Opposed two-jet
Production starting point for comparative outside diameter across one axis.
Know the limit A two-jet ring can miss a three-lobed form because the opposed readings may average together.Air ring gauges for shaft and OD measurement
Custom pneumatic ring tooling for fast comparative measurement of precision shafts and outside diameters.
Understand the air gauging principle
MEASUREMENT TARGET
OD SHAFT CONFIGURE TO DRAWING
Measure the shaft without contact pressure
A shaft passes through the ring while regulated air exits calibrated jets towards its surface. Changes in jet-to-shaft clearance alter airflow or back pressure, which a compatible comparator converts into a comparative outside-diameter reading.
Not a stand-alone gauge A complete station also needs a compatible comparator or digital readout, clean regulated air, matched setting masters, correct tubing and reliable part location.
Configure the complete measuring chain
- Define the shaft Nominal outside diameter, tolerance, measured land, adjacent shoulders, chamfers, fillets and surface condition.
- Select the tooling Jet count, measuring planes, central or offset position, shoulder reference, mounting and wear protection.
- Match the system Readout range, setting masters, filtration, tubing, loading method, fixture and required data outputs.
Choose the sensing layout for the feature
Jet count and measuring-plane location determine what the system can reveal. The component drawing and inspection method should be agreed before the ring, masters and readout are released for manufacture.
Three or multiple jets
Consider when lobing, circumferential averaging or a defined form response is required.
Confirm the method Jet count, angle and pneumatic response must be matched to the expected part geometry.Multiple measuring planes
Separate diameter circuits can compare locations along the shaft for taper or selected profile checks.
Plan the station Readout channels, axial spacing, part location and master strategy are configured together.Main features
- Opposed two-jet sensing is the standard starting point for comparative outside-diameter measurement
- Three-jet or multiple-jet layouts can be reviewed for lobing, averaging or application-specific form checks
- Single-plane or multiple-plane circuits can be configured for size, taper and selected form evaluation
- Shoulder-referenced, offset-jet and fixture-mounted arrangements can control the measuring location
- Wear-resistant sleeves or contact surfaces can be reviewed for hardened components and production duty
- Working clearance, jet geometry and pneumatic range are matched to the shaft tolerance and selected readout
Applications
Application specifications
| Measurement method | Pneumatic comparative outside-diameter measurement |
|---|---|
| Standard sensing arrangement | 2 opposed air jets |
| Special sensing arrangements | 3 jets or multiple jets; application dependent |
| Measuring layouts | Single plane, multiple plane, central or offset; drawing dependent |
| Reviewed reference envelope | Ø1.5–150 mm; AccuTouch supply range requires confirmation |
| Mastering | Matched low and high setting masters normally required |
| Part location | Hand-held, shoulder-referenced or fixture-mounted by application review |
| Accuracy and working range | Complete-system, clearance and application dependent |
Configuration guidance is based on published engineering reference information for this product category. Final AccuTouch diameter, jet layout, measuring plane, pneumatic range, readout compatibility, masters and accuracy are confirmed only in the written quotation.
Included
- Configured air ring gauge as defined in the approved written quotation
Configuration options
- Two-jet, three-jet or multiple-jet sensing
- Single-plane or multiple-plane measurement
- Shoulder reference or offset measuring plane
- Hand-held, bench-mounted or fixture-integrated arrangement
- Loading aid or part-location fixture
- Wear-resistant sleeve or surface treatment
Frequently asked questions
What information is needed to configure an air ring?
Share the component drawing with nominal outside diameter, tolerance, measured land length, adjacent shoulders, chamfers, fillets, material, hardness, surface finish and inspection rate. Also state whether size, taper, ovality or lobing must be evaluated and identify the existing readout, if any.
Does the air ring need a separate readout?
Yes. The air ring is the pneumatic sensing tool. It must be matched to a compatible air comparator or digital gauging unit, its operating range, tubing, masters and clean regulated air supply.
Can I buy it online?
Public prices and payment credentials are not configured. AccuTouch will confirm price, GST, configuration and delivery through a written quotation.
Why are low and high setting masters normally required?
Two known master sizes establish the pneumatic response near the working tolerance limits. The master separation must suit the component tolerance and selected readout range, so the masters, ring and comparator should be specified as one measuring system.
Can one air ring check diameter, taper and ovality?
One opposed jet plane provides a comparative diameter across one axis. Rotating the shaft can support ovality assessment, while two or more axial planes can compare diameters for taper. Lobing and other form conditions may require a different jet layout and an agreed evaluation method.
Will a two-jet ring detect a three-lobed shaft?
Not reliably. Opposed jets can average an odd-lobed form and show little change. If lobing is a known risk, state the expected process signature so a three-jet or multiple-jet arrangement can be reviewed.
How is the correct measuring position controlled?
The ring can be designed around a shoulder reference, offset measuring plane, loader or dedicated fixture. The chosen method must square the component and place the jets on the specified land without interference from chamfers, fillets or adjacent diameters.
What is the delivery time?
Air rings are manufactured to the approved component and system configuration. Lead time is confirmed after the drawing, jet layout, measuring planes, master sizes, mounting, wear protection and quantity are fixed. The written quotation or order acknowledgement provides the committed schedule.
How should an air ring be used and maintained?
Use clean, dry and correctly regulated air; keep the jets, bore and masters free from oil, swarf and dirt; avoid forcing or impacting the component; and store the ring protected from corrosion and damage. Follow the approved cleaning method rather than inserting hard wire into a jet.
What accuracy and measuring range can be expected?
The ring alone does not define total system accuracy. Jet clearance, readout range, master uncertainty, air quality, temperature, part location, surface condition and the evaluation method all contribute. AccuTouch confirms the usable range and acceptance criteria after application review.
Related engineering resources
Plan the complete measurement application
Use these guides, applications and tools to define the right gauging configuration.