Thanks.
#5 - The Atlas 618 (1937-1972) and Craftsman 101.21400 (1957-1972) had Timken tapered roller bearings. The first MK2, Atlas 3950 and Craftsman 101.21200 (1973-1977), actually had ball bearings (probably a misguided bean counter decision). The Atlas 10100 (and metric model 10200) (1977-1980) went back to Timken tapered roller bearings.
#9 - The Compound Slide is the topmost part of the carriage assembly (not including the tool post, turret or Quick Change Tool Post). It has a machined flat area on the end normally away from the operator that has a T-slot cut through it for attaching the tool holder. On the end of the compound slide usually nearest to the operator is a crank (or sometimes a small wheel) attached to the compound feed screw..By turning the crank, you can move the compound slide away from you or toward you. Attached to the machined flat on the near end of the slide (between it and the graduated dial) is the compound feed screw thrust bearing plate. On the early version round-top compound slides used on all 618's, 3950's and 101.21200's and the first few hundred 10100's this was a long-oval shaped plate attached with two screws. On the later 10100's (and as shown in both 10100 manuals), this plate is rectangular and still attached with two screws. "Diamond shaped" is a poor description. I just edited Question 9 to read "long-oval shaped. All of the 10100 manuals show the flat-top slide and late rectangular thrust bearing. But early production continued to use the original round top slide and oval bearing plate. We were just interested in learning at what serial number the actual change was made. Roughly the same is true of questions 3, 4, 7 and 10. We still have little clue as to when the final change to a Zamak headstock was made as almost none of the Zamak ones have survived.
#11 - Gear M6-102 is Item 37 on page 12.1 of the 3950 manual, Item 38 on page 12 of the 101.21200 manual, Item 38 on page 12 of the early 10100 manual and Item 37 on page 12.1 of the late 10100 manual and Item 38 on page 12 of the Metric 10200 manual. All manuals are available in Downloads. The late carriage has the more complicated assembly with provision for adjustment of the mesh or back lash between the M6-67 pinion and the M6-102 gear. Most people who have reported having the late carriage with the adjustable mesh have said that they wish that they didn't.
#12 - When I wrote the original questionnaire, I inadvertently mis-numbered questions 12, 13 and 14 as 13, 14 and 15. A fair number of replies were received before someone commented on it, and I didn't want to change the question numbers of 13, 14 and 15.
