Does anyone know where to purchase bulk castle nuts (in various sizes) with the flat bottom cotter areas? I know the early cars are supposed to have the flat areas as opposed to rounded, and since I have every nut and bolt (mostly common hardware store replacements) off the frame, I figure I may as well find the correct flat slot castle nuts! Surely someone is reproducing these critters!
I've seen some on the Mcmaster Carr website
The McMaster catalog has castle nuts and the picture shows flats in the bottoms of the castle. They also have the nuts in stainless steel.
Low-Strength Steel Locknuts for use with Cotter Pins
Also known as castle nuts, secure these nuts by inserting a cotter pin or safety wire through the slots and a drilled hole in your bolt for mild loosening resistance. They’re not recommended for use on parts exposed to high vibration because the pin is prone to shearing under prolonged stress. Height includes the slots. Cotter pins are not included. A zinc plating provides corrosion resistance in wet environments.
For technical drawings and 3-D models, click on a part number.For technical drawings and 3-D models, click on a part number.
Size Wd. Ht. For Cotter
Pin Dia. Min.
Slot Wd. Min.
Slot Dp. Pkg.
3/8"-24 9/16" 21/64" 7/64" 0.12" 0.11" 25 95030A160 $6.85
Figured out how to post the page....
Too bad they don't offer them in black; I contacted them and they only come in zinc.
A little muriatic acid and Oxpho-Blue will fix that problem pretty quick.
look for boxes or cans of model T nuts and bolts at swap meets or from other car guys.
I do like Kim, but I think Langs has them for under $1 each. My local hardware store gets over $2 each!
Most castle nuts available today have 100% machined features. Pretty sure the version from the T days had the castle features cold headed and have totally different appearance than modern ones, at least for the most common 3/8" size. Larger sizes appear to have been machined same as today.
You can find coffee cans of them at Hershey. Even more challenging is finding Heavy duty machine nuts. These are the thick, over-side nuts that were used on brass era cars. I found several coffee cans of them a few years back at a local swap meet. At 20 bucks for the lot, it was a bargain.
I am unsure about the definition of "early" castle nuts.
Below is a picture of the three types usually seen on Model Ts
The nut on the left is usually seen on connecting rods and rarely elsewhere.
The center nut has the flat bottom and is not very common in my collection.
The right nut has the rounded bottom and in my experience is the most common.
Which of the these is considered "early" or is their a fourth type?
The castle nuts supplied by Langs appears to have the round bottom, where those by McMaster are square.
OK; FWIW, I spent half a day researching this at the Archives. I looked at all the available drawings and releases of castle nuts, some dating from 1907. None--not one--showed flat bottom slots. All were round, including the nuts used on the earliest Ts. Yet seemingly original cars have flat slotted castle nuts. Why is this? My own opinion is that Ford really didn't care about whether the slots had flat or round cotter pin slots, as long as the nuts fit the bolts and had the right number of correct sized slots. Therefore the Ford inspectors accepted many thousands of boxes of castle nuts with flat cotter pin slots.
Later on, when Ford was making their own, they made them according to their own drawings.
Anyway, that's my theory and I'm rigidly adhering to it. Sorta.