Low cost slim glass scale

Winegrower said:
Well, then I have more diagnostic work to do. Thanks for the info, Yurily!

I am not sure if my expectations are reasonable...that gauge blocks measured with a 0.0001 dial indicator, ought to give the right answer within maybe a few microns. You think?
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Before you go too deep into the rabbit hole (sorry, I think I'm actually digging said hole here...):
Your tenth's indicator (if you have a really good one) has +/-0.0001" maximum error when new (that's what Mitutoyo states in their specs, for example), so even if you do everything perfect, you can be off by +/- 2.5 um. This is not even taking into account temperature, etc.
I don't know how you tested/calibrated your scales, but with a 0.0001" indicator and a gauge block, the approach you can take is:
"When my DRO shows X, does the indicator show X as well". You can't go the other way around (i.e. "my indicator shows X, does the DRO show X".

To properly measure the error in the scales you need something that has more resolution and is inherently more accurate. One of these (photo) can measure down to double digit nanometers (well, when it's not sitting on my beat up kitchen table), and it takes a LOT of effort to get repeatable measurement of 1um scales.

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I.e. what I'm saying is "don't stress about it". Given that you bought your scale for a decent price that doesn't look like it was a "fell of the truck" unit. As long as you get reasonable readings from your thents indicator, you'll not be lacking in accuracy.

Regards
Yuriy
 
Ok, great. Thanks for the advice. I'm feeling much better now.
 
ycroosh said:
Yeah, I got these crossed in my mind, sorry. This is a long thread ... :)
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No problem Yuriy, carry on i just wanted to clarify the thread, it is all important info.
 
I installed the 1um KA300 on the Z axis of the Takisawa. It was not particularly easier or harder than any other scale I've installed (probably 8 systems)...none of them make it very simple, everything I've installed so far has had to use a mill and bandsaw to fabricate mounting brackets, etc.

And after trying to establish the 1um accuracy, I believe Yurily's advice is pure wisdom..."don't worry about it". I did everything I could think of with 0.0001 indicators and gage blocks, and never felt comfortable. Eventually I mounted my old Starret vernier height gauge on the chuck, and used that for distances of around 15". I threw out all the fussy calibration I did on shorter distances, set the gauge to 2" and zeroed the DRO at that point, moved the gauge out to 17" (using a magnifier to set the vernier...it's surprising how accurate it can be) and got 15.0001. A fluke, but I think if you're good at long distances, it's probably OK for shorter. I'm through messing with it anyway. If parts keep coming out wrong, maybe I'll look again, or just do more woodworking. :)
 
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