Can anyone tell me what the thread form should be on the engine mounting studs for a ’47 engined Squirrel. I measure 55 degrees (optical comparator) and 20 TPI on the old studs. Not 5/8 BSF, too many TPI and not a cycle thread, which is 60 degrees. ❗
Laurie, thanks for the input, 5/8 – 20 with a 55 degree angle is what I measure. I can now go ahead and machine cut the threads on my new studs. Richard, I’m so sorry I did not learn of your services sooner. I’ve just returned from a visit to your neck of the woods and would liked to have met you and seen your facilities.