Where to get the screw that holds the Governor in a 706 telephone?

[Tiggermoth]

Ha!

The postman has been and delivered some soggy post from Nigel (it's Manchester weather here).

One screw did arrive safely, but the other two are having a party somewhere. They managed to burrow their way out. They're free after thirty years stuck in a telephone!

Thanks ever so much, I can fix one dial now!

Mark - I may need to pop down and see you after all?

T

[mark_in_manc]

Sure - send me a PM

[Tiggermoth]

Mark,

Thanks! It looks like I'll be alright after all, Nigel has managed to find another one and he's very kindly sending it to me (along with a couple of other dial bits too). What a man!

Update: I tried M3 screws and they are too small. So I've got a bit more confidence in my measurement of 3.1mm after all now.

Out of interest though, how easy would it be to make some of these? It does seem to be that they deteriorate and tend to shear off after all those years.

Thanks ever so much,
T

[bluepilot]

Originally Posted by Tiggermoth

Out of interest though, how easy would it be to make some of these?

How long is a piece of string? If you had access to a lathe it would be quite easy. Probably only a few minutes work. If not it gets more difficult. If you weren't too bothered about it looking the same as the original you could probably do it with a pillar drill. Get a lump of brass rod of the correct outside diameter, drill a hole in the end and cut a thread on it, assuming you have the correct die. Maybe if you had a steady hand you could even drill the hole with a hand-held drill but you would still need the correct die to cut the thread. Maybe you could even get some threaded bar with the correct thread but you would still need to drill the hole in the end.

[TonyDuell]

I think getting the hole accurately on the centre and along the axis would be very hard with a pillar drill.

And the rod has to have a shoulder on it, the threaded part is smaller diameter than the 'head' so it can be tightened against the dial chassis.

My view is that it is going to be a lot easier with a lathe.

The centre hole is critical. From what I remember, the governor is needed when the dial is rotating anticlockwise to the 'noemal' position. So the intermediate gear is rotating clockwise and the governor spindle is thrust towards this screw/bearing. I am not sure what the end of the hole should be like. I am not convinced a normal twist drill is ideal here. Possibly drill almost all the way with a twist drill, then finish up with a D bit. To counter that, I did make one from a 5BA screw, just drilling the centre hole (in a lathe) with a normal twist drill and it works, but I do not know how long it will keep working for.

I can add 'make this bearing' to my to-do list, but again I don't know if it will last. And I am short of tuits (circular).

[bluepilot]

Duh! Yes, forgot the obvious one of drilling a hole in the end of a 5BA screw (or whatever thread it is)

Originally Posted by TonyDuell

And the rod has to have a shoulder on it, the threaded part is smaller diameter than the 'head' so it can be tightened against the dial chassis.

That's what I meant about not looking the same as the original. You don't necessarily need the head. Cutting a slot in the end of a rod for a screwdriver would probably do. Fix it with Loctite. Would give you better adjustment as well. You wouldn't need to get the depth of the hole exactly right.

I think you could probably drill a hole in the end of a rod if you carefully centre-punched it first but obviously a lathe would be much better.

[julie_m]

Put the brass rod in the chuck of a drill, in reverse, and bring it towards a drill bit held steady in a vice? That should give you an accurate centre to finish the job in the "conventional" fashion, though a pillar drill or at least a drill stand probably would still be required.

[mark_in_manc]

Originally Posted by Tiggermoth

Out of interest though, how easy would it be to make some of these? It does seem to be that they deteriorate and tend to shear off after all those years.

Have a look at '5BA brass cheese head' machine screws on (say) ebay. There's just about enough head to grip squarely in a collet, which means you can drill and part to length in a lathe. In fact, you could buy some and shorten / drill them in my (unheated) shed on my lathe while I get the kettle on...if you need showing how, then fine. Couple of minutes each, once you're set up and you have the screws bought in to start with, rather longer to make from round bar. Yes, what's at the bottom of that hole is unknown - I'd drill it to start with and see if it works.

[Tiggermoth]

Thanks all for your replies. Every day is a school day!

Yes, I've now had a search, I've seen that 5BA brass cheesehead bolts are available. So that would definitely be a good option. Thank you.

Nigel has very kindly sent me another one of these little screws in the post (thank you again Nigel) along with some other bits too. Brilliant stuff.

So it looks like I'm alright for them for the time being.

After going this far in the search for them, I am pretty tempted to have a go on a lathe to make a handful though!

T