1922539 Archives - Corvette & Classic Car Parts Store

Ignition Switch Mount Nut, Original.

John — Fri, 04 Aug 2023 22:29:07 +0000

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.

John — Fri, 04 Aug 2023 22:24:10 +0000

This nut is a stainless steel cap over a heavy forged nut.
There is no rust anywhere; another sign the cap is stainless.
It has several indentions and score marks on the outer perimeter from pliers being used to remove it in the past.
Chrome is also faded
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.

John — Fri, 04 Aug 2023 22:21:32 +0000

This nut is a stainless steel cap over a heavy forged nut.
There is no rust anywhere; another sign the cap is stainless.
It has some indentions and score marks on the outer perimeter from pliers being used to remove it in the past.
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.