WESTport ITC Comparators (Internal)

INTERNAL THREAD COMPARATOR

ITC Comparators (Internal)

The ITC measures internal threads (threaded holes) using gaging segments, set with a master setting ring. Build your system: ITC frame (100/200/300), ITC dial indicator, base, gaging segments for your thread, and a master ring.

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ISO/IEC 17025Accredited Calibration
ISO 9001Certified Quality Management
ANSI/NCSL Z540-1Accredited Calibration Lab
Made in USASince 1989

What goes into an ITC system

  • 1. ITC Frame

    Internal-thread comparator body — frames 100 / 200 / 300 by capacity.

    One-time

    Shop ITC frames 

  • 2. Gaging Segments

    The measuring elements (Type 3 / Type 4), specific to your thread size and pitch.

    Per thread size

    Shop Gaging Segments 

  • 3. ITC Dial Indicator

    Reads pitch-diameter variation. ITC uses its own indicator.

    One-time

    Shop ITC indicators 

  • 4. Base & mounts

    ITC base plus the shared dual-frame base and mounting bar.

    One-time

    Bases & mounts 

  • 5. Master Setting Ring

    Internal threads are zeroed with a master setting ring. One per thread size.

    Per thread size

    Shop Setting Rings 
1 5

Choosing your gaging segments

TypeWhat it measuresWhen to choose it
Type 3 — Full ProfileFunctional (assembly) diameter.Pitches coarser than 48 TPI.
Type 4 — Cone & VeePitch diameter, limited flank contact.Pitch-diameter control across all pitches.

ITC frames

FrameCapacity
ITC 100Smallest internal capacity
ITC 200Mid range
ITC 300Largest (up to 8")

ITC measures internal threads (threaded holes), set with a master setting ring. See each frame's product page for exact capacity. The shared dual-frame base and mounting bar from the Tri-Roll line also fit the ITC.

ITC buying questions

When do I use an ITC?

Use the ITC to measure internal threads (threaded holes). For external threads (bolts, studs), use Tri-Roll or STC.

Plug or ring setting master?

ITC is internal, so it's zeroed with a master setting ring (not a plug). One ring per thread size.

Does the ITC share any accessories?

The dual-frame base and multiple mounting bar are shared with the Tri-Roll/STC lines. The ITC uses its own frame, dial indicator, base, and gaging segments.

Adding a new thread size?

Order gaging segments for the new size and pitch, plus a matching master setting ring. Your frame, base, and indicator are reused.

Calibration certificates & lead times?

A Long Form Certificate is available on most items, and we offer ISO 17025–accredited calibration. For lead times on made-to-order segments or rings, call 1-888-400-4243.

Watch: How to Use an ITC Comparator