Air Gaging Systems · Air Plugs · Air Rings
Air Gaging
The fastest, most repeatable way to measure IDs, ODs, and geometric form on the shop floor — non-contact, self-cleaning, accurate to millionths of an inch.
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Air gaging is the fastest, most repeatable way to measure inside diameters, outside diameters, and geometric form on the shop floor. Instead of touching the part, an air gage reads a dimension from the back pressure or flow of air escaping between precision jets and the workpiece — so it is non-contact, self-cleaning, and accurate to millionths of an inch, with typical magnification from 1,000:1 to 10,000:1. Because it measures from the mean surface rather than from roughness peaks, air gaging gives a truer reading than contact methods, at production speed. WESTport has manufactured, sourced, and calibrated air gaging systems since 1989 in a climate-controlled, ISO/IEC 17025 accredited facility.
The WESTport air gaging line
This collection covers the complete air gaging system — from a single replacement plug to a fully configured multi-channel setup. Every item is compatible with Mahr/Federal, Edmunds, Sheffield, GAR, Universal Gage, and Western Gage tooling, so you can expand or upgrade without rebuilding your gaging system.
- Air Plugs (internal diameter). Opposed air jets measure bore ID with sub-micron repeatability from 0.120″ to 6.010″. Standard through-hole, blind-hole, counterbore, deep-hole / long-reach, leaf-contact (for cast, knurled, or interrupted surfaces), and taper styles.
- Air Rings (external diameter). Jets set around the ring bore measure shaft and OD dimensions as the part passes through — faster and more repeatable than snaps for high-volume work. Standard fixed-size, adjustable, and split / flanged configurations.
- Air Snap Gages. A C-frame or fork that brings the jets to the part instead of the part to the gage — ideal for long shafts and large components. Fixed, adjustable, and blade-type groove-width models for OD, wall thickness, and groove checks.
- Air Spindles. Plug-style tooling built for long bores and automated, in-process gaging cells. Standard and long / extended-reach lengths.
- Digital Comparators & Amplifiers. Single- and multi-channel (2–8 channel) readouts with USB, RS232, RS485, and Ethernet output for direct SPC integration. Our SR1-TR is a drop-in replacement for Federal D1250–D8000, GAR, TRICO, and OILMASTER columns — swap the readout, keep the tooling.
- Setting Masters. Air gaging is a two-point system: a minimum and maximum master define the zero and span of your readout. We manufacture master ring gages, master setting discs, and master plug gages — precision ground and hand-lapped, with NIST-traceable long-form certification.
- Jet Probes, Nozzles & Accessories. Replacement jet probes and nozzle bodies, plus the air regulators, filters, hose and connector assemblies, and manifolds that keep a system delivering accurate readings.
- Oil Well Gaging. The SR1-TR configured for subsurface pump-barrel inspection, with probes and spindles in sizes 1.000″–5.000″ and hose assemblies to 60″.
- Custom Air Gages. Taper, multi-jet, differential, and automated in-process gages engineered to your print. Send a drawing with nominal dimensions and tolerances to start a quote.
What air gaging inspects
Beyond straight ID and OD, air gaging captures the geometric characteristics that are hard to measure any other way:
Air gaging vs. contact gaging
Contact gaging reads from the surface roughness peaks of the part; air gaging reads from the mean surface — the average of peaks and valleys. That difference is why air gaging is preferred wherever surface finish, speed, or repeatability matters.
| Air gaging | Contact gaging | |
|---|---|---|
| Contact | Non-contact | Physical contact |
| Measures from | Mean surface | Roughness peaks |
| Speed | Very fast, ideal for high volume | Slower per part |
| Wear on part & gage | Minimal | Higher |
| Best for | Bores, ODs, roundness, taper, matching | General-purpose & single checks |
Industries served
Automotive
Engine cylinders, crankshaft journals, transmission bores, piston pins, and valve guides — 100% in-process inspection at production speed.
Aerospace & Defense
Turbine blade platform IDs and actuator bore diameters, with NIST-traceable documentation supporting AS9100 and NADCAP systems.
Medical Devices
Implant bores, surgical instrument IDs, catheter and syringe OD — with SPC output for 21 CFR Part 11 records.
Bearings & Compressors
High-volume ID/OD inspection where repeatability and speed are critical.
Oil & Gas
Subsurface pump-barrel gaging with the SR1-TR oil-well configuration.
Why WESTport
- ISO/IEC 17025 accredited, NIST-traceable. Tooling and masters are manufactured and certified in our own climate-controlled laboratory.
- Compatible with every major system. WESTport plugs, rings, snaps, and comparators interchange with Mahr/Federal, Edmunds, Sheffield, GAR, Universal Gage, and Western Gage — upgrade a readout or replace a worn component without changing your setup.
- In-house calibration & repair. We recertify and rebuild air tooling and masters with a 5–7 business day turnaround on most items.
- Made in the USA since 1989. Precision-ground and hand-lapped for accuracy, surface finish, and wear life.