A side – and personal - note on torquing circa the Model A period. My Dad was a mechanic, starting as a P-38 mechanic for Lockheed Aircraft Corporation in Burbank CA before the war (that’s WWII for you younger types) and eventually becoming a tool and die maker for Lockheed Missiles & Space Company in – as I recall – Van Nuys CA (before they relocated to Sunnyvale CA). He claimed to have bought his first Model A when he was 15 or 16 (which would have been in 1936-7) and we once – after I became a mechanical engineer – got into a discussion of (basically) “How did you old guys do it in the ‘dark ages’ without torque wrenches?” whereupon he said that he could come to within 5 ft-lbs just by feel. Being a young (that’s a relative term) whipper snapper, I set up a fairly good sized double-nutted bolt in my vice and asked him to prove it (I had my trusty deflection-bar torque wrench at the ready to check his accuracy). As is usually the case in these instances, he was spot on each and every time, which brought new meaning to “Son, don’t mess with me” and provided some insight into why – back in the so-called “dark ages” – torque wrenches might not have been as prevalent as they are today.
By the way, I still have one of his Lockheed pay stubs from March 8, 1941 (before he was invited to spend time in New Guinea and Luzon with MacArthur’s army). He earned – for a 40 hour week - $20.40 and took home $18.90 (deductions were $0.20 unemployment insurance, $0.20 “Fed. O.A.B." – whatever that was, $0.58 for group insurance and $0.52 miscellaneous deductions). And – with those earnings – he was able to co-own a private plane (until December 7, 1941, when the government shut down the air space over Los Angeles) and live comfortably.