TPS doesn't go into detail on the shape of chokes, and the tools, and I suspect Peter Johnson's references are, while historically correct, representative of early manufacturing techniques.
Charley Parker sold a lot of tooling and misc. parts to Gary Herman. Gary subsequently passed them on to me. Amongst the tooling were chamber rim cutters, and a wooden box containing more than a complete set of reamers. Many of the reamers were stamped with the full name 'Hayes' and in some cases, the initials J.H. (James Hayes)
Most of these reamers were threaded on the driving end, and one or two may have been square headed, which was the typical configuration of normal machinist's tools. "Nut Cutters" may have referred to a type of reamer (still listed as such) with a hex head, though I'm not certain of this.
The Hayes reamers with threaded ends were complete with the rods used in the boring machine. The consisted of a Morse Taper end, which was, and still is, used to couple the tool to the spindle. The rods, all about 3' long, had an adjustable stop ring. The far end was female threaded to accept the reamer itself
All of Hayes' reamers were of straight taper design, which leads me to believe, that at some point, the method, and reamer shape described in Johnson's book was no longer used. As Hayes was chief tool designer, and maker, as well as a brilliant engineer, I believe he may have played a role in Parker adopting a new choke design.
The same tool was used to bore all constrictions. This was determined by the depth, limited by the stop ring, that the barrel moved into the machine. The further it went, the larger the tool was at the point it exited the barrel. This naturally accounts for the reason that tighter chokes are longer chokes.
I have since passed all these tools onto another member/collector, who has amassed a more thorough collection of early Parker tools and history. I was especially glad they went to him because he has a family connection to James Hayes.
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