Needles and their lengths

[sjharumph]

Have been experimenting w/ various needle bars/gears/racks, etc across several Patch machine manufacturers.   Ex.  An Adler 30-1 needle bar is $500+ but the Singer 29K71 needle bar is $50 and is a slightly different length.   Ex. The Taking TK2971 is a decent Taiwanese machine but not as durable as Adler/Singer so we hybridize it w/ 29K71 parts.    Making less expensive or better quality parts work is a necessity.  W/O adjustable needle bar height,  the only alternatives are to 'adjust' the 29x3 needles using the clamp or to hopefully determine and procure the correct length needles which is where I ran into the issue I need help with.    Nowhere on the web, and I'm good w/ this stuff, can I find a reference chart that will tell me the lengths of commercial needles.    Ordered some 332LG 120/19 suitable for Adler 30-5 and 30-7 but they were too long and didn't have enough shank to grind off the necessary amount.   What I think I'm looking for (to make Singer 29K71 needle bar work in Taking TK2971) is a 50mm overall length needle.    Scarf and thread hole issues aside,  I'll start w/ length and go from there.   I probably should have just called Glenn but I thought I'd ask everybody.   Thanks!    Once we get past  this issue then it's on to solving the Adler 30-1 $400+ and impossible to find shuttle carrier.