Sunday, May 22, 2016

Wheel finished and beginning reassembly in 1442 Card Reader/Punch


I received the grit and did a test slurry. I discovered several things from the test. First, medium grit (1/4 millimeter) is way too coarse to match the original ceramic grit, but fine grit, about a tenth of a millimeter diameter, is a great match. Second, mixing the grit with the glue first produces unsatisfactory results.

My second try was much more successful. I used fine grit, put a thin layer of adhesive on the wheel and poured the grit atop it. I tamped it down slightly with my finger and then cured the adhesive with UV light. I have a couple of small sections that are too bare, but most of the wheel surface is already good. Later I will try to fill in the sections without raising the surface too much.

repair in process - bottom wheel, left side original, right is repair
I also have a high spot near the join with the original ceramic. I will carefully grind it down and if too much grit is lost, dig it even lower and add adhesive plus grit to relevel. I feel good about this process and should be able to finesse this into suitable condition.

Wheel damage before I filled and began restoration
Sunday morning saw the completion of the wheel. I smoothed and filled in the top surface, have enough grit to ensure a great grip on the punched card stock as it is moved through the punch station. I decided to add some grit to the sides of the wheel, since cosmetically the clear adhesive in the repaired section was noticeable. I didn't fuss with exact fit or appearance, so that the sides are a bit more patchy, but overall the wheel is ready for re-installation, once I flow off any remaining lost grit especially near bearings and turning surfaces.

Wheel ready for final cleaning and then installation
The part is cleaned and reassembly is starting as of Sunday night. I have a table set up with the parts and relevant parts and maint manuals, so that I can fit it all together. Monday's the day.

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