Questions tagged [tolerance]
56 questions
17
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3 answers
How does measurement uncertainty combine with tolerances?
Given a tolerance within which your workpiece should be manufactured, say some length should be $10\pm1$mm. If you determine that your uncertainty in measuring this length is $0.2$mm (at 95%). How should a measurement of $9.1$mm be treated?
Clearly…
nivag
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13
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Measuring longer distances with high accuracy
I am involved right now in the fabrication of steel structures on the order of 5-50 feet long. Presently, we measure these structures with garden variety commercial tape measures. Most of the time, we work to a tolerance of about +/-1/16" and don't…
Ethan48
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13
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Distance sensors with accuracy of 1 mm?
I am making a device for measurements. I would like to measure the distance within accuracy of 1 mm. Range could be 2 cm to 15 cm . I looked at Proximity Sensors but the readings displayed by these sensors are not steady.
I wish to measure the…
JustCurious
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How to find press fit/ slip fit for non standard size parts?
I am looking for calculator or chart for slip fit and press fit for non standard size parts.
For example, I have oversized dowel pin 10mm +0.03/+0.01 diameter. I need to create a slip fit hole for that oversize dowel pin. What the size and the…
Marco
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6
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1 answer
What does a divide symbol on a drawing mean?
What does this dimension (see image), and particularly the divide symbol in it, mean please? I'm not a mechanical engineer and couldn't find the answer by searching for terms with the word "divide" in them.
If it makes any difference, I guess the…
Cog77
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5
votes
1 answer
Specification of hole design tolerance
Suppose the fit for a rod and a hole in a gear is supposed to be free running and the fit is 3mm H9/d9. For the specification of the hole for the manufacturing of the gear, is "3mm H9" already adequate since d9 only refers to the shaft tolerance…
WKleinberg
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5
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2 answers
Typical flatness of Portland cement
Does anyone have a feel for the flatness of Portland Cement when poured in a standard/typical way? Say, for example, that I wanted to pour a cement "cube" (20"x 18"x 19.25") in a mold. How flat would the top surface be without any special…
willpower2727
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4
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How to specify and tolerance a "sharp" point?
I need to have an electrical probe machined; but I am unsure how to specify my requirements. I am an electrical engineer with only moderate mechanical knowledge.
The probe will be machined from 0.125" diameter stainless steel round stock. The last…
PaulB
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3
votes
1 answer
Placing machine visions targets with high accuracy
My company is working on a machine vision application. One of our requirements is that the camera peer through a frame (like a picture frame - see here ), where the top and bottom border are etched with machine vision targets. The frame is…
user3614305
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3
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1 answer
Why/when do we use a transition fit?
I'm self-learning a bit about preferred fits and tolerances and was wondering why transition fits were even a thing.
Clearance fits I understand, applications where you don't want parts to touch and "clear" each other.
Interference fits are for…
TwoWaySpeedOfLight
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3
votes
2 answers
What are the longitudal tolerances of thread on metric nuts and bolts?
It's not exactly my area of expertize and I've spent a couple hours ears deep in norms, and I'm not really sure if what I found is correct (the figure I found was to the order of 1$\mu$m).
When using standard (off-the-shelf, not specialized)…
SF.
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2
votes
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What is the difference between incremental and cumulative error?
In a description for ballscrews on a CNC, I saw two types of error listed:
Incremental error: < 0.0006"/ft
Cumulative error: < 0.0008" at 35"
What are these types of error measuring? What is the difference between them?
guest123
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2
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ISO 1101 & 14405: Required number of measurements for evaluation of dimensions and GTOLS
To my knowledge, standards ISO 1101 (for dimensions) and ISO 14405 (for GTOLs) make no statements whatsoever as to the required number of measurements for evaluation of quantities specified therein.
To give one example, if a diameter is to be…
chicken_game
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2
votes
2 answers
Assist for vertically telescoping support?
Two questions.
Has anyone had experience in retrofitting consumer (locally-available) square aluminum tube as telescoping structural support? Ergo; with 0.125" wall thickness square tube at an outside dimension (OD) of 1.5", would minor superficial…
Katalpa
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2
votes
2 answers
Coplanarity Profile Callout Confusion
From Krulikowski (1997), the callout for several coplanar surfaces using the Profile symbol is done by using two surfaces to establish datum plane A-B and then tolerancing the remaining coplanar surfaces in reference to A-B.
Can other non-coplanar…
Bawb
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