I'm now the new world class expert on lathe spindle noses.
What makes me an expert is I spent the money and got USAS B5.9 (1967 r2004). It was a simple matter of a download from the website. I have all the information on the A1 and A2 (there is a difference) D1, L series etc and all the details and little standardized parts, cams, cam lock studs, detents, ring nuts, keys, locating disks, and all the other details.
For instance there is a 2" size A1 spindle nose and there is a 28" size A1 spindle nose with 3 4 5 6 8 11 15 20in between. See, I got it in a PDF file from the standards outfit and now I got it on paper. Everything - and it's from a standard which is de facto law in the technical world. That's what makes me an expert. For a zillion years whenever I had to rassle with a spindle or fit an item of spindle tooling I've been frustrated, handicapped, stabbing in the dark, sweating whether a detail I'm working with will turn the machine into a white elephant because I changed something that was standardized or something non-standard. Now I have it on paper. If I'm in doubt I can get out the standard to verify the rightness of my actions.
The whole idea of standards is so the many things we make and use interchange to the maximum extent possible. A chuck made in Poland or Connecticut will fit a spindle made in Cincinnatti, Edo, Shanghai or - Mars. Same with bearings, bolts, materials, etc.
So thanks to a $35 charge on my card I'm as expert on spindle noses and abutting features as 44 pages of ASA B5.89 drawings and text can make me.
From this new experience I'm inspired to encourage all of you to maintain a library of technical information starting with "How to Run a Lathe" "A Treatice on the Milling Machine" and similar how to's. And how could a home shop ever get along without "Machinery's Handbook" or some other compendium of standards and narrative related to the machinist trade. Also handbooks and trade school texts for welder, millwright, engineer, etc wherever your curiosity takes you. If you are not adding a foot or so the the length of books and looseleafs, catalogs etc on your shop bookshelf every year you're not really trying. Well, maybe that's an over-statement but to adapt a saying: if you think information is wasteful and expensive try ignorance.