SEM article

I thought so, thanks Paul. I've been having a delve and I'm wondering if Worthingtons didn't borrow a design from their cousins across the water? They were into two stroke crosshead engines amongst other types. It looks very much like some of their engines.

Tom

Almost certainly a US design, found a section of the fuel pump in a US text book.

Had some contact with W-S and they know nothing, they even searched the drawing office records but came up with mothing.

Cheers Paul

Have you checked out Worthington Pump & Machinery Corp engines?

Tom

Whitworth - 55 degree included angle, round top and bottom

UNC/ANC/UNF/ANF/SAE 60 degree included angle, flat top and bottom

If that were the case, Fred, why change the name? UN series have 60 degree with the root & crest of the bolt rounded, as is the root of the nut but the crest of the nut is flat.

Tom

AIUI, pre-wwII there was SAE (Society of Automotive Engineers), which was adopted as AN(F, C), American National Coarse / Fine, which the UK adopted as part of rationalization during Lease-Lend, and became Unified Normal Coarse and Fine both sides of the Atlantic.

Brown & Sharpe threads were also common in the USA, pre-WWII

I suggest you actually do some research on the Unified Screw system, Fred and clear up some of your misconceptions..

Tom

I _did_ say "AIUI"

If you know better, please tell. I will gladly benefit from your knowledge, as I hope will other readers.

Quoting acronyms is an excuse?

However, in a nutshell, due to problems encountered manufacturing equipment to British specifications that were to be assembled with fasteners of a thread form alien to NA etc during WWII, the three countries covened a design team produce a common thread system. The result : Unified System was designed and adopted in 1949. This used the 60º angle of the US Sellers aka AN system due to the ease of the angle generation and used the rounded crest & root of the Whitworth Thread Sytem, thus overcoming the inherent deficiency of the American thread form. The deficiency being the flat at the root of the thread, the resultant stress riser causing failures in highly stressed components.

E & OE

Tom

No, a reminder that my post was not meant to be authoritative, but an invitation for comment/correction.

I bow to your superior knowledge. Thanks.

Always.