Reichert received and a question

[apochronaut]

You have the inner race of the old bearing do you not? You have the new bearing? Do you have a vernier caliper or some type of inside caliper?
Can you measure the two if them. I mic'ed the i.d. of the inside race of the old bearing I had kept, at exactly .125.

[Stomias]

Getting the old bearing out was destructive. It literally had 3mm chunk of the outer race missing and as I removed i,t it disintegrated. I will try getting that bearing on again as I retrieved the new one from the bowels of the scope. Removing that whole assembly still looks like a pain. If I do it from the bottom I must remove much of the light path to get to it. From the back it could be done but really tight quarters and need a small 90 degree screw driver and I worry about removing that pit on the flange. It is very tiny and disassembling any of this stuff scares me as to the difficulty of getting it all back together and functioning normally. I've been using it the last couple of days and really enjoying it. The focusing is functioning smooth quiet and stable with the teflon tape on that shaft/pin. After having it open (several times) and putting the focuser through its full range of motions and observing it I feel it could function this way a long time without failure. Even with the horribly disfigured original bearing it looks as though no damage was done to the focus flange/cam.

[apochronaut]

Yeah sounds like something wrong. With the adhesive scraped off the shaft measures a couple tenths over 0.124" and the bearing is a smooth slip fit.

A couple of tenths would put it at .324? Don't you mean a couple of thou.? I just got out my 30 year old vernier caliper that I have always regarded as dead accurate. I get .125 dead on for the old inner race that I have kept as a sample. The electronic vernier I bought several years ago gives .124.
The outer race is .317 o.d. and the width .141.

[hans]

Tenths of a mil -- read 0.1242" but I wasn't being that careful and my micrometer technique is probably lacking anyways.

[apochronaut]

Warm the bearing and chill the shaft. There's your mil

[wporter]

Haven't been watching the forum much lately so I missed this thread until now. But I've done this repair before and used these bearings from McMaster-Carr:

Diastar or Microstar 4 focus cam follower: type R2-5-2Z (also known as R2-5-ZZ or Dynaroll Corp. SR2-5ZZ A5), McM-C stock number 57155K366, 440C stainless steel high-precision ball bearing, ABEC5, double-shielded, oil lubricated. 0.1250" x 0.3125" x 0.1406". Made in Japan.

Top guide bearing (#41 on Diastar exploded diagram): type R1-5-2Z, McM-C stock number 57155K364, 3/32" I.D., same specs. I have a note on this bearing that it is also good for the VBX cam, too, but I can't remember what that's about.

[Stomias]

At some point in the future I'll dig in to it again and try the heat/cool trick which I have used in other such endeavors in the past. As of right now I am enjoying the sh%# out of it. Set up a work station and bought more accessories. Waiting on some filters to drop in for DF and Rheinberg illumination. I've found that, as one of our fine members here mentioned earlier in this thread, the amount of focus travel I've used over the last week shows that I needn't worry about this. Coarse focus is set and any fine detail focus is so minute that the travel on the bearing-less shaft on the flange (which has held the teflon tape I put on) is insignificant and smooth without any roughness or backlash/play. All is good.

[apochronaut]

I just bought a pack of 10 sealed 693ZZ bearings from China for 3.17 + free shipping.

Wow, that's $0.31 per bearing. What are the quality of these things? The old saying "you get what you pay for" comes to mind here.

Well, my .31 per bearing pack arrived yesterday. That's 1/86 of what the poster got soaked for and he couldn't get his 26.00/bearing effort to fit. I think the quality of these is quite good. Certainly very similar to the original, sealed and case hardened. I tried a brand new double cut Nicholson needle point Swiss made file on both outer races and both lost nothing, so I think I got what I paid for and considerably more.

[dtsh]

I just bought a pack of 10 sealed 693ZZ bearings from China for 3.17 + free shipping.

Wow, that's $0.31 per bearing. What are the quality of these things? The old saying "you get what you pay for" comes to mind here.

Well, my .31 per bearing pack arrived yesterday. That's 1/86 of what the poster got soaked for and he couldn't get his 26.00/bearing effort to fit. I think the quality of these is quite good. Certainly very similar to the original, sealed and case hardened. I tried a brand new double cut Nicholson needle point Swiss made file on both outer races and both lost nothing, so I think I got what I paid for and considerably more.

Are these perchance the same size as the cam arm or head bearings in the AO10/20?

[apochronaut]

Wow, that's $0.31 per bearing. What are the quality of these things? The old saying "you get what you pay for" comes to mind here.

Well, my .31 per bearing pack arrived yesterday. That's 1/86 of what the poster got soaked for and he couldn't get his 26.00/bearing effort to fit. I think the quality of these is quite good. Certainly very similar to the original, sealed and case hardened. I tried a brand new double cut Nicholson needle point Swiss made file on both outer races and both lost nothing, so I think I got what I paid for and considerably more.

Are these perchance the same size as the cam arm or head bearings in the AO10/20?

No. those are a larger bearing. Never had one of those out but the diameter of the outer race looks closer to 3/8. Those are also unshielded, so can be lubricated with a little injector.