It is so Frustrating!

E

Ed in Maine

Well-known member
First, I want to say I did find the answer to my question on the screws needed for mounting the windshield in my Cabriolet, they are No. 12 x 24 x 5/8 in. What is the story with the No. 12 thread type? I dread encountering these screws every time I come across them. It usually means a special order if you are lucky enough to find them. I usually use "The Bolt Depot.com". But, back to my windshield, I have a couple of holes in which I cannot start the original screws that came with the car into the cowl frame. Try to find a tap for the no. 12 screw. I just got off a web site in which I got all the way down to placing the order for a no. 12 tap and they tell me their minimum order is going to be $25.00 plus shipping for a $3.75 tap! Why was this thread type so common on the Model A but so seldom used today? Ed
 
I have a few old tap and die sets in the old wooden trays, they have all the obsolete weird sizes and are good USA quality. Yard sales and auctions often have them.
 
Look for them on eBay. I have had good lucky finding #12 and other screws that are plated on eBay. Sometimes they are a little pricey, but I usually find what I am looking for.

Rusty Nelson
 
Another vote for McMaster-Carr, good quality tools and parts at a descent price with fast shipping and no Min. order
 
the screws on every Cabriolet windshield hinges that I have worked on, 68B`s & C`s are 1/4 20 X 5/8 not #12. not sure on the 68A
 
There is a Fastenal store in our town. They have the screws, may be able to get the taps. Could try looking them up on the net.
 
Those "numbered" screw sizes are a mystery to me and I have no idea where to go to buy them. It seems they were never used here and are regarded as some weird "used in America only" system. The best I can usually do is tap them out and use a metric (easily available) replacement.
IMO, the sooner you guys go metric, the better off you will be.
 
My modern cars are metric. The local Lowes hardware store and the auto parts stores have metric.

Synchro, If you need any numbered screws, please let me know and I will ship you some, no charge. As you know, the old RR are Witworth. Try finding that hardware here in the states, or even the wrenches.
 
nkaminar said:
My modern cars are metric. The local Lowes hardware store and the auto parts stores have metric.

Synchro, If you need any numbered screws, please let me know and I will ship you some, no charge. As you know, the old RR are Witworth. Try finding that hardware here in the states, or even the wrenches.
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Neil, My modern cars are metric. I assume you are talking about US made cars. There is much of those cars that is made in metric countries (China) and only assembled in the US, hence the metric threads. That being so, a conversion to metric would not be much of a stretch these days IMO.
The only difference between NC (National Coarse) and Whitworth threads up to 1/2" is the form of the thread. One is 55°, the other 60°. With a little drag, one will fit the other but not have the strength the correct nut/bolt would have. When you guys adopted NC, I don't know why they made such a ridiculously small change to Whitworth. Were they thinking they were creating something new? From 1/4" to 1/2", they have the same thread count but at 1/2", Whitworth was 12 TPI while NC is 13. The sizes of the bolt heads and nuts works a different way too. There is a formula to calculate the spanner size for say, 3/8" Whitworth but I am not aware of anything to determine the size of NC nuts. Never the less, the AF system makes more sense to me than using that formula.
There are only three countries in the world that still use imperial measures, the U.S., Liberia and Myanmar. Conversion is a matter for each of them alone.
 
IMO, the sooner you guys go metric, the better off you will be. __________________


like asking Americans to convert to soccer over football. wont ever happen.
 
America tried going metric, voluntarily, in the early 1970's. It was a flop. People just didn't want to change.
 
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