Bearings Type? (Century JJ 70mm Optical Bypass Rollers)

[Ryan Gallagher]

What grade bearings do I need if I want to service/replace in the optical sound 70mm bypass rollers?

Found a couple that are starting to exhibit a little drag.

Existing are stamped SSR-4ZZ manufactured by NMB. There seems to be a lot to choose from in the SSR4ZZ and SR4ZZ line:

https://www.nationalprecision.com/pr...oduct-variants

Looked in all our parts locations, no spares ATM,

[Steve Guttag]

Remember, with Century...nothing is precision. That doesn't mean you can't use precision stuff but it never had it to begin with. ABEC-1 is going to be fine, particularly for something like a bypass roller. If it fits, it works.

[Ryan Gallagher]

Remember, with Century...nothing is precision. That doesn't mean you can't use precision stuff but it never had it to begin with. ABEC-1 is going to be fine, particularly for something like a bypass roller. If it fits, it works.

Thanks Steve. I was rushing out the door when I posted it the Q. I expect the answer is the same... but to use better terms after looking at parts catalog, I'm actually referring to the large and small dia "film guide roller assembly" that are part of the idle/bypass path within the optical reproducer, not the bypass rollers on the external bypass (which we lack).

I also had the thought that maybe some of the 35mm ones in the mag penthouse are the same bearing? I could maybe swap until i can service or replace the issue ones. We have no 35mm mag capacity in our CP200.

I didn't snag a picture, but to steal one from the archive for illustration. Suspect bearings in Yellow. Possibly available bearings in Green (for now).

rollers.png

[Steve Guttag]

I know what you were referring to. Bypass rollers in the optical soundhead are going to be smallish and, again, low-precision. Other than keeping the film from scratching and guiding the film in/out and around things, they don't really do anything precision. The token lip on the rollers are just to keep the film from walking off as the film is under tension from either the take up reel or platter take up. The bearings are going to be small (the diameter of the rollers are small too).

You'll likely find that the rollers that actually are part of the magnetic sound reproduction are going to be more substantial. Everything the film touches between the film stabilizers becomes a potential source for irregularities. No doubt, the "engineers" at Century used the mass of the rollers themselves as a mini-flywheel to reduce flutter introduced by the guidance.

[Ryan Gallagher]

Thanks. We have 70mm Tuesday (tomorrow). Of course one notices these things as I started to reconfigure the projectors last night.

i have some that should arrive this evening, but not overly concerned, they still turn easily, but lack some of the free spin duration like the other projector. I cleaned some buildup off the flanged cap screw faces, which seemed to eliminate the sensation of rough patches.

[Tony Bandiera Jr]

Thanks. We have 70mm Tuesday (tomorrow). Of course one notices these things as I started to reconfigure the projectors last night.

i have some that should arrive this evening, but not overly concerned, they still turn easily, but lack some of the free spin duration like the other projector. I cleaned some buildup off the flanged cap screw faces, which seemed to eliminate the sensation of rough patches.

Ryan, quick and dirty solution:

Remove the rollers and use alcohol (On plastic) or brake cleaner (Metal rollers ONLY, never on plastic) Soak or spray the bearing to get rid of the old grease inside. Gently dry them with canned or compressed air, and relubricate with the same oil you use in the intermittent. Wipe off excess oil on the rollers and you'll be good to go.

[Tony Bandiera Jr]

Remember, with Century...nothing is precision. That doesn't mean you can't use precision stuff but it never had it to begin with. ABEC-1 is going to be fine, particularly for something like a bypass roller. If it fits, it works.

More like the Monees and Cinicitas (Or as I called them, the moanings and Sorry to see ya's) which were beyond horrid. The Centuries I dealt with, while not the greatest, were at least semi-precise. (As long as you didn't interchange gates and traps as they were always wildly different even within similar serial number groups.)

I had one eight plex back in my RCA Service days where I had to engrave and paint screen numbers into each set to keep the booth monkeys from moving them around. (Found out later that each Weds. the head booth monkey would pull ALL of them out, take them to the bench and do a good cleaning on them. Then just throw them back into whatever machine at random. They were generally always clean and the lateral guide rollers always oiled, but....)

[Ryan Gallagher]

Ryan, quick and dirty solution:

Remove the rollers and use alcohol (On plastic) or brake cleaner (Metal rollers ONLY, never on plastic) Soak or spray the bearing to get rid of the old grease inside. Gently dry them with canned or compressed air, and relubricate with the same oil you use in the intermittent. Wipe off excess oil on the rollers and you'll be good to go.

Thanks Tony. I would assume with how smooth and long spinning these are when healthy that they are light-oil bearings anyway. Just no break cleaner or diesel in our booth at the moment. I have 99% ISO though. CRC Contact cleaner might be the closest solvent I have. The ones I ordered in a pinch probably are not light oil versions... so may have to go through the quick and dirty approach anyway.

[Ryan Gallagher]

Although of course my bearings arrived after I left the house today... but Tony's suggestion of just flushing and oiling them did the trick. I took a gamble with the CRC contact cleaner... but it did the trick... saw the fluid become discolored as it flushed all the old oil/grease out. Sprayed dry with air duster, light application of intermittent oil got them running like butter again.

Only did the worse of the two, the one that wouldn't turn under the weight of a loop of film with no take up tension.