External Variable Gages

TRI-ROLL External Thread Gage

This gage is ideally suited to thread measuring applications where the gage is to be dedicated to only one thread size or is used to measure a narrow range of sizes. This gage comes in a number of different frame sizes providing a total measurement range of #0-80 (M1.6) through 3⅜” (M85). Each frame size will cover 2 to 4 standard thread diameters in both inch and metric sizes. For example, the #4 frame size covers #10, #12, l/4″ and 5/16″ sizes. This design is best suited to manufacturing applications.
The TRI-ROLL Gage is a three roll, 120 degree contact position design. The following gaging roll types are available:
Thread Characteristic Roll Type ANSI/ASME #
Functional Diameter (UNR) 3 4.3
Functional Diameter (UNJ) 3″J” 4.3 Modified
Pitch Diameter (cone & vee) 4 4.5
Minor Diameter Minor 5.2
Lead & Flank Angle Differential 4.8
Runout (P.D. to major) Runout 4.7
A different set of gaging rolls is required for each thread size to be measured.
TRI-ROLL Gages are set with Gage Class “W” single end, full form, threaded setting plugs. Users having ring gage setting plugs can use them if only the full formed section is used. For the greatest measuring accuracy always set the TRI-ROLL Gage using the calibrated size of the setting plug instead of the nominal size marked on its handle. The result of a long form Gage Repeatability and Reproducibility Study of the TRI-ROLL Gage was 15% with functional diameter gaging rolls and 20% with pitch diameter gaging rolls.
TRI-ROLL Gages with Base, Frame and Electronic Indicator with S.P.C. output:
Inch Metric Single Frame Unit*
#0 thru #1 M1 TRU-100E
#2 thru #3 M2 thru 2.5 TRU-101E
#4 thru #8 M3 thru M4 TRU-102E
#10 thru 5/16 M5 thru M6 TRU-103E
3/8 thru 1/2 M8 thru M12 TRU-104E
9/16 thru 3/4 M14 thru M16 TRU-105E
7/8 thru 1-1/8 M20 thru M24 TRU-106E
1-1/4 thru 1-1/2 M30 thru M38 TRU-107E
1-5/8 thru 1-7/8 M39 thru M47 TRU-108E
2 thru 2-1/4 M48 thru M56 TRU-109E

*NOTE: Double Frame Unit, TRU-2XX, Triple Frame Unit, TRU-3XX


X-180 Segment External Thread Gage

The X-180 Gage is of the two-segment, 180 degree contact design. The single frame size covers #2 (M2) through 3/4″ (M 18). This design can be used to measure functional diameter in all specifications and 180 degree circularity in ANSI/ASME System 23 and SAE AS8879 “Safety Critical” inspection. A different set of gaging segments is required to measure each thread size. The X-180 Gage can be changed from one size to another in less than one minute. The use of the three roll or two segment gage design to measure functional diameter is optional in ANSI/ASME, SAE AS8879. The result of a long form Gage Repeatability and Reproducibility Study for the X-180 Gage was 11 % for measuring functional diameter.

X-120 Adjustable Tri-Roll Thread Gage

The X-120 Gage is the same basic design as the TRI-ROLL Gage, having three rolls which contact the thread at 120 degrees apart. The differences are that the X-120 gage is much more widely adjustable and fewer gaging rolls are required because only one set of rolls is needed for each TPI (threads per inch). There are two gage frame sizes; small, #4 (M3) through 1″ (M24) and large, 1-1/8″ (M30) through 2″ (M50). The thread size can be changed in less than three minutes by simply loosening four screws, adjusting the gaging roll axis pin position with a screw diameter template, retightening the four screws, attaching the gaging rolls, and setting the gage with the threaded setting master.
The X-120 Gage is best suited for use in incoming and final inspection. The following gaging rolls are available:
Thread Characteristic ANSI/ASME #
Functional Diameter 4.3
Pitch Diameter (cone & vee) 4.5
“VARIMINOR” (minor diameters 32 TPI & less) 5.2 Variable
The “X-120” Gage is set with a Class “W”, single end, threaded plug gage. The result of a long form Gage Repeatability and Reproducibility Study for the X-120 Gage was 17% with functional diameter gaging rolls and 25% with pitch diameter gaging rolls.