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Extender Bore Gage Sets – 2 for 1

Selecting the correct dial bore gage for your application can be a challenging process as you want to purchase precision tools that you will be able to use on multiple jobs in the future as well. There are many factors you need to consider in finding the right bore gage: Range, accuracy, repeatability, graduations or resolution, and measuring depth. The two most popular ranges of dial bore gages offered by all the major gaging companies is 1.4-2.5” and 2-6”. Fowler High Precision had the brilliant idea of combining those two ranges into one bore gage kit and the Extender bore gage line was created.


  • Carbide anvils
  • Easy to read
  • Easily adjustable for bore measurement throughout the range
  • Self-centering
  • Insulated grip
  • Chrome plated handle
  • Includes removable posts and spacers
  • Includes extension holder and fitted case

The Extender Bore Gage Sets are essentially two bore gages in one and cover a range of 1.4-6.0”/35-160mm. Extender Bore Gage Sets are now being offered in three different graduations: .0005”, .0001” and .01mm as well as an electronic version with .00005″/.001mm resolution. This is the perfect bore gage for a home machinist or mechanic who needs to accurately measure bore dimensions. At HigherPrecision.com, we love the Extender series and highly recommend it to our customers who will be saving hundreds of dollars that they can use to purchase additional precision measurement tools. The extender dial bore gage sets are commonly calibrated with micrometers but Fowler also offers an affordable bore gage setting master kit for both inch and metric bore gages.

Fowler Bore Gage Setting Master Kits:

Extender Dial Bore Gage Sets:

  • 52-646-400 Extender Dial Bore Gage Set: 1.4-6.0″ (.0005″)
  • 52-646-500 Extender Dial Bore Gage Set: 1.4-6.0″ (.0001″)
  • 52-646-220 Extender Dial Bore Gage Set: 35-150mm
  • 54-646-401 Extender Electronic Dial Bore Gage Set: 1.4-6.0”/35-160mm

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