Tri-Roll Comparators
Variable Thread Gages
SYSTEM 21
System 21 provides for interchangeable assembly with respect to functional size only. Functional size must be measured at the maximum material limit within the length of standard gaging elements. The characteristic known as NO GO functional diameter must also be verified. This can be accomplished by using fixed limit gaging or variable gaging with functional elements.
SYSTEM 21A (FOR METRIC THREADS IN ACCORDANCE WITH ANSI B1.18M)
System 21A provides for interchangeable assembly with functional size verified at the maximum material limit using standard length gaging elements. This can be accomplished using fixed limit gaging or variable gaging with functional elements. System 21A also states that the minimum material limit (minimum pitch diameter) must be verified by inspecting two thread flank locations over the length of the thread. This can be accomplished by using variable gaging or thread roll snap gages with pitch diameter elements.
SYSTEM 22
System 22 provides for the interchangeable assembly with functional size verified at the maximum material limit using standard length gaging elements. This can be accomplished using fixed limit gaging or variable gaging with functional diameter elements. System 22 also states that the minimum material limit (minimum pitch diameter) must be verified over the full length of the thread. This can be accomplished using variable gaging with pitch diameter elements.
SYSTEM 23
System 23 provides for interchangeable assembly with functional size verified at the maximum material limit using standard length gaging elements and minimum material limit (minimum pitch diameter) must be verified over the full length of the thread. The gaging requirements for SYSTEM 22 would also apply here but in SYSTEM 23 other thread characteristics such as lead, flank angles, taper and roundness must have to be independently verified. Only thread characteristics, which are specified, will have to be inspected for SYSTEM 23 compliance.
STC & ITC Comparators
Precision
Ball slide construction and constant gaging pressure assure precise reading through linear travel of the ball slide.
Definitive
Helical path seating and 60% peripheral contact provide functional size position within the pitch diameter tolerance assigned.
Gaging Range
Single frame covers a size range of #10 through 3/4".
Versatile
Segments are easily changed with positive mounting pin alignment.
Economical
Reduced gaging time compared to Go/NoGo gages .
ITC Comparator
Precision
Rigid construction and constant gaging pressure assure precise readings.
Definitive
The ITC gage reads the actual size of the pitch diameter showing its position in relation to the pitch diameter tolerance assigned.
Gaging Range
Single frame covers a size range of #10 through 2 1/2" , Larger frames are available up to 8"
Versatile
The positive alignment feature of the frame allows segments to be easily changed with positive mounting pin alignment.
Economical
Reduced gaging time compared to Go/NoGo gages .
Full Profile-Functional Diameter Size
Full ribbed rolls for functional sizes coarser than 48 T.P.I (For 48 T.P.I and finer the ribs locate on alternate threads)
Cone & Vee Single Element Pitch Diameter
Two ribs ("vee type") on lower rolls (1 and 3) One rib ("cone type") on upper roll (2) Flank contact limited
"Best Wire" Size Radius Single Element Pitch Diameter
Single ribs only with "Best Wire" size radius for any given pitch (T.P.I)
Plain Rolls Thread Major Diameter and Plain Cylindrical Parts.
Straight cylindrical rolls for checking diameter and out of roundness.
(55° included angle)
Two full profile "V" rolls (1 and 3) and one full profile cone roll (2)
Lead/Flank Angle
Two full profile "vee" rolls (1 and 3) with outside flanks relieved. and one full profile cone roll (2)
