Firewall Screw/Bolt Size?

[406CID]

I don't have access to a 28 or 29, but my both my 30 and 31 firewalls take a 10-32 screw in the clip that secures the generator cutout wire to the firewall at the terminal box. Can anyone tell me if 28/29 also takes a #10/32 screw?

Mike's says it's a 12-24 for 1928-1931:
http://www.mikes-afordable.com/product/A14577BR.html
but I know that's not right, since both of mine are 10-32.

I'm trying to put together a wiring kit that picks up a chassis ground at that point. I plan to include the right size screw in the kit and the harness needs to have the right size connector. But what's the right size? #10 or #12?

Thanks,
Kyle

[denniskliesen]

Mine is a early 29 and where there are D nuts on the firewall below the tank are all #12-24. Also I used the D nut located between the steering column and the cowl panel for a chassis ground, I believe it is a screw for the floor plates around the steering column and foot pedals.

[aermotor]

I have a 28 and it is 12-24 same as speedo cable clamp screw.

John

[2manycars]

A 10-32 will fit, sorta, but the correct screw is 12-24.

[406CID]

THANK YOU ALL SO MUCH! You guys saved my backside on this project. 10-32 is the right size for my 30/31 firewalls. Factory D nut, and there is just no way to get a #12 in that hole. I'm glad I didn't assume the earlier models were the same before making the harnesses. It's odd that Mike's catalog says the 12-24 fits 30/31 firewall when it clearly won't work on either of mine.

Thanks,
Kyle

[Bob C]

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I checked a couple of my 1930-31 and they are 12-24.

Bob

[aermotor]

Snyder's catalog shows 10 - 32 D nuts as being in the cowl and door area and refers to pages 82 & 83 of How to Restore Your Model A, Vol. 2. Might want to check there to see what is going on.

John