Double twist horn mounting screws

[Tbird]

I'm sure this is probably an easy answer, but can someone please comment on what screws are used to mount a double twist horn to the firewall. Size, shape and length appreciated.
Thanks
Mike

[Hudson29]

Mike, I hope you get an answer to this as the single twist horn on my '14 has mismatching screws and I would like to find the correct items.

[Piewagon]

Oddly enough almost everything that mounts to the wooden firewall on the early cars uses a round head brass #9 wood screw. The horn, stewart speedo mount, mixture adjuster mounting plate... The only thing I can think of that did NOT use a #9 was the firewall to floorboard shield and those where held to the firewall with #6 round head brass screws until after 1915 sometime. In the T era the odd numbered screw sizes were just as plentiful as the even number ones but later and to present day the use of odd number screws has diminished enough that most stores no longer carry them. The dash is 3/4 thick until early 1915 when it changed to 11/16 thick but you should allow for the thickness of the item you are mounting and also then figure about 5/8" penetration into the dash. You don't want the screw to stick all the way through the dash and pop out on the front side or back side if mounting from front to back.

Hope this helps.

[Hudson29]

Thanks John, that gives us a place to start. This would be a good item for our vendors to stock. I found a package of 100, I need only two.

[Tbird]

This place seems to have some vintage screws that you can purchase by the piece.

https://gatelatchusa.com/home.html

[Original Smith]

My '13 uses two #9 X 7/8", but this isn't the horn you were asking about is it?

[ThreePedalTapDancer]

Who has a source for #9 screws?

[R.V.Anderson]

I have the correct ones. #9 x 7/8" round head steel as John Regan and Larry Smith have said. I don't believe the screws changed unless the earliest were round head brass, but they would have been the same size and type.

[Hudson29]

Thanks for the info, its nice to know ahead of time what to order. I'm going to need another pair of screws for my project. My '14 was converted to electric lights at some point. I have a '15 magneto light switch to replace the non-working switch that is on it now. This will need some smaller screws, probably oval head. Anybody know what size these should be?

[Hudson29]

I just ordered the screws from Gatelatch on their website. The screws themselves were a relative bargain but the shipping was very dear. It probably would have made sense to order a pile of different screws for stock. I just did not want to spend the time on this order, too many other things going on.

[Original Smith]

Blacksmith Bolt in Portland, Oregon has a very good selection of original style bolts and nuts. They still have slotted screws. They don't have any hex nuts however. The original owner sold out, but they are still in business.