Pin drive bolts splitting Help Please

[Dominik]

Dear David!

Thanks for your help. Everything here in SA is closed down, but I can get a drawing from CAV in a week or so, as well as information how deep Wheelcraft/WAW in Pretoria (Vintage) drills the wheels.

I am afraid, that the wheel stud is too long to accommodate a machined nut with hex head and not bottom out when tightened (or the nut now too long to sit inside the wheel)

The CAV GT40 studs could be shorter in the first place, because they are made up.
Possibly the stud diameter of 3/4" allows for a 1/2" thread and a 5/8" hex? That can be checked in CAD quickly.

Cutting the existing studs is possible, but a pain. Expect to wear out one speed grinder disk per wheel (5 studs). And now they are too short in case someone wants to fit 5-lug rims...
Nevermind restoring the thread.

I get the needed information soon and with the help of the forum we can find a solution. Just now I don't have a car or wheel&adapters here to take measurements.

The original/Kirkham version cannot be used for the bolt-on adapter unless we press out the stud, which is not manageable at home. And then we need enough clearance to add a nut to hold the (3/4") stud behind the hub.

Rick did extensive research to make his version work and surely can assist more than me right now.

Dom

[David Kirkham]

No problem. Happy to help.

I'll wait for a pin or a drawing to show up and then we will see what we can figure out.

David

[Dominik]

Ok David.

As for you stud, I agree, having used a similar version for my Contemporary rear hub in 1993. They were screwed straight into the hub as the ones from ERA (?). Made from "tool" steel (can't remember the specs)

I found measurements from Wheelcraft. Their hole diameter is 19.7mm =.775" (!), depth varies from 11/16" to 1 1/4", which is a problem.

LMH's 1-3/16" sounds feasible. That length sounds familiar to my TRIGOs once.

You should ask at SPF and the other big manufacturers to confirm nut lengths and taper angle of the adapter. The adapter is typically 3/8" thick.

Dom

[David Kirkham]

Is this what you guys are talking about???

I had somewhere in the dark recesses of my memory that Lynn Park had sent some of these to us years ago. I just went on an Indian Jones excavation and dug them up. I will look into a way to make these better. It doesn't look too difficult. Looks pretty simple actually.

David

[Rick Parker]

YES David! Those are the later design. The earlier ones used an internal 6 sided hex.

[David Kirkham]

Does anyone know how much they currently cost? I'll try to keep the cost reasonable.

David

[Blas]

David...So you're good to go...I just spent 2 hours looking for my spare Trigo pins...end result, my garage is now clean, my tool boxes are in order and garbage cans filled with junk....hahahaha...my wife says thanks....and now wants you to tell me to look for something in my office...hahahahaha....
FYI...the pins were $6 each when I purchased my spares....

[David Kirkham]

Sounds like you look for lost items like I do. I just start cleaning until it shows up!

Price sounds reasonable. I will go to work and see what I can come up with.

David

[Dominik]

Yes, that is one of Lynn's (Trigo's) design.

Check their taper and if they are concentric. If not, improve it :-)

I would prefer a hex head (5/8"), if possible. It would not crack. A 1/2" thread in a 3/4" material would leave 1/8" of wall (?).

If I remember correctly, they once were $2 each. But $6 would be reasonable.
Anybody remembers wheels not coming off?

The taper is not needed, if the adapter is centered on the hub. However, most adapters come with a taper seat for the studs. Not the later ones from Vintage, though.

Dom

[LMH]

David
My Trigo pins look exactly as the photo you posted. I am not using my wheels at the moment, so if you need pins, I can send you mine. (or a studed hub from a Mustang too)
Let me know if I can help.
larry

[David Kirkham]

Dom,

Isn't it a little late in South Africa?

I think the only way to improve a nut that is not concentric is to see if it floats next to a Great White.

Bummer deal they are all not the same. I'll need to make and stock different programs.

I'll get right back with you. We are making the CAD drawing right now.

David

[David Kirkham]

How does this look guys?

Interestingly, the taper is 82 degrees. We can make them flat as well.

The hex on top is 11/16." We wanted to keep everything as strong as possible. The hex is 1/4" tall. It should work really well.

[LMH]

Looks like it would work to me. I think Vintage wheels uses a similar design.
Larry

[David Kirkham]

We will have some ready next week. Anyone who is interested let me know. The price is somewhat dependent on how many we make. You don't have to commit until I get the final price. The specialty steel place was closed today so I couldn't get pricing on the stainless. It is much more expensive in the smaller diameters and WAY more expensive than chromoly.

David

[Rick Parker]

82 Degrees......is that a normal engineering angle for such an item of that diameter (?) I was thinking 60 degrees would be more common.

[David Kirkham]

Originally Posted by Rick Parker

82 Degrees......is that a normal engineering angle for such an item?

Whether or not it is normal for THESE pins I can't say. However, 82 degrees is a standard counter bore for flat socket head cap screws and other items. Now, does that match the bore in the hub adapters...??? Who knows? I'd need an adapter to measure.

David

[cdnus]

David,
went out to the shop & dug up a spare new Vintage nut & gave a quick measure.
Taper-60 deg.
Overall length-.850
Dia-.750
Staight length ?-.735
Broached hex-12mm.-internal
Thread size-1/2"X20tpi.
Wheel hole depth-.750-.800

If these were made with a 1/4" tall hex-external, that would leave approx. 1/2" of purchase area in the wheel, would that be suffient?

Thanks Craig

[David Kirkham]

Craig,

I am surprised the Vintage wheels won't fit over a Trigo rim???

The Trigo unit is 1 inch tall (not counting the taper) so with a 1/4 hex it would be 3/4" of engagement which is fine. The overall length of the Trigo is 1.188 inches.

We have 1/2" of engagement on our cars + 0.3 inches of lead-in taper. The thread on the hub is a 1/8 pitch so that means you would have to have the knock off back off 4 complete revolutions before the flat part of our pin didn't engage any more. With a knock off that far backed off, I would think you would certainly both hear and feel something. Remember, with these cars, if something feels funny, IT PROBABLY IS!

Hopefully, everyone checks their knock offs BEFORE they drive down the road and not when they see their wheel passing them by on the freeway.

I would imagine if the Trigo units are 1 inch long (not counting the taper) then for the Vintage wheels are probably counter bored deep enough to accept the Trigo units--though someone would certainly need to check this.

Perhaps we could just make the Vintage (flat-bottomed pins) a little longer to make up for the difference.

David

[cdnus]

David,
I had checked for some reason a while ago how much material was left in the rim at the bottom of the holes & it didn't seem like much was there. I phoned Bob & he confirmed that they cannot be deepened for fear of breaking through the front.
So mine at least are limited to a total length of approx .750".
Someone with a different backspacing may have deeper holes, but I believe Vintage only supplies 1 style of nut regardless. I am unaware if they have changed to a non-tapered ( flat bottom) style of nut.

Thanks Craig

[Dominik]

David, you said:
"...so with a 1/4 hex it would be 3/4" of engagement (of thread) which is fine."

The thread must go all the way through, else you "bottom out" when fitting the nuts.
The wheel stud is too long!

And that the taper have different angles doesn't help either...

Yes, it was 1:30am, now it's 8am. I do the float test later - with red wine!

Dom