Carcano barrel thread measurement

[Lebel]

I want to try and cut this Carcano thread on my lathe but none of my metric or imperial gauges are giving me a good fit. 14 tpi WON'T work. I can't remember, but is there some mathematical way of figuring this out. A bit embarrassing for a guy with machine tools to admit but I always went with the gearbox chart.

 

[pjs]

The pictures show it coarser than 1.75 and finer than 2.0. You need to be in-between those so I would bet that it is a 14 TPI. When you say you go by the gearbox chart do you mean you are selecting for a 14 tpi and it is wrong? In which case you may have the wrong gears installed.
Pete

 

[Grizzly Adams]

Could cut a dummy to check.

Grizz

 

[FredSKS]

According to " Bolt Action Rifles", it should be a 1.065" dia. with Approx. 14 V T.P.I. I guess Frank de Haas wasn't too sure, either !