VARIABLE THREAD COMPARATORS
Thread Comparators
Variable thread comparators give a live reading of actual thread size — faster than GO/NO-GO gages. WESTport offers all three lines: Tri-Roll and STC for external threads, and ITC for internal threads. Use the guides below to choose the right comparator, frame, and roll/segment type, or call 1-888-400-4243.
Request a QuoteISO/IEC 17025Accredited Calibration
ISO 9001Certified Quality Management
ANSI/NCSL Z540-1Accredited Calibration Lab
Made in USASince 1989
How a thread comparator system works
Every comparator is built from the same five parts. The frame, dial indicator, and base/mounts are one-time purchases; the measuring elements (gaging rolls or segments) and the setting master are specific to each thread size you inspect.
| Part | Tri-Roll | STC | ITC |
|---|---|---|---|
| Frame | #0–12 | STC-101 / 201 | 100 / 200 / 300 |
| Measuring element | Gaging rolls | Gaging segments | Gaging segments |
| Dial indicator | Shared (Tri-Roll & STC) | ITC indicator | |
| Base & mounts | Shared across all three | ||
| Setting master | Plug (external) | Ring (internal) | |
Pick your comparator above to see its complete system and pricing.