Re: Were Packard built Merlins metric, ASA, whitworth or ???

Posted by Owen_Dyneto On 2012/9/1 15:24:04

According to Robert Neal's superb book on the Packard aircraft and marine engines and paraphrasing a bit from it, the British RR Merlin used 4 different threads, British Association (BA), British Standard Fine (BSF), British Standard Whitworth (BSW), and British Standard Pipe (BSP), plus a few that RR modified themselves. About 140 different external threads were used on the engine. One of Packards' significant problems with the contract was duplicating these threads, finding vendors to make the necessary thread tools, etc.

If the topic interests you, buy Mr. Neal's book, it's reviewed in the "Packard Bookshelf" on this website.