> From: Don Malling
> Sent: Wednesday, September 07, 2005 9:35 PM
>
> What are the list's thoughts about welding the
> clutch fork to the cross shaft. Will I have to
> cut the shaft to remove/replace the clutch
> release bearing if I weld it? Seems for the cost
> of a shaft and release fork it's an easy and sure
> way out of the broken pin problem -- pulling the
> transmission etc.
Here is another gem I saved from Brian Schlorff (Power British) when I used
to subscribe to the big triumphs list:
>>>>> start <<<<<
The fundamental engineering problem with the clutch fork is simply this:
The pin is tapered.
The cross-shaft has a tapered hole to accept the tapered pin.
The partially threaded bore in the fork IS NOT TAPERED!!!
What this means is that contact is made on only one side of the fork pin.
(the side nearest the threaded portion just below the head) All the force
is concentrated at that spot and the pin will ALWAYS break at this spot -
never anywhere else. The best, albeit not so easy, solution is to ream the
hole in the cross-shaft to the same diameter as the bore in the deepest part
of the fork. Then fabricate a new pin, one with a straight shank of
corresponding diameter + .001" for an interference fit that will tightly
engage both sides of the fork. No modifications are made to the fork, but
now the shear force is divided equally between the top and bottom of the new
pin, which is also slightly larger in diameter than the original tapered
pin.
The real benefit comes from the fact that the topmost portion of the pin
extends directly up into the right-hand finger of the fork, thus there is no
chance of overstressing or cracking the base of the fork around the shaft.
I know it is not exactly a do-it-yourself prospect to make such a set up,
but we feel this is the best way to insure never having to do that job
twice! :-)
>>>>> end <<<<<
Peter Zaborski -- CF58310 UO
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