Hub thread pattern

[CompClassics]

On the "55" stamped original production line knock-offs the "55" indicated the thread pitch. Dan made reference to a manufacturer change, it was from Harvey to Alcoa, I believe Alcoa bought Harvey.

[Dan Case]

Originally Posted by CompClassics

On the "55" stamped original production line knock-offs the "55" indicated the thread pitch. Dan made reference to a manufacturer change, it was from Harvey to Alcoa, I believe Alcoa bought Harvey.

Correct X2

As far as I know Halibrand made KOs were not stamped with 55 until 427 Cobra street car completion started. Speculation on my part is that parts for GT40 MKIIs might have been on hand by that time???? Cobra race car owners don't want the stamp while 427 Cobra owners do. Did you know that it was not rare for CSX33xx cars to be delivered with steel nuts on one side of the car and aluminum ones on the other side? (Circa 1969 Halibrand released a new steel nut with rounded ends on the wings. Guess where I see them most? On CSX33xx cars. I just cannot help but wonder if owners / dealers took the opportunity to have all four nuts on late cars the same design and material? Interesting to think about since some cars didn't get sold new until 1969. That gets to the issue of what "original" means to different people. Was "original" for many details, as cars left for delivery to a dealer or after dealer preparation for the first buyer.) Details, details....

Also GT40 MKIs converted from wire wheels have the same thread. GT40 MKII and MKIV have different threads and were normally dyed red or blue depending on direction of threads.

I have collected samples used or nos of every brass, cast steel, forged steel, and forged aluminum straight arm, forged aluminum curved arm, KO AC Cars, Shelby, Holman-Moody, FAV, or Kar Kraft used between the first street Cobras and last GT40 MKIV except the steel ones used on most 427 street Cobras. I have found some but each time a 427 Cobra owner pleaded to get “the last part” they were after. I have recorded which Cobra, 427 Cobra Comp car, MKI, MKII, and MKIV the used ones of those types came from. I have a front from a Daytona Coupe removed in 1968 but I have forgotten the chassis number and have not yet tried to figure it out again. I have a set of wire wheel nuts for a GT40 MKI but the chassis number has been lost to time.

Original wheel hubs and center lock nuts is a very complicated subject!

[Kit Coyle]

Will the "55" thread pitch steel knock off fit on a "60" pitch ERA six pin hub? Are
the hub, wheel and knock off bevel angle the same ? When did Halibrand
make the forged aluminum spinners with the small word "Halibrand" on each
of the three ears? I have the P.S. Engineering FIA wheels and the aluminum
"Halibrand" spinners as supplied by ERA.

[Dan Case]

Originally Posted by Kit Coyle

Will the "55" thread pitch steel knock off fit on a "60" pitch ERA six pin hub? Are
the hub, wheel and knock off bevel angle the same ? When did Halibrand
make the forged aluminum spinners with the small word "Halibrand" on each
of the three ears? I have the P.S. Engineering FIA wheels and the aluminum
"Halibrand" spinners as supplied by ERA.

Question 1: Me, I have no idea. I work only with the original designs and specifications.

Question 2: 1963-67 A) Probably as close as Halibrand Engineering could, they made the wheels and racing KOs. Putting machinist dye on one or the other and running them together shows a pretty good broad interaction. B) Depending on car type and wheel type the Shelby race team used nuts with two different size tapers over the 1965-67 time frame that I know of. Lots of factors come into consideration including but may not be limited to wheel design, wheel hub thickness, diametric “size” of the threads, hub length, and how many thread turns were on a given hub.

Question 3: As far as I can tell the aluminum blanks forged by Harvey Aluminum and the forged steel blanks of undetermined origin (which the Halibrand name in each wing) came out in either late 1963 or early 1964. I have not found either part’s original drawings. The Shelby race team previously used small cast steel KOs supplied by Ted Halibrand that had no markings on them except an X-ray inspection approval ink stamp when brand new. The cast steel parts with short arms were not tough enough for the big metal hammers race teams typically used; the arms broke off. I looked at one unrestored Cobra racer with cast steel nuts decades ago with two arms of three missing at one front corner.

Note 1: Over the past few decades several individuals or companies have created aluminum, steel, and stainless steel KOs marked with the Halibrand name. Just having “HALIBRAND” text on a part does not mean it was made by any version of the Halibrand company. Indeed, there are some rather fragile cast aluminum KOs out in public marked as being Halibrand.

Note 2: There are numerous genuine 1960s parts produced by Halibrand around in forged steel and aluminum that have been polished and or polished and chrome plated where the HALIBRAND text was removed during polishing.