Measuring a bore under 0.100″ (2.54 mm) is where mechanical bore gages run out of room. Air gaging doesn't. A small air plug measures with jets of air instead of contact points, so nothing touches the bore, nothing wears, and chips and coolant are blown clear as you measure.
We build small diameter air plugs from 0.059″ (1.5 mm) to 0.100″ (2.54 mm), and have made specials as small as about 0.038″ (0.97 mm).
Request a quoteCall (815) 242-0027
At a glance
| Bore sizes | 0.059″–0.100″ (1.5–2.54 mm); specials to about 0.038″ (0.97 mm) |
|---|---|
| Repeatability | 0.000008″ (0.0002 mm) |
| Measuring range | Narrower than larger plugs; on the smallest sizes about 0.001″ (0.0254 mm). Contact us for your size. |
| Price | From about $1,500 at 0.059″. Smaller sizes cost more; our smallest specials, around 0.038″, have run about $2,500. |
| Readouts | Air Gage Pro stations and Metro M5 displays |
What's different about small bores
- The measuring range is smaller. The jets in a small plug are tiny, so the plug measures over a narrower band than a larger probe. On the smallest sizes it may be about 0.001″ (0.0254 mm). Repeatability stays excellent; your tolerance just needs to fit inside that range. Send us your bore size and tolerance and we'll confirm what's achievable.
- Air supply matters more. Small jets clog more easily, so clean, dry, filtered air is essential. See our air supply guide.
- Blind holes are possible, with limits on how close to the bottom you can measure. See how close to the bottom of a blind hole an air gage can measure.
- Small air rings aren't practical at these sizes. For small outside diameters, ask us about other options.
How to order
Call (815) 242-0027 or email info@airgaging.com. Need a larger bore? Price air plugs online, or see custom air gaging.
FAQ
What is the smallest bore you can air gage?
Our standard small diameter range starts at 0.059″ (1.5 mm), and we've built specials down to about 0.038″ (0.97 mm).
How accurate are small air plugs?
Repeatability is 0.000008″ (0.0002 mm). The measuring range is narrower than on larger plugs; on the smallest sizes it can be about 0.001″ (0.0254 mm).
How much does a small diameter air plug cost?
From about $1,500 at 0.059″. Price rises as the size gets smaller; our smallest specials, around 0.038″, have run about $2,500. Send us your bore size and tolerance for an exact price.
Do you make small diameter air rings?
Not at these sizes. Contact us about other ways to measure small outside diameters.