Diameter Tolerance for Milled Cylinder - Question

G

grantmaker

#1
I aplogize if this is in the wrong forum but I recently saw a drawing for a small stainless milled cylinder part that had a specification of 1.098 inches, plus .002 inches and - .000 inches. The incoming part is being inspected with a non-digital dial type caliper with an accuracy of +/- .001 inches.

1) What does the -.000 inches mean? and 2) can it be inspected with the caliper they are using?

Thanks,
 
Elsmar Forum Sponsor

normzone

Trusted Information Resource
#2
Can it be? Yes. Somebody is doing it.

Should it be? No. If the device discriminates to .001, then your reliable range that you can safely start or finish arguments in measurements no closer than .002.

Technical arguments might be made to the contrary but the inspection practice as described is not reliable.
 
P

PaulJSmith

#3
1) It means that the acceptable range for that feature is 1.098 to 1.100. It can be .002 larger, but cannot be smaller than the nominal value.

2) see normzone's reply above
 

Michael_M

Trusted Information Resource
#4
I aplogize if this is in the wrong forum but I recently saw a drawing for a small stainless milled cylinder part that had a specification of 1.098 inches, plus .002 inches and - .000 inches. The incoming part is being inspected with a non-digital dial type caliper with an accuracy of +/- .001 inches.

1) What does the -.000 inches mean? and 2) can it be inspected with the caliper they are using?

Thanks,

1) What does the -.000 inches mean?
The specification is calling for 1.098 +.002/-.000. Another way to look at this is 1.099 +/-.001. The -.000 is saying you have .000 as a minus tolerance to your specific dimension as shown. This is a common tolerancing method I have seen when 'fit' (something has to fit--particularly press fit) is important.


2) can it be inspected with the caliper they are using??
As stated above, it can be done but calipers are not a good device to measure this with.
 
G

grantmaker

#5
Thanks all for the quick response. I don't think the spec is meant to be 1.099 + or - .001 as they are adamant they have .002 inches 'to play with' rather than .001 inch.

Would a reasonable recommendation be to use a calibrated micrometer with an accuracy of at least .0001 for a proper TUR? Also, in a rare instance (using a mic with .0001 accuracy), I'm assuming the part would be out of spec if the micrometer showed exactly 1.098.
 

Michael_M

Trusted Information Resource
#6
Thanks all for the quick response. I don't think the spec is meant to be 1.099 + or - .001 as they are adamant they have .002 inches 'to play with' rather than .001 inch.
.
In both cases, 1.099 +/-.001 or 1.098 +.002/-.000, you have a total of .002 tolerance to play with. The part has to measure between 1.098 and 1.100.
 
G

grantmaker

#7
Right! Thanks for the clarification. The two methods of showing the spec are saying the same thing.
 

Ronen E

Problem Solver
Staff member
Moderator
#8
Right! Thanks for the clarification. The two methods of showing the spec are saying the same thing.
That's true only in the old QC school, where all that mattered was "are we within tolerance, or not?". I.e. does the part pass or fail?

In the "new" QA school (which is actually decades old), importance is also placed on the nominal, i.e. the preferred or "ideal" value, and how close to it the part is. A symmetric tolerance means that the preferred value is in the middle, and deviations in both directions are equally "bad" (of course, the bigger the worse), to the point that the tolerance is exceeded and the part fails. In a one-sided tolerance specification, it is actually preferred that the part is as close as possible to the nominal, without going past it. Deviating in the other direction may still be acceptable (within tolerance) but is not preferred.

Cheers,
Ronen.
 
Thread starter Similar threads Forum Replies Date
K Maximum Material Condition on Diameter Tolerance Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4
G Cpk vs. "Bad" Parts - Unreasonable Diameter Tolerance and a 1.67 Cpk Statistical Analysis Tools, Techniques and SPC 22
Marco Bernardi MMC & LMC modifiers and CMM measuring techinques like diameter least squares and circularity or minimum/maximim diameter. Calibration and Metrology Software and Hardware 2
V Thread Plug Gage Pitch GO Diameter out of spec AQL - Acceptable Quality Level 8
S Formula for Calculating NoGo Major Diameter for UN gages Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4
S Minor diameter of threaded ring gage General Measurement Device and Calibration Topics 1
O Thread Diameter as a Datum Inspection, Prints (Drawings), Testing, Sampling and Related Topics 1
O Can a Profile of a Surface have a Diameter Symbol? Inspection, Prints (Drawings), Testing, Sampling and Related Topics 3
M Cp & Cpk about a diameter measured with min.,max. and average values. Capability, Accuracy and Stability - Processes, Machines, etc. 13
M Repeatability issue in Gage R&R study for inner diameter of a bushing Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 16
kedarg6500 How to calculate Thread Pitch Diameter for non standard TPI like 5/8" 17.75 NF3 Manufacturing and Related Processes 3
I 3 legged 5 Why - Hole diameter Oversize caused by Gauging Problem Solving, Root Cause Fault and Failure Analysis 9
M Micrometer Anvil Placement to measure the diameter of Steel Wires Measurement Uncertainty (MU) 6
N Formula that will calculate the NoGo Major Diameter of an M20 x 1.5 6H Thread gage Inspection, Prints (Drawings), Testing, Sampling and Related Topics 3
J Thread Gauge Calibration Failure for Pitch Diameter being too large General Measurement Device and Calibration Topics 3
D Relationship between Diameter and Flow Rate & the Length Statistical Analysis Tools, Techniques and SPC 3
Frank T. How could this Hole Diameter and True Position problem have been Detected & Prevented Nonconformance and Corrective Action 27
M Calculation for Correction Deformation (Pitch Diameter) General Measurement Device and Calibration Topics 3
B Over Size Diameter Counter Sinks - Shop Practice Standard or BAC Specification Manufacturing and Related Processes 3
S Offline Laboratory Scale Gauges for Min Max Diameter of Round Steel Bars General Measurement Device and Calibration Topics 6
somashekar Measurement of Diameter of Thin Wall Plastic Tubes Manufacturing and Related Processes 6
R Maximum allowed eccentricity for any shaft or hole diameter Misc. Quality Assurance and Business Systems Related Topics 7
J Inspection Methods on Internal Diameter of a 10 feet Tube Inspection, Prints (Drawings), Testing, Sampling and Related Topics 10
K Calibrating Plain Tapered Bores at the Small End Diameter General Measurement Device and Calibration Topics 7
P Drift Gauge Design to Check 5.235 +.004/-.000 Diameter Design and Development of Products and Processes 1
M Calibration and Determine Pitch Diameter of Tapered Thread General Measurement Device and Calibration Topics 3
S Instrument to check Internal Bottled Deep Bore Diameter Inspection, Prints (Drawings), Testing, Sampling and Related Topics 7
L Pitch Diameter for a Thread Setting Plug 4.3750-8 ACME-2G, GO/ NO GO General Measurement Device and Calibration Topics 6
D Measuring Minor Diameter of external thread General Measurement Device and Calibration Topics 1
C ID (Inside Diameter) Threads Shrinking due to Heat Treatment and Weld Manufacturing and Related Processes 11
P Inner Diameter Surface Finish Ra Value vs. Surface Finish Graph Output Manufacturing and Related Processes 11
hogheavenfarm Does "Diameter" Automatically Imply "Circle"? Manufacturing and Related Processes 4
E Measuring a .250 diameter hole +/.005 in Thin Laminates Inspection, Prints (Drawings), Testing, Sampling and Related Topics 23
Proud Liberal Using Multiple Plug Gages check a large diameter Inspection, Prints (Drawings), Testing, Sampling and Related Topics 2
B Traceability to the Thimble of ID (inside diameter) Micrometers and Depth Micrometers Calibration Frequency (Interval) 2
C Help me out please - Trig diameter question Inspection, Prints (Drawings), Testing, Sampling and Related Topics 10
D Formula for Determining Finished Good Roll Diameter Manufacturing and Related Processes 7
P Attribute or Variable Measurement? Outer Diameter of a Tube Inspection, Prints (Drawings), Testing, Sampling and Related Topics 6
C Gage R&R for Uni-Micrometers on a rod or bar OD (Outside Diameter) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
M Cp, Cpk, Dpm, or other? Diameter of a Hole - Non-Normal Distribution Capability, Accuracy and Stability - Processes, Machines, etc. 20
C Improving Small Diameter Cable Length Measuring Techniques - Process Improvement Preventive Action and Continuous Improvement 3
D How to Measure a Diameter - Average or Maximum/Minimum? Inspection, Prints (Drawings), Testing, Sampling and Related Topics 25
C Internal Diameter Measurement and Pin Gage Calibration General Measurement Device and Calibration Topics 6
antoine.dias Definition Rv and RvK in Statistical Analysis - Inner diameter between the bearing rollers Definitions, Acronyms, Abbreviations and Interpretations Listed Alphabetically 1
L Internal threads - Maximum / Minor accept/reject diameter inspection Inspection, Prints (Drawings), Testing, Sampling and Related Topics 6
M Combining Data - Measured sizes of hole diameter onto one chart? Statistical Analysis Tools, Techniques and SPC 2
Q Maximum minor thread diameter of UNF internal threads Inspection, Prints (Drawings), Testing, Sampling and Related Topics 7
J Using Gage Pins - Inside diameter - Interference fit General Measurement Device and Calibration Topics 4
J Question on measure used for Gage R&R - Characteristic is a Knurled diameter Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
S Doubt on Thread Measurement - Measuring Fluted (Odd) Taps for its pitch diameter Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4

Similar threads

Top Bottom