block - with 4 fixed lugs - somewhere.

Spikes are fairly plentiful, blocks less so because nobody recognises them as radio related kit.

Chris.

Bruce: Could you check your number 351569. In my books it is the "Antenna base and tuning unit assy, CDN", 5985-21-108-2632, ZA 47032 MOD, 351569. I don't think it includes the part in question: just the tuning unit in the box with the base (rubber cone) on top. I'm not sure what the Canadian Mod. was to the tuning unit that made it different than the British version. Where there was a special or modified part used by Canadians then a NATO stock number had the "21" country code and a number of the same format as 351569 was assigned. If there was a ZA number for a part that was modified then it was described as ZA XXXXX MOD.

I'm fairly certain the bolt is part of the wing box, since that is what fixes it to the vehicle wing. (There's a separate reinforcing plate supplied as part of the FFR kit, but that is considered to be part of the vehicle.)

It may well have an FV number rather than a ZA one.

There do not appear to be any part numbers stamped on the bolt I have.

Best regards,
Chris.

Hi Chris.

The Canadian Training/Instructional C42 Sets used that same huge nut to secure the ATU Wing Box Assembly to the large sheetmetal bracket on top of the set. The Dummy ATU mounted on the back wall of that large bracket to the right of the working ATU. Pain in the fingers trying to get at that nut!

David

Brian, looking at another page in the EME it would appear that you're correct. The enclosed page shows that 351569 is secured by a heavy screw (item 4).
There is no number for the part.

Chris, the route is designed to thwart invaders and pirates. :)

Thank everyone for your comments. I was hoping to be able to accurately describe and give a part number to this part for my inventory. I have exhausted my Canadian references including the Canadian microfiche. There are no part numbers on the "captive locking screws" that I stock.