Torque Tube coupler Pin Questions

[19Fordy]

Still working on my rear end so I can install the special oil seal to prevent rear end gear oil from running down inside the torque tube. I heated the head of the pin to cheery red and proceeded to hammer it to form a head as there was no head formed back in 1940. Let it cool down and quickly discovered (with a smooth file) that the end of the pin had become as hard as glass. Could not center punch it or drill it. Plus the pin now had a head but had become loose. Chiseled (chipped) top of it away and was able to drive the pin out. The pin measures .251 in. dia.
I wonder if that pin was made of air hardened tool steel and why did it loosen?

QUESTIONS:
1. Where is the best place to purchase two new pins?
2. Any special procedure to follow when installing the new pin
and forming the head?
THANK YOU.

[G.M.]

I had a few pins come loose over the years and replaced them with roll pins.
These are spiral wound pins made of spring steel that comes in a assortment
of diameters and lengths. I would find a size a few thousandths larger and ream
the coupling out so it has the correct fit. Use high strength lock tight and drive
it in. It don't need to be penned over at the end if it drives in good. G.M.

[V8COOPMAN]

Jim......I would not use a HARDENED pin, such as a Grade 8 type bolt. You know that a hardened pin can shear much more easily than a soft pin. Fact is that the pin should serve no other purpose than to locate the coupler.......to keep it from moving fore and aft. The pin should bear NO torsional load. If your splines are nice and tight, you should have no problem with fitting a softer bolt shank that is a snug fit. I would then peen both ends over. I would NEVER leave a pin UN-peened under any circumstances, even if it fits tightly AND is set with Lock-Tite.......PEEN it both sides! And don't forget to properly support the coupling when peening the ends of the pin. DD

[19Fordy]

GM: Using split pin scares me a little. + Are they really tight enough so as not to slide out due to vibration?
V8: I think the reason the OEM pin loosened after I tried to form the head was because I did not have the other end of the pin "backed up" with a solid block of steel. Therefore, I actually drove the original pin downward while forming the new head. Your fore and aft movement theory makes sense. Got to find a grade 5 1/4 in. bolt with a "fat" shank. Perhaps a galvanized bolt will work. Oh for the days when I had a lathe.

[rotorwrench]

The pins are P/N 68-4607 and are available from most suppliers. There are some lightly corroded NOS ones on flea-pay.

[19Fordy]

Sponsored Links (Register now to hide all advertisements)

Rotorwrench: Thanks. Those Ebay price are ridiculous. Found other vendors cheaper.
Will probably make my own.

[rotorwrench]

That light countersink in there complicates things a bit in trying to form a head. Bolts are likely harder than those rivets and will not squish easily like they should. I think I'd buy the ones on flea-pay or other sources as you see fit. I use a big 5X rivet hammer to drive these type of things. Beating them with a regular hammer can be a pain in more way than one. In any case, choose a large heavy bucking bar and prop it over some heavy structure like a concrete block or use an anvil if you have one. You want to squish that fastener down into the bore to get it good and tight. If it is loose at all it will shear more quickly. You need at least 1 & 1/2 the diameter of the rivet above the surface of the bore. If you go much more than that they will sometimes try to bend over on you. The OEMs are 1.7 inch long if I remember correctly.

[19Fordy]

"O - key, dough - key." Thank you.

Would it be OK to make a rivet from a bolt by heating it until it's cheery red and letting it air cool? That would anneal the metal and make it more malleable.Then cut it to 1.7 , hammer it in and then form the rivet heads.

[glennpm]

You could do it that way if you held it vertically away from the 1.7" so everything air cooled the same. Don't lay it down on a piece of steel for example. What about the diameter though and why take a chance?

Joe's Antique Auto (also reasonable shipping. I'm just a satisfied customer of his BTW)

68-4607 Drive shaft pin 1.70” long ** ......... 37-48 1.00 ea

[cmbrucew]

40
If you have a source to get a common nail size 60d it is 0.256" in diameter, and about 5" long. They would be made of nice soft iron, most likely in Wheeling, West Virginia USA

[rotorwrench]

It helps if they are heat treated but bolts are likely made from a different carbon content of steel than those rivets. Annealing them might make them softer but I don't know to what degree. The rivet process sort of forge forms the metal into a tighter bond grain similar to a drop forging process when you form it so it can start out with a lighter carbon content and then be work hardened to a higher hardness level. The longer you beat on it, the harder it gets. Bolts have to start out at a particular hardness level for their strength. Different grade bolts have different hardness levels in their steel composition. They may also have other additives such as chrome, vanadium, or molybdenum to make them stronger. A bolt has to be able to stretch and a rivet doesn't.

[woodiewagon46]

Use the pin that is available from any antique Ford supplier. Don't use a roll pin or a nail. Use the correct pin, too much work to replace if it shears.

[RobR'35]

Anyone else have pros or cons on the aftermarket pins with the strip of spring steel strap that captures and holds the pin in place?
These came as a small kit with a coil spring too that went between the u joint and the speedometer drive gear.

[GEOFFNZ]

As stated there should be no loading on the pin if all the splines are in good order.If you are worried about pin shearing just grind a shallow slot around the outside of the sleeve covering the pin holes and through the riveted pin heads and install a safety wire.Have pulled one apart that this had been done to and sheared pin was still captured.Cheers.

[RobR'35]

Interesting idea. Thanks

[rotorwrench]

The spring steel keeps it from coming out when it breaks. It generally won't fracture unless it comes loose. Bolts are already a slip fit by design so they are basically already loose. Worn splines invite fractures even if you drive the rivet pins in solid.

In aviation we use expandable bolts for stuff like this. Each main rotor blade is held on an MD 500 type helicopter with two of those cam/lever locking pins. The overall diameter of the pins are 3/8 inch but the inner core expander bolt is only 5/32 inch diameter. They are life limited and generally last their full life unless they are in a corrosive environment. We pull them out and inspect them on each 100-hour inspection. They are likely to expensive too be used on an old Ford.

[PeteVS]

Way back at work, we had an older engineering manager who wouldn't allow "roll" pins to be used in our designs. We did, however, often use "spirol" pins. They're like a roll pin, but they're multiple thicknesses of material. McMaster has them.

https://www.mcmaster.com/#standard-spring-pins/=16p6tlb

[glennpm]

So what did you end up doing .... ?

[Kube]

Originally Posted by woodiewagon46

Use the pin that is available from any antique Ford supplier. Don't use a roll pin or a nail. Use the correct pin, too much work to replace if it shears.

If that pin shears there are more serious issues than the pin itself.

[19Fordy]

Originally Posted by glennpm

So what did you end up doing .... ?

Glenn, I am still debating. Don't know why, but I am hung up on making and installing my own pin. It's just a personal challenge I am fixated on. Today I bought a 1/4-20x2 galvanized hex bolt. The zinc coating makes them about .252 inch in dia. The hole is .250. I would then cut the bolt to the needed length and rethread the end to 1/4-28. The new 1/4-28 threads would be cut on the shank of the 2 inch bolt. Then hammer it into the coupler and drive shaft and secure it with a 1/4-28 nut and locktite. Then cut the threads off about 1/8 in. above the nut and peen it down over the nut. The splines on the coupler and drive shaft are in perfect condition and nice and tight with no play. Plus the other OEM pin hasn't been removed and won't be.
Decision still pending.