Cathy,
Yes, the caps can fall off and get mixed up. I just got a bunch of shuttles like that and had to use the Boye tin pictures to figure out what they were. Like you mentioned some are slightly different than pics, usually the thread path at the tail end.
Boye 20 can be used on any Davis machine using Davis long but it is not quite the right needle. I looked in Ismacs needle list and get "Davis H.A. [<#37500]" for application. The serial number might be good but Davis only had a Low Arm model in the early 1870's when 37500 was made. Also states Davis long used on "Davis H.A.[>#37500]". I can count on one hand the number of Davis machines I've seen lower than SN# 37500.
I believe the White Peerless and early White models and use the Boye 20. I'm not well versed on White though and at one time I asked about it in a forum and got no response. The 1x1 is used on quite a few early machines other than Davis and White. I got 75 hits on the ismacs needle list when searching "1x1" though some might be for 1x11.
Jon
Last edited by jlhmnj; 04-20-2015 at 11:50 AM.