Murphy B40D Lubrication and gearboxes.

[Tyso_Bl]

I've just recently brought home a Murphy B40D bought from a rally a couple of weeks back, I'm getting the mechanical bits in order first.

First off I've a choice of three types of grease available, Lubriplate white grease, Molybdenum Disulphide extreme pressure grease, or standard Lithium based grease.

I've used the Lubriplate white grease on the drive chain and sprockets, and also in the Muirhead slow motion drive for the oscillator trim capacitor. Only now am I thinking that the Lithium grease may be a better choice instead, has anyone a recomendation for this.

What about gearbox lubrication? the high speed one at the bottom of the radio needs done as its slightly notchy in one place, the upper one I don't know yet but seems ok.

As I don't have access to a "gold standard" radio, I'm not able to work out if the upper gearbox mounts should be rubber bushed. on loosening the mounting screws the gearbox was able to float around making drive chain adjustment impossible. I've fitted metal bushes to take the slack up, and it works well, but I'm not sure if this was how it was intended to be. The manual is not clear on this point either.

All thoughts welcome on this.

Tyso

[g4aaw pete]

Hello Tyso
although I have a B40 on the bench, I've yet to wresle with the machanics of it.
The B40 manual suggests the use of 'anti seize' grease.

However, I've serviced several Eddystone dial mechanisms, and have used Molly grease to lubricate them.

Good luck
Pete

[Sean Williams]

I have restored several B40s.

Lithium grease is fine for all of the gearboxes, a touch of light oil on the shafts also helps.

Word of warning - the main tuning drum can be a little frustrating to reassemble and align in the tuning window mask - the height is adjusted by the setting of the main vertical shaft - takes some fiddling!

[Tyso_Bl]

I've opted fot Lithium grease in the gearbox, the stuff in there had set in places, lovely piece of engineering it is.

The tuning scale drum was a problem here, the radio had been apart in the past, lots of missing grub screws, washers and so on.

I've managed to get the mechanisms back together and working as the should, but took most of yesterday to do it.

Can you tell me how the upper low speed gearbox is supposed to be mounted to the frame? I've undone a previous bodge, but can't find how it was originally done.

Originally Posted by g4aaw pete

[snip]
The B40 manual suggests the use of 'anti seize' grease.
However, I've serviced several Eddystone dial mechanisms, and have used Molly grease to lubricate them.

I'm just wondering what 'anti seize' grease is, special additives or something.

I dislike using Molly grease on anything to be used indoors, it seems to have an unpleasant smell to me. I also recall something about it being more suitable for sliding / shearing type lubrication rather than the rolling of ball bearings. Its also very messy to work with!

Which version B40 have you got?

Tyso

[Sean Williams]

I have a B40C in bits (it is incomplete)

I am now waiting to find a better example.

I am away from home at present, but could probably get some piccys when I return - the whole front is off, so sorting out the gearbox piccys will be simple.

[Radio Wrangler]

The usual anti-seize grease is white stuff intended for car brake mechanisms, the adjusters and handbrake cams which live inside brake drums. I's high melting point, but most importantly, it's a grease designed to not go walkies even when hot. You don't want your brake linings to get lubricated. It is indeed suitable for radio tuning gearboxes and I've found it a good substitute for the rarer Lubriplate stuff. The slightly different name "Anti seize compound"is usually used for stuff like Copaslip which is normally used on threads to stop them seizing when hot.

David

[Tyso_Bl]

Thanks Sean,
some photos of the upper gearbox mounting arrangements would be helpful, there is no rush about it whenever is convenient to you.

I'm also trying to find out what the service modifications are, the sticker on the front shows 1-7 have been done.

Attn David, Thank you for the information on the greases, I've settled for Lithium in the boxes, and Lubriplate for the chain drive. I bought the Lubriplate about 25 years ago, only have half of it left now. I have used proper clear Dow Corning silicon grease for high temperature non creep work, but again messy stuff to use.

Tyso

[Silicon]

Lubriplate seems to be a brand name like Castrol or Duckhams.

Your tin of Lubriplate could be a white lithium grease.