I am really puzzled now. After closer inspection I am back to having no idea how the preload is set. My initial thought of getting the allen screws into the groove on the main shaft while compressing the spring isn't the answer.That connects the two shafts but it doesn't provide?any preload. It looks like Gary's vernier?would?work since it appears from the pic that the preload on the bearings results from the way they are encapsulated in the shell and the set screws simply attached to the main shaft. If I can locate one like that, do all T-4xx verniers work in all T-4xx transmitters?
On Wed, Mar 15, 2023 at 9:59?AM Bill Leonard N0CU via <billincolo73= [email protected]> wrote: Gary & Steve,
Gary,
1) The 1st pic I sent is the drive disassembled. However,
the only parts missing in the pic are the bearings and
the Allen set screws. Compared to your drive, it does look like it is missing a
cover, however, this style drive does not have the bearings encapsulated.
I just remembered that my R4-C has the same style drive. I
attached a pic to show how it looks fully assembled. This drive is working
fine. I was able to clean the bearings without loosening the set screws so I didn¡¯t
encounter the problem that I am having with the T-4XC drive.
2) The link to the article you referenced no longer works.
The post was from K4OAH (SK). The only info on his website now addresses the service
CD his wife still sells.
3) I figured out what I did wrong with my search of the files
section. I looked over all 184 posts that have the word ¡°vernier¡± and the only
ones that looked like they addressed my problem were also from K4OAH and the
attachments he referenced are no longer shown.
4) The spring is not a work around. It
is what puts the preload on the shafts and bearings so that the small shaft
will turn the large shaft.
Steve,
Since the drive in my R4-C is identical to the one in my
T-4XC, I don¡¯t believe that this one has been worked on. I agree that since
the bearings are unencapsulated, there needs to be a preload to get the
bearings pressed against the race, however, the spring that creates that preload
is so strong that simply pushing against the shaft hardly moves anything. There
needs to be enough force to compress the spring enough so that the set screws
will reach the groove in the main shaft, which is what retains the pre-load on
the entire assembly. I suspect that Drake had some fixture which allowed the
necessary force to be generated. However, this preload needs to be generated with the long shaft (the?one?that moves?the slugs in the coils) attached to the drive since that is the shaft that has the groove which maintains the preload after the Allen screws have been tightened. Where I am stuck is trying to come up with a way to generate the necessary pressure on the spring so that I can tighten the Allen screws. Thanks to both of you for your assistance!
On Wed, Mar 15, 2023 at 6:19?AM Steve Wedge, W1ES/4 via <w1es= [email protected]> wrote: That drive looks like it has been worked on before and not properly reassembled. There should be a second part that covers the bearings like in the first photo.
These drives also need a pre-loading, which is why the mounting shaft appears to be at a non 90¡ã angle. The bearings must be pressed against the race for the drive to work.?
73,
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
Sent from Proton Mail for iOS
On Tue, Mar 14, 2023 at 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?  ? 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
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