[TR] Replacement bolts

[Angelo Graham]

Hello List:
  In attempting to replace some of the nut/bolts in my TR2 project, 
have found it difficult to find the exact bolt, especially for bolts 
with unthreaded shanks in various lengths. How important is it to get 
bolts with the exact unthreaded shank length? Most of the 
replacements I have been able to find are threaded the complete 
length. Does this present a problem when replacing an unthreaded 
shank bolt?? Thinking mainly of the driveshaft flange bolts and rear 
backing plate/axle attachment bolts.
I've always understood that most of the fasteners are "fine" thread - 
NF. Have seen listings with threads per inch of 24, 20 and 18 on 
larger bolts all as "fine" or NF. Am I missing something here or all 
they all considered "fine" and vary by size of bolt.
Thanks for any help with this.

Angelo Graham