Description

• This nut is a stainless steel cap over a heavy forged nut.
• There is no rust anywhere; another sign the cap is stainless.
• Stainless has a couple of tiny indention’s.
• Threads are fine.
• It measures 1″ ID with 32 threads.
• The OD is 1-11/32″ with a height of 0.320″.
• Original 1954 GM parts manual PN for this nut was 1922539.
• It is described in the parts manual as “1-32 threads, w/ 3 wrench slots”
• There is no OD given in the parts manual nor height.
• Part # changed to 1929529 in July 1955 just prior to the start of the 56 model production.
• Part 1929529 is described also as “1-32 threads – w/3 wrench slots & an OD of 1-11/32”.
• Again, the height of the nut is not given in the GM parts manual.
• We measured the height of the threaded part of a 53-55 switch ignition switches & a 55-57 switch.
• The 53-55 switch measures 19/64″ to where the nut would bottom out.
• On the 55-57 switch, this measurement is also 19/64″.
• The total thread height on the 53-55 switch is 3/16″ while on the 55-57 switch the total thread height is 5/32″.
• As such the 56 & later nut will stick out ~1/16″ higher than the original 53-55 nut.