Bill,
I just searched for "vernier".
Look for this one:
Repair and Fabrication of a Preselector Vernier Drive
Shows how one guy fixed his which must have looked like yours.
I am guessing that the T-4XC is the same as my T-4X and T-4XB however.
73,
Gary
WB6OGD
On 03/14/2023 10:02 PM Bill Leonard N0CU <billincolo73@...> wrote:
Gary,
Your drive is similar, but noticeably?different. Yours appears to have the bearings enclosed in a shell that I am guessing provides the needed pressure to force the outer (larger) shaft to rotate when the inner shaft is rotated. Mine (see pic below) as open bearings. In the current state, the small shaft rotates but does not cause the bearings to rotate, which means the larger shaft does not rotate (pic was taken with the bearings removed). Does the large shaft on your drive rotate when the small shaft is rotated?
Earlier I referred to crimp pressure. That is probably not the best?way to describe what I was referring to. Inside the large shaft, and at the end of the small shaft there is a spring, which I believe causes the necessary friction to force the ball bearings to rotate. However, it is an extremely stiff spring and I simply cannot get enough force to compress it onto?the shaft that moves the slugs in the coils to the point where I?can set the?Allen screws, so when the small shaft is rotated, nothing happens with the large shaft.
The pdf on the drive repair appears to show encapsulated bearings, similar to your drive.
I tried searching the files section but didn't find the article?you just sent, or any others on vernier drives. What words did you use in your search?
Here is one out of a T-4X.? Is yours like
this?
?Sent from my iPhone
Gary,
I am suspecting that there is a crimp force part to the solution, but if so, I think that the crimp force has to be set with the long shaft attached. That is the shaft that moves the coil slugs. If so, then I wonder if there was a special fixture that Drake used to do it. The reason I say that is as soon as I loosened the Allen set screws, the shafts loosened up and they haven't operated properly since. Hopefully I am not the only one to encounter this problem and that there is a workaround for not having the fixture if one was used.
How about some photos.
The Drake drive is crimped together by the
outside.? Getting the crimp force right is the?
adjustment.
73,
Gary?
WB6OGD?
Surely there is a youtube video on this somewhere?
73, Jim W7RY
On 3/14/2023 4:49 PM, Bill Leonard N0CU wrote:
I was trying to free up the RF Drive by cleaning out the old grease. Made the mistake of loosening the Allen screws. After getting the bearings back in their holes, the small center shaft spins freely without turning the large shaft. I noticed that there is a spring on the end of the small shaft, but I cannot figure out how to get enough tension on the center shaft to get it to spin the outer shaft. What am I missing?
--?
Bill N0CU
--
Thanks and 73, Jim W7RY
Gary WB6OGD