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Gauge Block Set Oiling

Ray’s Rule of Precision:

Measure with a micrometer. Mark with chalk. Cut with an axe.

While pondering the problem of having the Sherline’s Z-axis anti-backlash nut unscrew at the top of its travel, I excavated the gauge block set and measured the gap between it and the bearing preload nut:

Sherline Z-axis leadscrew nut - gauge block

Sherline Z-axis leadscrew nut – gauge block

Turns out that it’s 0.1340 inches, determined by bracketing the sliver above that 0.1300 block with feeler gauges. I don’t believe that last zero, either, as the Basement Shop was about 10 °F below the block’s 68 °F calibration temperature.  [grin]

The actual size of that gap makes absolutely no difference whatsoever, but fooling around with the gauge blocks gave me an excuse to renew my acquaintance with them and, en passant, massage some oil over their long-neglected bodies:

Gauge block set

Gauge block set

I used La Perle Clock Oil, which isn’t Official Gauge Block Oil, but doesn’t go bad on the shelf. Verily, this bottle may be the last of its kind, as it’s no longer available from any of the usual sources; it appears I bought it back in 2000.

The blocks are in good shape, probably because they don’t often see the light. FWIW, I have experimentally determined that my body oil doesn’t etch fingerprints into steel.

The block set, which is similar to a current box o’ blocks from Enco, claims “Workshop Grade”, but the ±0.00050 inch = 1.27 μm tolerance shown in the top row of the labels is much worse than even grade B’s sub-micron tolerance. That newer box claims “Economy” accuracy with the same spec, so I suppose somebody kvetched about mis-using the terms.

Ah, well, they’re far better than any measurements I’ve needed in a while and entirely suitable for verifying my other instruments.

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  1. #1 by jim oslislo on 2013-12-27 - 11:21

    Apart from the corrosion issue you discussed, I was reminded that years ago I was taught to use the oil on the end of my nose to wring gage blocks together.

    However, I always suspected that he was the same guy who used to tell the new guys in the navy to go get him fifty feet of shore line :)

    • #2 by Ed on 2013-12-27 - 14:09

      And sent you off to fetch a metric crescent wrench from the tool room.

      From what I read, there’s actually special gauge block oil used for wringing, not that I’ve ever seen (or needed) such a thing…

      • #3 by Red County Pete on 2013-12-27 - 16:16

        Not sure I’d use my nose oil on gage blocks, but I recall my uncle recommending and using nose oil on joints on fishing poles. You can’t lose the source, I suppose…