I have an old Pratt & Whitney lathe and I need a drill chuck for the spindle sleeve. Does anyone know what kind of cone I need? It's definitely not a morse cone, since I already tested it. Since I can only post two images, here are the dimensions of the cone:
smaller diameter: 9.2mm
larger diameter: 12.2mm
length: 57.8mm
There might be some error in measurement.
This article Suggests that M1 tapers are standard but there are examples with Jarno tapers.
Your measurements seem closest to Jarno #4 but don't match exactly
This page has tables of the common taper sizes so you may be able to deduce it from there.
The Pratt & Whitney Precision Tools catalog says these had a Jarno #4 Taper in the tailstock. [url]https://archive.org/details/precisiontools00pratrich[/url]
