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Rust on the IBM 1402 Reader/Punch
Report # 1 by Grant Saviers
The large photos below (accessed by clicking on the thumb-nail sized photo) are 2/3 the edge length of the originals supplied by Grant and considerably reduced in .jpg resolution. For originials (about 350 k bytes each) contact Grant Saviers or me (firstname.lastname@example.org) giving picture name.
All text and photos below by Grant Saviers.
1. 1402 CPPA orig cond - as removed from 1402 card punch assembly. Note: the shaft end bearings are backwards
2. 1402 CPPA shaft - note rust, which is cosmetic, not functional. Also note red marker "witness" marks on the arms and shaft - somebody has had this assembly apart before us!
3. 1402 CPPA arms - same red "witness" marks, probably not accurate enough and can be easily removed. A fine scratch would be better
4. 1402 CPPA pick shoe - lots of cosmetic rust, the other side is the business end with carbide inserts and looks ok. These will be measured in phase 2.
5. 1402 CPPA cam follower - lots of card dust amalgamated with oil & grease. The cam follower bearings are hard to turn.
6. 1402 CPPA cam follower brg - dry brushed to remove gunk, surface corrosion and grime is visible
7. 1402 CPPA cam bearing clip - fortunately, the shaft is not pressed in - is cleaning this area an infrequent PM?
8. 1402 CPPA cam arm dirty - note the packed gunk which jams the bearing
9. 1402 CPPA cam arm spacer - some scraping out of gunk reveals a shaft spacer (small washer)
10. 1402 CPPA arm bearing - this bearing is a cam follower; note the thickness of the outer race, designed to prevent its distortion from the cam pressure. The bearing is MRC double sealed type R-B/8-F/P-F/P-P/R-8/B (each digit is most likely character/alternate) or most likely RBFFP8. The id is stamped into the rubber seals on both sides of the bearing and difficult to read, even under moderate magnification. The dimensions are .187" id x .625" od x .195" width. Since this is a sealed bearing I used a little steel wool to clean up the outer race surface. It appears to be ok functionally and turns very easily.
11. 1402 CPPA arm shaft - the cam follower shaft shows an unusual wear pattern of repeating diamonds. No dimensional differences could be detected with a dial caliper.
12. 1402 CPPA end bearing - backwards on the shaft again. Note the screwdriver "oops" (ding) probably inflicted in the disassembly. A better tool would have prevented this. Should be easily fixed with a little filing.
13. 1402 CPPA end bearing detail 1 - dirty, but mostly gunk and a little cosmetic rust. The bearing type is SKF double shielded, marked 393214, dimensions .375" id x .875" od x .250"? width (I could not measure it directly without removal). The shields are the pressed in type, not removable without destruction. The bearings (both ends) turn freely.
14. 1402 CPPA end bearing detail 2 - other side of detail 1. Not sure of the engineering function of the rubber damper/seal/??. Anyway, it is coated with a different kind of gunk, semi-transparent dry grease, assembly adhesive, or ?
15. 1402 CPPA end bearing parts - careful prying and massaging by hand separated the rubber inner part from the two sleeves. The rubber part is a soft durometer and in good shape, no cracks, tears etc. It went back together easily. Again, what is the function?? I don't want to clean it until some light on this issue and an idea of the composition for solvent resistance, etc.
16. 1402 CPPA cam arm cleaned - a soft brush and some paint thinner made it look new. Note one bearing spacer for the cam follower bearing. This shaft had one, the other shaft two spacers, one each side of bearing. Again, SOMEBODY HAS BEEN HERE BEFORE ME! There should be two spacers, since the bearing inner race is the same width as the outer race. The spacer keeps the outer race from rubbing on the side of the arm. A slight wear pattern is visible on the arm side without a spacer. The spacer is 0.020" thick x .187" id x .375" od, probably steel as there is some surface corrosion present. I need to make a replacement for the missing spacer and install it.
17. 1402 CPPA detail cleaned - I didn't loosen any of the cam follower or pick shoe arms as I saw no need. With a new spacer I think these parts will work ok and the bearings seem to be in very good shape.
18. 1402 CPPA clean - Further action on this part is a. cosmetic (except needed spacer) and optional and b. measure the pick shoe steps for wear
19. 1402 CPPA tools - nothing fancy hand tools, a magnifying visor and dial caliper. The follower bearing shaft did not need a press to remove.
Overall conclusions and lessons learned:
- Interestingly, IBM chose inch standard bearings for this unit. Metric standards are much more common. Further research is needed to verify replacements are available. The bearings seem to be in good shape, the main functional problem was gunk jamming them.
- More care/right tools need to be used for disassembly to prevent damage (end bearing holder screwdriver ding)
- Even though the team indicated this level of disassembly was not done in the field, this unit has been apart before and a spacer was lost. Note the witness marks, certainly not the accuracy needed by the factory! Lesson - make no assumptions about what we have - look carefully, think about the mechanical design, and proceed with caution and copious notes. (and patience!)
- Further investigation is needed to understand the end bearing assembly functions.
- A standard and index for identifying photos might be a good idea.
- Time involved in this project 1.5 hours work, incl photos. 2.0 hours for report. Camera: Nikon Coolpix 880, 3.3 megapixel, used XGA normal resolution.
- Remove the pick shoes and measure the wear on the carbide (not easy).
- Clean end bearing assembly when understood better.
- Decide if a light cosmetic cleanup should be done.
- As usual, comments, feedback, and all suggestions/help welcome.