Saving Old Seagulls

Hi, I am trying to identify the exact size of the two retaining screws for my Amal twin-jet throttle lever. It sits on a Silver Century WS.

I suspect the screw is a BA 1, the approximate dimensions are 5mm od and 5/16" length with a rounded slot head. Is this about right?

Thanks in advance

1 BA is 5.3 mm diam and 0.90mm pitch. thats 28.2 tpi

Odd numbered BA sizes are very unusual ( except in older electrical stuff)

do you not think it is 3/16" Whitworth. 0.1875" diam (4.76mm), 24 tpi


Same control as the Villiers carb AFAIK and they are 3/16" Whit in that! The diameter is a bit under spec but 24 tpi no doubt but 7/16" long

Thanks Vic, I was being a tad lazy in not getting the Micrometer out.

But I suspect you are probably correct.

Cheers

Thread size is 1BA. You can get stainless or chromed ones from Custom Fasteners in Newtown - they have a website - customfasteners - oddly enough - that you can order from.

Vic wrote:


Same control as the Villiers carb AFAIK

Not really. Have a look at :

http://www.britishseagullparts.com/engine-throttles.htm

I haven't got any better "one I took earlier" pictures to hand and it saves wearing keyboard fingers for the rest of it............


Peter

Should have mentioned that Custom Fasteners don't supply rounded headed screws - only 'cheese headed' type, but these are normal to the type of lever I think you have from the sizes you are quoting.
The earlier levers had screws with a raised countersunk head, and from memory I think were a finer thread.

Thanks Rick,

yes I saw that and have ordered the 1BA cheese slot head