Robertson screws

[oldspert]

My 1929 was built in Canada and I am wondering if the Robertson thread pitch is US or Metric? I am missing some of the screws and need to order some replacements. If they come in US thread pitch, it will not be a problem finding them, but if Metric ??

[ronn]

unless you are doing a Marc show car, why worry?

[ArchieAeh]

Canada did not switch over to the metric system until the seventies. You should be safe with regular pitch.

[Model "A" Fords]

Originally Posted by oldspert

My 1929 was built in Canada and I am wondering if the Robertson thread pitch is US or Metric? I am missing some of the screws and need to order some replacements. If they come in US thread pitch, it will not be a problem finding them, but if Metric ??

The Robertson screws are not Metric on your 1929 Canadian car. They will be standard stuff like #8-32, #10- 24, #10-32..... just like you have on US cars. There was someone in US that was making reproduction Robertson screws, I don't recall the name.

In our local hardware store I picked up brand new Robertson style stainless steel screws. I knew they were very slightly different and the stainless is a different color than Nickel. They were on the car in plain view for ten years and I wondered when someone would notice them as to me they were obviously wrong.
The person that noticed them finally, was a Canadian Judge. He was the only one and he wasn't very close to the car but spotted them through a closed window. He went by them and said " you know those screws are wrong, I have a few left that are correct!"

That's what I love to here! I was beginning to think nobody could see a difference.

[Bick in New Zealand]

Can anybody tell me the thread size for the screws that hold the rear window frame together for open cars, as I need to find a source for the Robertson version.

[fundytides]

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#5-40. Let me know if you find any. I would like to have some as well.

[Bick in New Zealand]

Originally Posted by fundytides

#5-40. Let me know if you find any. I would like to have some as well.

Will do.

[fundytides]

I could also use some #5-40 cage, or just regular, nuts to repair my original window frame

[rackops]

I haven't been able to find Robertson screws in anything other than #6, #8, #10, and 1/4. The cars take a #5 and #12, but I can't find them anywhere.

Yes, I have asked a LOT of people and always get the "I can find all the Robertson screws I ever need at the local store!" But, of course...never a size #12. I've even reached out directly to manufacturers, and...nothing. I can get 1000 made for 60 cents (US) each, but that gets to be an expensive hobby.

[Russell Reay]

Originally Posted by rackops

I haven't been able to find Robertson screws in anything other than #6, #8, #10, and 1/4. The cars take a #5 and #12, but I can't find them anywhere.

Interesting observation. I thought I was experiencing a manufacturing glitch when I discovered none of the hardware stores in my area carry #12 screws. I don't need Robertson, but blade or phillips #12 would be handy without buying little packages dedicated to a single application

[nkaminar]

Can you re thread the #6 to get #5? What about making some yourself with your lathe? I guess the hard part would be to form the square hole. Probably better to modify the #6 screws.

[oldspert]

Originally Posted by Russell Reay

Interesting observation. I thought I was experiencing a manufacturing glitch when I discovered none of the hardware stores in my area carry #12 screws. I don't need Robertson, but blade or phillips #12 would be handy without buying little packages dedicated to a single application

I have found some stores have 3/16 course thread screws which is actually a #12-24.

[nkaminar]

So #12 is actually 12/64 size? Does that mean that #10 is 5/32 and #8 is 1/8, etc.? I am reaching for my calipers.

[Model "A" Fords]

Originally Posted by nkaminar

So #12 is actually 12/64 size? Does that mean that #10 is 5/32 and #8 is 1/8, etc.? I am reaching for my calipers.

American Standard #8 - 32/36 Basic outside thread diameter is 0.164"

British Standard 3/16 - 24/32 Basic outside thread diameter is 0.1875"

American Standard #10 - 24/32 Basic outside thread diameter is 0.190"

American Standard #12 - 24/28 Basic outside thread diameter is 0.216"

American Standard 1/4 - 20/28 Basic outside thread diameter is 0.250"

[oldspert]

Originally Posted by nkaminar

So #12 is actually 12/64 size? Does that mean that #10 is 5/32 and #8 is 1/8, etc.? I am reaching for my calipers.

Has nothing to do with other sizes. Just commenting that 3/16 is sold in some hardware stores and is the same as a #12-24 or #12-32.

[Pete]

Try Tacoma Screw Products. They have been able to get me some really oddball screws in the past.
Also, try gunsmithing supply places. That is a standard size gun screw.

[mcgarrett]

Also check out McMaster-Carr. https://www.mcmaster.com/

[johnneilson]

Originally Posted by nkaminar

So #12 is actually 12/64 size? Does that mean that #10 is 5/32 and #8 is 1/8, etc.? I am reaching for my calipers.

No, the standard numerical sizes as follows;
starting with a "0" the major diameter is .060

add .013" for every number up

"2" is .060 + .026

"4" is .060 + .052

this from 7th grade machining class, I guess schools are missing out now...

J

[Halswell]

Interior Robertson screw kits for most of the A body styles are available from Mikes "A" Ford-able Maysville GA. WWW.mikes-afordable.com. Right there in USA
Robertson screws used in the Canadian A's are imperial /US system threads.
Hope this is of help. Windy here in NZ.
Happy Motoring

[katy]

Has nothing to do with other sizes. Just commenting that 3/16 is sold in some hardware stores and is the same as a #12-24 or #12-32.

3/16" is not the same as #12, it's the same as #10. #12 is between #10 and 1/4"
See post #14