If we use the big part of the sun gear as a male spline on the female billet coupling  this will greatly simplify the input shaft. This part of the sun gear is normally ground down and not used.

Still a work in progress.

Paul Lamar

I suspect machining a spiral or helical female  spline might be a real problem. So extended point set screws to the rescue.

This is major simplification and addresses a problem we have had in the past with the pin joint failing between input shaft and sun gear.

It also does away with one more spline eliminating all back lash from that source.


Paul Lamar


Paul,
How are you going to ensure that the set screws will seat down between the teeth on the sun gear ?
I see that the holes for the set screws are parallel with the axis of the input shaft whereas the teeth are not.
If the set screw tip coincides with the tip of the tooth it will be virtually useless.
Chris.


I thought about it some more and I am going to cut the teeth off the sun gear the way we do it now. That will reduce the diameter of the coupling and the helical gear thrust needle bearings. That will extend the life of the thrust needle bearings. It will be easier on the oil seal as well. I'll up load the new 3D's tomorrow.


If this works it will be the first real gear box  improvement in 20 years :)

Paul Lamar

Here they are.

-----------------------------------------------------------------------------

This is for the 3.12 version. On the 2.85 the coupling is even smaller.

Get a small bench grinder and mount it on the tool post holder of your lathe and you can grind the teeth off the part of the sun gear in question.

BTW this torque isolator is not a new idea. It is widely used on off road motor cycles.

Paul Lamar



Hi Paul,
I put my sun gear in the chuck and used an angle grinder to grind
off the teeth, it is MUCH faster. When the teeth are gone you can finish off, turning with a
normal cobalt tool.
Cheers Chris. in NZ

Morning Chris.

Now you have two ways to go. You can use the old fashion way and pin it to
a 1.5 inch OD Ford input shaft. Yoiu will need two pins. Then come up with a female spline
plate to bolt to a rubber  coupling.

New way.
Find some one to mill a female  billet coupling and use extended point set screws on the OD of
the sun gear. Much stronger. No spline slop and cheaper overall.


Here are some pictures of the Tracy Crook  old way.
The input shaft and the spline plate are cut down Ford auto tranny parts.


Paul Lamar


A good plan is after the coupling is machined but before threading the holes for the set screws is to get the pieces set up where their final position will be. Then drill small countersinks for the set screws to sit in. The angle on the end of the drill that just fits the thread holes is probably good enough and 1/8" deep. If the coupling is a hand press fit to keep things centered the countersinks will help prevent any possible slippage.

Dale Davies


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