TECHNICAL MANUAL CALIBRATION PROCEDURE FOR THREADED PLUG GAGES This publication replaces T.O. 33K6-4-203-1 dated 30 January 2013. Distribution Statement C - Distribution authorized to U. S. Government agencies and their contractors for official use or for administrative or operational purposes only, 30 December 2001. Requests for this document shall be referred to AFMETCAL, 813 Irving-Wick Dr W, Heath, OH 43056-1199. Destruction Notice - For unclassified, limited documents, destroy by any method that will prevent disclosure of the contents or reconstruction of the document. Published under Authority of the Secretary of the Air Force 30 MAY 2013
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THREADED PLUG GAGES 1 CALIBRATION DESCRIPTION: Table 1. Test Instrument (TI) Performance Test Characteristics Specifications Method Pitch Diameter Range: N/A Verified using Thread Wires and Standard Accuracy: Refer to appropriate Measuring Machine Thread Standard identified in Appendix B Major Diameter Range: N/A Verified using Standard Measuring Machine Accuracy: Refer to appropriate Thread Standard identified in Appendix B 2 EQUIPMENT REQUIREMENTS: Minimum Use Calibration Sub- Noun Specifications Equipment Item 2.1 LABMASTER Range: 0 to 13 in Pratt & Whitney UNIVERSAL U306270 Accuracy: 2 + (0.5 x L) in, Where L is TI nominal diameter in inches * 1 2.1.1 SOFTWARE Range: N/A T.O. 33K6-4-9020-10 PACKAGE Accuracy: N/A 2.1.2 ADJUSTABLE Range: 0 to 40 oz Pratt & Whitney TAILSTOCK U306469 Accuracy: 10% of setting 2.1.3 FLAT ANVILS Range: N/A Pratt & Whitney U306538 Accuracy: Flatness and Parallelism, 12 in TIR See footnotes at end of Equipment Requirements. 1
Minimum Use Calibration Sub- Noun Specifications Equipment Item 2.2 UNIVERSAL Range: 0 to 8 in Mahr MEASURING 828WIN/39 INCH MACHINE Accuracy: 15 in * 2 Range: 8 to 40 in Accuracy: (20 + L) in, Where L is in inches; (0.5 + L/1000) m, Where L is in mm * 2 2.2.1 SOFTWARE Range: N/A T.O. 33K6-4-9022-10 PACKAGE Accuracy: N/A 2.3 DIGITAL FORCE Range: Up to 8 oz Chatillon GAGE * 3 DFE Series Accuracy: 0.3 oz Range: Above 8 to and including 40 oz Accuracy: 3.5 oz 2.4 GAGE BLOCK SET Range: 0.2 to 1 in Mitutoyo (USED WITH 5 LABMASTER Accuracy: Not to exceed UNIVERSAL) 2 in from stated value * 1 Range: 2 to 4 in Accuracy: (1.2 + 0.7L) in from stated deviation, Where L = length in inches * 1 2.5 GAGE BLOCK SET Range: 0.5 to 4 in DoAll Pratt & Whitney 36 81 Accuracy: 6 in from stated value * 2 2.6 GAGE BLOCK SET Range: 5 to 20 in L.S. Starrett 8 Accuracy: 2 in/in from stated value * 1, * 2 2.7 THREAD WIRES Range: 0 to 80 PD Van Keuren Van Keuren (ONE SET OF THREE GGG-W-366B/T 34HS FOR EACH PITCH) Accuracy: 25 in * 1, * 2 2.8 ALCOHOL-ETHYL Range: N/A As Required Accuracy: N/A 2
* 1 The worst case combined TAR of (2.1), (2.4), (2.6) and (2.7) is 2.2:1 for Pitch Diameter. * 2 The worst case combined TAR of (2.2), (2.5), (2.6) and (2.7) is 1.9:1 for Pitch Diameter. * 3 Used to set gaging force if the measuring force on the Tailstock of the Universal Measuring Machine or Labmaster Universal is not calibrated. 3 PRELIMINARY OPERATIONS: 3.1 Review and become familiar with the entire procedure before beginning the Calibration Process. WARNING Unless otherwise designated, and prior to beginning the Calibration Process, ensure that all test equipment voltage and/or current outputs are set to zero (0) or turned off, where applicable. Ensure that all equipment switches are set to the proper position before making connections or applying power. If not strictly observed, could result in injury to, or death of, personnel or long term health hazards. WARNING Alcohol is an eye and skin irritant. Use protective equipment (chemical splash goggles and gloves) where potential of splash and skin contact may occur. Failure to do so may result in injury. If eye contact should occur, flush well with water and seek immediate medical attention. If not strictly observed, could result in injury to, or death of, personnel or long term health hazards. WARNING Alcohol is a flammable liquid and may be ignited by heat, sparks, or flames. Vapors may travel to a source of ignition and flash back. Alcohol burns with an almost invisible flame. If not strictly observed, could result in injury to, or death of, personnel or long term health hazards. 3.2 Thoroughly clean threads with solvent and/or Alcohol to remove all foreign matter and blow dry with clean dry air. 3.3 Visually inspect TI flanks and crest of thread for any nicks or burrs which would prevent proper fit in use. 3.4 The temperature of the calibration area must be 68 1 F and must not vary more than 2 F in the 4 hours prior to and during the Calibration Process. 3.5 Refer to Appendix B for a list of acceptable Thread Standards that can be used to obtain TI Pitch Diameter and Major Diameter specifications. Canceled and/or outdated Thread Standards are acceptable to use because the specifications do not change. 3.6 When using the Labmaster Universal, verify T.O. 33K6-4-9020-10 is the most recent version per the AF TO Catalog or equivalent. 3.7 When using the Labmaster Universal, it is acceptable to refer to T.O. 33K6-4-121-1 and/or equipment manuals for setup and operational information. Verify T.O. 33K6-4-121-1 still meets the requirement. 3
3.8 When using the Universal Measuring Machine, verify that T.O. 33K6-4-9022-10 is the most recent version per the AF TO Catalog or equivalent. 3.9 In all cases, refer to equipment manuals for unanswered questions. 3.10 This is a General Threaded Plug Gage Calibration Procedure for measuring Pitch Diameter and Major Diameter of Class X, Class W and other external threads. 3.11 Connect test equipment to an appropriate power source. Set all POWER switches to ON and allow warm-up as required by the manufacturer. 3.12 Perform only those portions of the Calibration Process, that pertain to the TI being calibrated. 4 CALIBRATION PROCESS: Unless otherwise specified, verify the results of each test and take corrective action whenever the test requirement is not met, before proceeding. 4.1 PITCH AND MAJOR DIAMETER CALIBRATION: (Using Labmaster Universal) 4.1.1 Install the Adjustable Tailstock and a Flat Anvil onto the Labmaster Universal. 4.1.2 Refer to Table 2 and set the appropriate gaging force for the TI being calibrated. If the Adjustable Tailstock is not calibrated, set the gaging force using the Digital Force Gage. Table 2. Thread Gaging TI Type Wires Thread Per Inch Pitch (mm) Force (oz) 60º and Screw 60º >140 N/A 2 Thread Inserts (STI) >80 to 140 N/A 4 >40 to 80 N/A 8 >20 to 40 N/A 16 20 N/A 40 60º (metric) 60º N/A 0.20 to 0.35 4 N/A >0.35 to 0.60 8 N/A >0.60 to 1.25 16 N/A >1.25 40 29º Acme (All) 29º N/A N/A 40 7º/45º Buttress (All) 7º/45º N/A N/A 40 4
4.1.3 Select and clean an individual Gage Block that will be used to set the Labmaster Universal Datum. For TIs 4 inches diameter, the Datum Gage Block shall be within 1 inch of the TI nominal diameter. For TIs >8 inches diameter, the Datum Gage Block shall be within 2 inches of the TI nominal diameter. The Datum must be set using Gage Block Sets (2.4) and/or (2.6). 4.1.4 Select and clean two individual Gage Blocks that will be used to set the Labmaster Universal Scale Factor. The nominal difference between the two Gage Blocks shall be to TI nominal diameter. The Scale Factor must be set using Gage Block Sets (2.4) and/or (2.6). 4.1.5 Refer to Table 2 and select the appropriate Thread Wires for the TI being calibrated. Note the AFPSL Certified Constant as recorded on the Certificate of Calibration for the Thread Wire Set used. 4.1.6 Place selected Gage Blocks, TI and Thread Wires near the Labmaster Universal staging table to stabilize: TIs and Gage Blocks 4 inches diameter shall stabilize for 1 hour; TIs and Gage Blocks >4 inches to 12 inches diameter shall stabilize 1.5 hours; Thread Wires shall stabilize for 30 minutes. 4.1.7 Using selected Gage Blocks, set the Labmaster Universal Datum and Scale Factor. Ensure certified Gage Block deviations are applied. 4.1.8 Refer to Figures 1 and 2 as necessary. Using the selected Thread Wires, measure and record the Measurement Over Thread Wires (MOW) near each end and the center on the TI. THREAD WIRES STANDARD MEASURING MACHINE measuring contact point contact TI PD D MOW STANDARD MEASURING MACHINE contact point Where: PD = Pitch Diameter MOW = Measurement Over Thread Wires D = Major Diameter Figure 1. 5
TOP Figure 2. 4.1.9 Rotate TI 90º and repeat step 4.1.8 for a total of 6 measurements. 4.1.10 Refer to Figure 3 as necessary. Measure and record the Major Diameter near each end and the center on the TI. When measuring TI Major Diameter, it is acceptable to replace the Adjustable Tailstock with two Flat Anvils. If two Flat Anvils are used, the Labmaster Universal Datum and Scale Factor must be re-set. TOP Figure 3. 6
4.1.11 Rotate TI 90º and repeat step 4.1.10 for a total of 6 measurements. Refer to Appendix A for TI Pitch Diameter calculation and tolerances. 4.1.12 Calculate and record the TI Pitch Diameter. 4.1.13 Refer to the applicable Thread Standard listed in Appendix B. All recorded TI Pitch and Major Diameters must meet the required specifications listed in the applicable Thread Standard for the TI being calibrated. 4.1.14 Calibration complete. Remove the TI and the Thread Wires from the Labmaster Universal. Set all POWER switches to OFF, disconnect and secure all equipment. 4.2 PITCH AND MAJOR DIAMETER CALIBRATION: (Using Universal Measuring Machine) 4.2.1 Set the Universal Measuring Machine for external measurements. 4.2.2 Refer to Table 2 and set the appropriate gaging force for the TI being calibrated. If the Adjustable Tailstock is not calibrated, set the gaging force using the Digital Force Gage. 4.2.3 Select and clean an individual Gage Block that will be used to reference the Universal Measuring Machine. For TIs 4 inches diameter, the reference Gage Block shall be within 1 inch of the TI nominal diameter. For TIs >8 inches diameter, the reference Gage Block shall be within 2 inches of the TI nominal diameter. The reference must be set using Gage Block Sets (2.5) and/or (2.6). 4.2.4 Refer to Table 2 and select the appropriate Thread Wires for the TI being calibrated. Note the AFPSL Certified Constant as recorded on the Certificate of Calibration for the Thread Wire Set used. 4.2.5 Place selected Gage Blocks, TI and Thread Wires near the Universal Measuring Machine to stabilize: TIs and Gage Blocks 4 inches diameter shall stabilize for 1 hour; TIs and Gage Blocks >4 inches to 12 inches diameter shall stabilize 1.5 hours; Thread Wires shall stabilize for 30 minutes. 4.2.6 Using selected Gage Blocks, reference the Universal Measuring Machine. Ensure certified Gage Block deviations are applied. 4.2.7 Refer to Figures 1 and 2 as necessary. Using the selected Thread Wires, measure and record the Measurement Over Thread Wires (MOW) near each end and the center on the TI. 4.2.8 Rotate TI 90º and repeat step 4.2.7 for a total of 6 measurements. 4.2.9 Refer to Figure 3 as necessary. Measure and record the Major Diameter near each end and the center on the TI. 4.2.10 Rotate TI 90º and repeat step 4.2.9 for a total of 6 measurements. Refer to Appendix A for TI Pitch Diameter calculation and tolerances. 4.2.11 Calculate and record the TI Pitch Diameter. 4.2.12 Refer to the applicable Thread Standard listed in Appendix B. All recorded TI Pitch and Major Diameters must meet the required specifications listed in the applicable Thread Standard for the TI being calibrated. 4.2.13 Calibration complete. Remove the TI and the Thread Wires from the Universal Measuring Machine. Set all POWER switches to OFF, disconnect and secure all equipment. CALIBRATED PERFORMANCE TABLE Not Required 7/(8 Blank)
APPENDIX A Pitch Diameter Calculation And Pitch/Major Diameter Tolerances Pitch Diameter: Calculate the Pitch Diameter (PD) using the following equation: Calculated Pitch Diameter must meet the required specifications listed in the applicable Thread Standard for the TI being calibrated. PD = MOW - C Where: PD = Pitch Diameter MOW = Measurement Over Thread Wires C = AFPSL Certified Constant Pitch Diameter Tolerance: For Class X (Working Threaded Plug Gages): Pitch Diameter Go Tolerance:... Minus 0, Plus Tolerance (-0, + Tolerance) Pitch Diameter No-Go Tolerance:... Plus 0, Minus Tolerance (+0, - Tolerance) For Class W (Setting Threaded Plug Gages): Major Diameter: Pitch Diameter Go Tolerance:... Plus 0, Minus Tolerance (+0, - Tolerance) Pitch Diameter No-Go Tolerance:... Minus 0, Plus Tolerance (-0, + Tolerance) The measured Major Diameter must meet the required specifications listed in the applicable Thread Standard for the TI being calibrated. Major Diameter Tolerance: Major Diameter Go Tolerance:... Minus 0, Plus Tolerance (-0, + Tolerance) Major Diameter No-Go Tolerance:... Plus 0, Minus Tolerance (+0, - Tolerance) A-1/(A-2 Blank)
APPENDIX B Thread Standards List Thread Standards: The following list of Thread Standards are acceptable for use. Cancelled and outdated Thread Standards can be used to determine TI specifications. Unified: (60º) Acme: (29º) ASME B1.1, Unified Inch (UN and UNR) ASME B1.5, Acme ASME B1.2, Gages and Gaging Unified Inch Screw Thrds ASME B1.8, Acme Stub ASME B1.10M, Unified Miniature FED STD H28-13 ASME B1.15, Unified Inch (UNJ) FED STD H28.12 ACME FED STD H28-6, (Gages and Gaging for Unified) FED STD H28.21 ACME Mil Std-114C, Class X Go Thread Plug FED STD H28.22 ACME Mil Std-115B, Unified Mil Std-116B, Class X Go Thread Ring and Plug Metric: Mil Std-117B, No Go Thread Ring & Related Plugs ASME B1.3M, Metric Mil Std-273B, Class W Go Thread Plug Gage ASME B1.13M, Metric Mil Std-274B, Class W No Go Thread Plug ASME B1.22M, Metric FED STD H28.21, Metric Buttress: (7º/45º) FED STD H28.22, Metric ASME B1.9, Buttress FED STD H28-14 Screw Thread Insert (STI): General Thread Information: Mil-T-21309E ASME B1.7M, Noun, Def A-A-59158 FED STD H28.1 FED STD H28.19 B-1/(B-2 Blank)