from: Grant Saviers
to: 1401 Restoration Team
date/time 7/24/2004 12:22 PM

subj:  more on corrosion , bearings, & rollers in the 1402

All,

I spent some time Thursday looking at the 1402 mechanism and have the 
following observations and recommendations:

Overall, I think the mechanism is in ok functional shape from a 
rust/corrosion perspective.  It may not look great, but I think there 
are more pressing problems in achieving full mechanical function and 
durability.

I identified three areas of significant concern to the mechanical 
restoration:

1. Almost all of the timing belts (they are numerous ~ at least a dozen) 
are cracked and dry rotted.  They may work for a brief time but will 
likely quickly fail.
2. I rotated a couple of ball bearings by hand and they exhibited the 
usual problems of dry grease - very lumpy rotation which can be reduced 
with repeated back and forth working.  This means that the oil in the 
grease carrier has mostly evaporated or migrated elsewhere and the 
carrier of the oil has congealed/hardened into lumps.  It is difficult 
to see the type of seals on some of the bearings, but many appeared to 
be metal shields which makes oil injection or grease replacement almost 
impossible.   Again, they may work for a brief period but without fresh 
oil/grease it  won't be long until they fail.
3. Rubber rollers look ok but I had no way to verify that the durometer 
of the rubber was as soft as it should be.  Most likely all have 
hardened with age.

Solutions?

1. Assuming IBM used industry standard sizes (pitch primarily) for 
timing belts, we should be able to make or buy replacements for them.  
Otherwise we have to replace the timing belt pulleys with standard pitch 
sizes.
2. Bearings are a nastier problem.  They are almost certainly industry 
standard sizes as even IBM would be reluctant to special tool for them.  
Replacements should not be too difficult to find or very expensive as I 
would bet on no area in a 1402 that would require a high grade (ABEC7 or 
9) bearing of the type used in disk drive spindles.  However, replacing 
all of the bearings is a monumental job and we may get into areas 
requiring special assembly fixtures.  As the card reader side is 
considerably simpler than the punch, perhaps we should start there.  A 
comment was made at the kickoff meeting by an IBMer working on the 
RAMAC(?) restoration that "they gave up and decided to replace all 
bearings".  Could the participants in this restoration weigh in with 
some advice?
3. A comment was made by the previous owners of this machine that they 
had devised ways to make new rollers.  We should find out which ones and 
how.  Fabrication on new rubber tires may not be too difficult if we can 
find the original engineering specifications (material, durometer, 
finished dimensions).   Can IBM provide us with the engineering print 
sets from their archives for all of the equipment?  (Robert -can you check?)

I think that most of the work in the short term should focus on a 
thorough cleaning of the mechanism, as there is a large amount of card 
dust and other debris adhering everywhere.  Here is what I would 
recommend as a process:

1. Thoroughly clean every area that can be accessed, starting with short 
nylon or fiber bristle brushes and a vacuum cleaner with a HEPA filter 
(no sense in just moving the dirt around in the room).
2. Wipe down all surfaces with dry Kimwipes of a non linting type.  
Remove grease that has migrated from the bearings.
3. Clean all functional surfaces with a mild solvent wipe - e.g. alcohol.
4. Remove any parts that have corrosion which we think will adversely 
affect operation and clean them as outlined earlier. Re-install.
5. Identify all timing belts, pitch, width, length and find replacements.
6. Identify all bearings and determine the feasibility of replacement.  
(again engineering prints would be super helpful for #5 & 6)
7. Decide on a course of action for bearings and rollers - there are 
some grease fittings in the machine so these bearings may not need much 
more than fresh grease, but there are many that are sealed.  WE SHOULD 
NOT RUN THE MACHINE PRIOR TO A CAREFUL ASSESSMENT AND PRECONDITIONING 
EVEN IF WE DECIDE TO "GO FOR IT" WITH THE CURRENT BEARINGS.

Another possibility is that there are spare parts sources for a 1402 
somewhere in the world.  Dag advised we should pass on some card 
equipment on ebay this week as "there are plenty still around".  Any 
thoughts?

regards,

Grant