After 5 years of use, my Park Dial Indicators (Park TS-2Di) started to show their age. They no longer moved smoothly across the range, but jerky and the dial shaft would stick. This would cause incorrect roundness or trueness readings. I had to replace them.  When I started looking into precision dial indicators, a Japanese brand Mitutoyo kept coming up in reference to a solid, high quality dial indicator brand.  I had been over to Ryan Kereliuk’s shop (spokeservice.ca) to check out his Morizumi SCT spoke cutting and threading machine that he’s had for awhile now, purchased from Ric at Wheel Fanatyk. Ryan and I share some common interests, including both being in the information technology industry and both having a passion for building quality hand built wheels using quality tools and repeatable, quantified methods. When I was there, I noticed he had hacked his 2Di dial indicator mounts, replacing the low-quality Park dial indicators with high precision digital dial indicators from Mitutoyo.

Like a tachometer or speedometer in a vehicle, I knew I wanted to stay with analog dial indicators over modern digital, as I can visually compare the rate of movement from one measurement to another, and better predict the adjustments required. Digital just doesn’t allow for that interpolative intuition.

After a bit of research online, I settled on the Mitotoyo 2048S dial indicator. It’s minimum measure was 0.01mm – the same as the Park Tool, and the unit is manufactured with the quality and precision of a fine mechanical watch.   The back plate has the same bolt mount point that the Park dial indicators have, so replacing the 2Di indicators would be relatively easy.

In order to let the new dial indicator reach the rim for roundness, while simultaneously allowing the trueness dial indicator to align to the rim, I had to fabricate a custom extension rod from 1/2″ aluminum rod stock. The Park dial indictor used for roundness measurements had a bulky extension and roller glide that provided the necessary reach. I think this extension is what shortened the life of the dial indicator as it added extra weight to the indicator’s plunger springs and likely caused inaccuracies too.

The end result is a dial indicator solution that retains the best of the Park Tool 2Di indicator set – the mounting hardware, but adds the precision and durability of the Mitotoyo 2048S dial indicators.

 

 

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