3/16” castellated brass nuts

[Denis Sweeney]

Been searching the web for a small supply of 3/16” brass castellated nuts to fit the studs from the aluminium actuators for semi girling brakes, to no avail. 
Does anyone know of a stockist?
I am given to understand that 2BA is, for practical purposes, the same as 3/16”BSF?
Cheers Denis S

[Stuart Giles]

10-32 UNF is a closer match to 3/16" BSF than 2BA. these might work for you: https://www.ebay.co.uk/itm/NOS-10-32-UNF...3787682232

[Chris KC]

What Stuart said. Though for my money I'd settle for a BSF nut of different type before resorting to UNF; and use other means of locking (lockwashers, Loctite, wiring, etc.)

[Steve Jones]

I've used 10-32 UNF Nylocs for this and they work fine. Nylocs might not please the purists but I take the view that the object of the exercise is to stop the nut falling off.

Steve

[Tony Betts]

try looking for "slot nuts" instead of castlated.

tony

[John Cornforth]

Hi Denis

With plunger activated "Full Girling" brakes, the brake actuator is allowed to slide slightly in the backplate, to equalise the pressure on the two shoes. This is achieved by using slightly slotted holes, plus thackeray washers and castellated brass nuts which are only done up tight enough to give a sliding fit. Tiny split pins stop the nuts coming undone.

Austin kept cams for actuation in their "Semi Girling" interpretation, so in this case the actuator has to be held rigid. However, the castellated nuts etc were kept, maybe in the interests of standardisation by the supplier ?

I suspect that ordinary nuts plus shakeproof washers and/or loctite would therefore suffice.

[Henry Harris]

Mine are 1/4" BSF

[Denis Sweeney]

Many thanks for the information folks. My Ruby is an early type which had been converted at the rear end to semi-girling in a previous life but with the original lozenge front brakes, which were fitted to the the last of the early Ruby’s.
I am now converting the the front to semi-girling to match the rears.
My brother has a big seven and a a late ruby based special and he had sent me details of his set up and a photo of all the parts which replicates exactly what John has detailed.
Thanks for your explanation John it all makes sense now as the backplates on my rear brakes and all the parts I have for the fronts have no slotted bolt holes or oval holes for the actuator to allow any movement to equalise the brake loading.
Cheers Denis S