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Joined: Dec 2001
Posts: 217
Backyard Mechanic
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OP
Backyard Mechanic
Joined: Dec 2001
Posts: 217 |
Ok all you Chevy experts, here's one for you. My 1928 Coupe has what the parts book calls an Instrument Carrier Plate. This is held in the dash by four wing nuts (part number 120838). The book calls for them to be of size 10-32. Unfortunately, I only have 3 of the four nuts. No problem. I went to my parts bin and grabbed a 10-32 wing nut and crawled up under the dash of the car. Nope, too small. Back to the parts bin where I grabbed a 1/4-28 wing nut and headed back to the car. Nope, too big. The nut slips. Once again back to the parts drawer where I found a 12-24 wing nut and once again headed back to the car. Wrong threads. Back to the car, this time with a thread gauge. Conclusion: 1. My back hurts. 2. The nut required is a size 12-28 which I can't find and for which I don't have a tap. Is this one of those odd-ball sizes like the choice of 1/2-12 head bolts? Why would it differ from the size listed in the book? Happy New Year! 
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Joined: Nov 2001
Posts: 19,758 Likes: 64
ChatMaster - 15,000
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ChatMaster - 15,000
Joined: Nov 2001
Posts: 19,758 Likes: 64 |
Well, Well, :( I first checked my Feb. 1, 1930 4 cylinder parts book and found both the 10-32 (pn 120838) and 12-28 (pm 353494) wing nuts listed.  I then went to the Feb. 1, 1928 parts book and found only the 10-32 wing nut listed. Oops, :confused: looks like there must have been a mid-year or factory change. Good luck in finding one of those little fellas. I will know to keep any that I find for the '28 I need to build. Thanks for the heads up, Rusty. :love:
How Sweet the roar of a Chevy four!
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Joined: Dec 2001
Posts: 10,379 Likes: 1
Technical Advisor ChatMaster - 10,000
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Technical Advisor ChatMaster - 10,000
Joined: Dec 2001
Posts: 10,379 Likes: 1 |
The April, '28 parts book hangs tight with both wing nuts 10-32 & 12-28. The 1/2 ton truck however likes Hex, Machine Screw Nut 10-32. 
RAY Chevradioman http://www.vccacolumbiariverregion.org/1925 Superior K Roadster 1928 Convertible, Sport, Cabriolet 1933 Eagle, Coupe 1941 Master Deluxe 5-Passenger Coupe 1950 Styleline Deluxe 4-Door Sedan 1950 Styleline Deluxe Convertible 2002 Pontiac, Montana, Passenger Van 2014 Impala, 4-Door Sedan, White Diamond, LTZ 2017 Silverado, Double Cab, Z71, 4X4, White, Standard Bed, LTZ If you need a shoulder to cry on, pull off to the side of the road. Death is the number 1 killer in the world.
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Joined: Oct 2002
Posts: 1,050
ChatMaster - 1,000
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ChatMaster - 1,000
Joined: Oct 2002
Posts: 1,050 |
Was this around the time the Society of Automotive Engineers (SAE) started standardizing thread sizes for the industry? -Bob
-BowTie Bob
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Joined: Dec 2001
Posts: 217
Backyard Mechanic
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OP
Backyard Mechanic
Joined: Dec 2001
Posts: 217 |
Thanks for the information. ChevyChip: I was going from the 2/1/28 parts book so that explains why I couldn't find pn 353494. :rolleyes: Now I just need to figure out where to purchase or fabricate a 12-28 wing nut. :( -R
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Joined: Jan 2002
Posts: 242 Likes: 1
Backyard Mechanic
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Backyard Mechanic
Joined: Jan 2002
Posts: 242 Likes: 1 |
Hi guys i think that you will find that the thread is 1BA that is British Associated it is 28.25 threads per inch and has a diameter of .208" all the 28's here in Australia have these retaining the instrument plate ,possibly your car has the export car screws fitted.and these to are not listed in the parts books ,not even the export issue, and i agree with chip the parts books don't help a lot if you want a good laugh try looking up the sunvisor braces I did 8 different books all GM and there is 5 different numbers for the same listing.as for the head bolts 1/2 12 these to are BSW british standard whitworth. ? I dont no why . if you have no luck with the wing nut let me know and i will send you one Jim
Jim
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