Indicator Repair

I scored a lot of ten Mitutoyo dial indicators on eBay for a song - a mix of 1um and .01mm. The lot was listed as 'for parts or repair.' All were filthy, most were sticky, some had missing crystals, and one was missing its back cover.

I started by disassembling the indicators and cleaning them up. I put all of the mechanical internals through my ultrasonic cleaner, one indicator at a time. The ultrasonic is filled with water, but the parts go into a jar full of naptha. The faces and bezel rings were washed by hand, using a q-tip, dish soap, and water.

The indicators were carefully reassembled. They are not that daunting - especially compared to modifying a wrist watch. A few had some worn or damaged internal parts, but I was able to find replacements. I ordered the missing back, plus a set of new crystals and gaskets. The crystals were shrunk for installation using dies from my wrist watch crystal press used in my bench vise. I 3d printed some new bezels to replace the worst of the damaged ones.

All ten were brought back to working order, but I now had a new problem - what am I going to do with ten indicators?

I planned some future projects - a mill tramming tool would use two, a set of dial depth gauges would use another three, and maybe a squareness comparator and a tool height presetter. I'm sure I'll find some other uses when I get a lathe, like a center height tool and an indicator stop.

I decided to make some custom dials and bezel rings for specific purposes. Most indicator rings at the 1um scale are used for comparing parts, not for measuring, so the bezel ring approaches 0 from both directions, rather than counting in a full circle.

For the depth indicators, I actually needed the indicators to count in reverse - e.g., how far the stem extends out, not how far it is pushed in.

Rather than use the originals, I machined some new bezel rings and faces on my CNC using some thin aluminum sheet and a 1mm end mill. The faces themselves are printed on vinyl sticker paper using my laser printer. I designed the new faces in Inkscape.