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23Jun/16Off

New Thread Check Catalog

Thread Check Inc., is proud to announce the release of our 2016 Precision Gage Solutions catalog with over 180 pages of precision gages, measuring instruments and technical information. Our new catalog is available for download or in an electronic book format for easy use. The new catalog has links to www.threadcheck.com where our customers can shop on line, request quotes and view hundreds of technical articles. Use the table of contents to quickly turn to the product selection of your choice. Use electronic book marks for the pages you visit frequently. The new electronic catalog works across all platforms including tables and smart phones.

http://user-CfZTcuf.cld.bz/Thread-Check-Inc-Catalog-2016

Thread Check Catalog 2016 Cover

 

 

21May/14Off

Thread Measuring Wire Calibration

Reference ASME B89.1.17-2001

Attributes to be inspected

  • Diameter – Use high magnification comparator or measuring instrument with adjustable measuring force.  .0000020” resolution or better is required. Use a cylindrical anvil.

 

  • Roundness – Use Vee anvil with 60 degree included anvil. Cylindrical masters and a normalizing plate are required.

 

Suggestions for improved accuracy

Calibrate only in the central middle half of the thread measuring wire.

Thread measuring wires are calibrated on a functional basis so as to compensate for deformation when the wires are being used.

  • Wire diameter is measured with the wire placed over a cylindrical anvil of a known size by a flat round contact point.
  • The effects of errors in roundness are determined by noting the changes in diameter measurement utilizing a vee anvil and taking measurements around and along the wire.

Refer to ASME B89.1.17-2001 for measuring force and contact point configurations.

Wires must be unrestrained during measurement. They should be held in place by the specified measuring contact force only.

The set of 3 wires in a set must be calibrated at the same time to ensure the commonality of size standard is met. Each wire in a set must have the same diameter within .000010”.

Handle all thread measuring wires with care. Wires should be handled with soft tip tweezers

Allow adequate time for thread measuring wires to normalize. Use a normalizing plate adjacent to the measuring equipment.

Measurement Uncertainty

Attribute Normal Laboratory Conditions Optimum Laboratory Conditions
Wire Diameter 0.000025”/ 0.00064mm 0.000015”/ 0.00038mm
Wire Straightness/Roundness 0.000015”/0.000383mm 0.000005”/0.000130mm

 

 

Thread Check Inc.               www.threadcheck.com                info@threadcheck.com

2May/13Off

Gage Certification

Thread Check Inc offers 3 different levels of certification for all gages

1.       Certificate of Compliance (  C of C )

Is a general statement that the gages have been manufactured and are in conformance to the applicable gage specification. The Certificate of Compliance states that the gages have been manufactured and inspected by highly trained personnel and found to comply with the dimensions and tolerances specified. The Certificate of Compliance states that the primary reference standards for the gage calibration are traceable to System International (S.I.) units through the N.I.S. T - National Institute of Standards and Technology. The N.I.S.T. number referenced on this cert is being phased out by the requirements of A2LA. The Certificate of Compliance also states that the gages are inspected in compliance with MIL-STD 45662A, ISO 10012-1, and ANSI/NCSL Z540-1.

The Certificate of Conformance supplied by Thread Check Inc. conforms to the standard scope adopted by the American Measuring Tool Manufacturers Association – AMTMA. It is neither a contract nor a contractual representation.  The Certificate of Conformance states that the company’s responsibilities shall in no event nor for any cause what so ever, exceed the purchase price of the pertinent gage(s).

 

  • NO DIMENSIONAL SIZES OR TOLERANCES ARE LISTED ON THIS DOCUMENT
  • NO COMPANY INFORMATION OR GAGE PRESCRIBED SIZE IS LISTED ON THIS DOCUMENT
  • THREAD CHECK INC. PROVIDES THE CERTIFICATE OF COMPLIANCE FREE OF CHARGE.

 

2.       MANUFACTURER’S LONG FORM CALIBRATION (LFC)

Thread Check Inc. offers a manufacturing Long Form Calibration which provides all the critical gage dimensions and tolerances for the applicable standard. The Manufacturer’s Long Form Calibration demonstrates that the gages have been manufactured and inspected by highly trained personnel and found to comply with the dimensions and tolerances specified in the applicable standard. Long Form Calibration reports for thread gages list Pitch diameters, major diameters, minor diameters, lead, and angles. Long Form Calibration for Plain gages typically list measurements in 3 places. Thread Check does not provide calibration stickers on new gages.

Thread Check Inc. does not issue calibration frequencies on new gages.

Thread Check Inc. does not issue IDs or serial numbers unless specified by the customer.

Thread Check Inc. can supply a serial number at no additional charge if requested by the customer.

 

  • THERE IS AN ADDITIONAL COST FOR THIS RECORD.
  • THERE IS AN ADDITIONAL LEAD TIME INCURRED FOR PURCHASING THIS RECORD.
  • LONG FORM CALIBRATION MUST BE ORDERED WITH THE GAGES OR PRIOR TO THE GAGES BEING SHIPPED.

 

 

3.       ISO 17025 ACCREDITED CALIBRATION (ISO 17025 LFC)

Thread Check Inc. sends the gages to a third party calibration lab that is ISO 17025 accredited. The lab is ACLASS accredited. All critical dimensions are listed on the calibration cert. The laboratory is accredited in accordance with the recognized International Standard ISO/IEC 17025:2005. This accreditation demonstrates technical competence for a defined scope and the operation of a laboratory quality management system (refer to joint ISO-ILAC-IAF Communiqué dated January 2009).

 

  • THERE IS AN ADDITIONAL COST FOR THIS RECORD.
  • THERE IS AN ADDITIONAL LEAD TIME INCURRED FOR PURCHASING THIS RECORD.
  • LONG FORM CALIBRATION MUST BE ORDERED WITH THE GAGES OR PRIOR TO THE GAGES BEING SHIPPED.
13Nov/12Off

Measurement Uncertainties of Adjustable Style Thread Ring Gages

The measurement uncertainty for thread ring gages is calculated from two factors:

The measurement uncertainty of our set plugs which is around 0.000070 depending on size

  1. ANSI/ASME B1.2-1983 Section A3 (p. 164) Section A3.1.2- the measured pitch diameter on rings fitted to a setting plug may be 0.0001 to 0.0002 in. larger than the measured pitch diameter on the plug because the pitch diameter equivalents from permissible pitch, lead, and flank angle tolerance on matched plug and ring cause some unavoidable discrepancy.  So in other words- the standard error between the plug and the ring as stated in the standard.  We err towards 0.0002 as the worst case scenario.

Since there are no established torque values for the degree of drag, the end result is up to technician and ultimately does not constitute a measureable result, like a thread plug or a gage block would.

Please note that ISO/IEC 17025:2005 Section 5.4.6.2 Note 2 “ In those cases where a well-recognized test method specifies limits to the values of the major sources of uncertainty of measurement and specifies the form of presentation of calculated results, the laboratory is considered to have satisfied this clause by following the test method and reporting instructions”.  Calibration of thread rings using set plugs is most assuredly a “well-recognized” test method.

Basically, you have to take into consideration the uncertainty of the set plug and add 200µinches per the standard.

 

Filed under: Calibration No Comments
6Jun/12Off

Gage Makers’ Tolerances

Gage Makers tolerances have been established by the American Gage Design Commitee and are referenced for building and calibrating all solid ring gages, plug gages, and fixed snap gages. Gage Maker tolerances are refered to as classes. For example Class ZZ tolerance is an open tolerance or economical tolerance. There are 6 classes of tolerance - class XXX, XX, X, Y, Z, and ZZ.

See the link below for Gage Maker tolerances in inch and metric

https://www.threadcheck.com/technical-documents/fixed-limit-gage-fact-sheet-pg28.pdf

 

 

6Mar/12Off

Measuring Plain External Diameters – American vs European

A case related to pin gages being rejected by our European Customer

The ASME B89.1.5-1998 is the correct document to review. Reference para. 6.1, pg. 5 & 6 as well as Table 4 on pg. 7. The values were computed using the equation in Puttock and Thwaite’s CSIRO Technical Paper #25. This statement is also on page 6. The question that should be asked is, what is their measurement uncertainty? Remember that the Europeans add measurement uncertainty into their measurements. We do not do that in the US. Depending on the uncertainty budget, they may not have the accuracy to measure a .000020” gage. Our measurement uncertainty is .000012” based on our latest accredited calculations . This is not good enough to accurately measure a Class XX pin. Our customers accept our measurements as long as our uncertainty is stated on the calibration certificates. According to ANSI/NCSL Z540 & ISO 17025 the total uncertainty of the measurement should not exceed 4:1. That would require a total measurement uncertainty of .000005”. The only lab that I know of that can measure this accurately w/in the 4:1 Rule, and prove it, is NIST.

See the link to the NIST web site that has a calculator to assist in the measuring force calculation.

http://emtoolbox.nist.gov/Elastic/Case10.asp

Note: The measuring force changes with the diameter of the part being inspected.

16Jan/12Off

New Measurement Uncertainty Requirements

Effective January 1st, 2012, all ISO/IEC 17025:2005 calibration laboratories are required to begin reporting measurement uncertainties for each measurement result.  Fox Valley Metrology prides itself on being one of, if not the only lab to offer this via automated software.  This automation allows us to provide this service at no additional cost.

For calibration laboratories, ISO/IEC 17025:2005 (clause 5.10.4.2) requires that “if a statement of compliance with a specification is made, this shall identify which clauses of the specification are met or not met”.

When compliance with a specification is made it should be clear to the customer which coverage probability for the expanded uncertainty has been used.  Unless otherwise noted, the coverage probability will be 95%.

 

An explanation of In Tolerance, Out of Tolerance, and Within Uncertainty:

(Case 1) In Tolerance: If the specification limit is not breached by the measurement result plus the expanded uncertainty with a 95% coverage probability, then compliance with the specification can be stated. This can be reported as “In Tolerance”.

(Case 4) Out of Tolerance: If the specification limit is exceeded by the measurement result minus the expanded uncertainty with a 95% coverage probability, then noncompliance with the specification can be stated. This can be reported as “Out of Tolerance”.

(Case 2 & 3) Within Uncertainty:  If the measurement result plus/minus the expanded uncertainty with a 95 % coverage probability overlaps the limit, it is not possible to state compliance or non-compliance. The measurement result and the expanded uncertainty with a 95 % coverage probability should then be reported together with a statement indicating that neither compliance nor non-compliance was demonstrated. A suitable statement to cover these situations would be “Within Uncertainty”.

 

Filed under: Calibration No Comments
6Oct/10Off

White Paper on Resolving Measurement Disputes

Disputes over measurements can be costly for both parties to resolve and may hinder ongoing relations between suppliers and users of gages and instruments. Often it is simpler for both parties to agree to accept an average value of their readings as the final ‘size’ or the point at which their readings plus measurement uncertainties overlap.

The obvious way to avoid such problems is to agree beforehand on a method that will be used to resolve them if they arise. Often, the degree of separation between the readings dictates the best approach to take. Where the uncertainty of each party is significantly different, the party with the lowest uncertainty in the calibration would be considered more reliable.

The AMTMA offers the following methods as options you can choose from. If the Referee Method fails to bring a resolution, then the Universal Standard Method should be used due to the fact it is technically based and internationally accepted by metrologists in all disciplines.

The Referee Method

The two parties agree on a third party to provide a referee measurement that it is agreed will be considered as the actual value. An alternative on this is where the reading by either party that is closest to that provided by the referee is considered the accepted dispute.

Unless otherwise agreed to, the costs of using laboratories in this method are paid by the losing party.

The Unviersal Standard Method

National and international standards agencies have produced methods of resolving measurement disputes that focus on the uncertainty budgets of those that have produced measurements. The advantage of this method is that its technical base tends to remove personalities from the equation and may indicate that neither party to a dispute has the capability required to resolve it.

Using this method, the onus of proving a measurement falls on the party who has questioned the results of calibration. If requested, this party must provide a copy of their uncertainty budget for the measurement to the other party review. Budgets from both parties should be compared. Such a review should focus on seeking agreement between both parties respecting each element included in the budget since it will rarely, if ever, be all right or all wrong. The mathematics should take care of the rest. There may be cases where one or more elements have not been included in the budget included in the budget and when they are, the outcome changes significantly.

In the event one or more assumptions in the budget cannot be resolved, a third party can be asked to provide an opinion on them.

Filed under: Calibration No Comments
30Sep/10Off

CHANGE IN CALIBRATION CERTIFICATE FORMAT

Many customers will soon see a change in how the gaging and metrology industry presents the  N.I.S.T. number on calibration certificates. NIST is the acronym for National Institute of Standards and Technology.

NIST, A2LA, and many auditors are REQUIRING that we no longer list the NIST test report number on calibration certificates. The NIST number would typically change depending on the type of master used for calibration as well as each time the calibration masters were calibrated at NIST.

Thread Check Inc. is substituting the NIST number with the statement “ ….traceable to SI units through NIST”. This change has already taken place with many of our certificates of compliance and accuracy forms. SI is defined as System International

Many customers will be asking about this missing NIST number on their certificates. We are referring them to A2LA document P102-A2LA policy on measurement Traceability available at www.a2la.org  and the NIST policy on traceability located at www.NIST.gov

Filed under: Calibration No Comments
15Sep/10Off

Selecting Gage Blocks

Select gage blocks in accordance with the combination range required. If a large length is required, add a long block set.

Select gage blocks in accordance with the minimum length step required. Add wear block sets if necessary.

If a set containg a large number of gage blocks is selected, the number of combination gage blocks required for a length is reduced and the number of combinations is increased. The accuracy will be retained and damage will be reduced.

The specific gage block set for micrometer inspection and caliper inspection is available.

If using only one length repeatedly, it is a good idea to purchase discrete gage blocks.

The 2mm-based gage blocks, which take the base of the minimum length set as 2mm, are easy to handle and will not warp, as compared to the 1mm-based gage blocks.

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