Tips and Tricks for Setting A Dial Bore Gauge

Dial Bore Gauge Setting With A MicrometerThe Techxperts™ here at Goodson frequently get questions about how to properly set a dial bore gauge so we decided to devote this edition of Tech Notes to the basics and some tips to make it easier.

Setting a dial bore gauge is a simple concept.

  1. Set a micrometer to the size bore you will be testing
  2. Set up the dial bore gauge with the extensions necessary for the bore diameter
  3. Place the bore gauge between the micrometer’s spindle and anvil
  4. Rock the dial bore gauge back and forth and side to side in the micrometer.
  5. Note the minimum reading and zero the dial indicator to that reading

Sounds simple, doesn’t it? With the proper tools it is.

We’ve found that one of the more difficult ways to set a dial bore gauge is manually. You’ve probably done this – you hold a micrometer in one hand and the dial bore gauge in the other. Sounds simple, but it gets pretty tough to zero the dial reading when both of your hands are already busy. All you need is a third hand!

Since most of us aren’t likely to grow a third hand, we need to find an alternative. Machinists, being the inventive folks they are, have come up with some tricks.

Most shops have a vise on the bench that can be used to hold the micrometer steady. Just be sure to wrap the mic in a shop towel or use a vise with rubber pads so that you don’t damage the mic. This simplifies the process since your vise is acting as that third hand. You’ll still need to do a bit of a balancing act to zero the dial because the round point on the gauge extension is going to want to slide off of the micrometer spindle.

Slip a short piece of 1/4" ID hose over the mic spindleA quick (and inexpensive) trick to make this a little easier is to slip a short piece of 1/4” ID hose over the micrometer spindle. Let it extend just enough to let the tip of the extension slip inside, stabilizing the whole assembly. Now this is not going to hold the dial bore gauge all by itself but it will make it harder for the extension and the spindle to slip apart. Don’t worry, this little piece of hose won’t affect the reading of the micrometer or the dial bore gauge.

Another quick tip that came from an old machinist is to mount the dial bore gauge in the vise and apply the micrometer. In this case, you’ll be rocking the micrometer instead of the dial bore gauge, but you might find this works better for you. Again, be sure to protect the shaft of the dial bore gauge from damage when you mount it in the vise. This technique will also work with a Micrometer Stand.

MIC-FIX Micrometer Stand set upDesigned on a similar principle is the Micrometer Stand (MIC-FIX), commonly called a “third hand”. This tool is designed to hold just about any type of micrometer (up to .500” thick” in its rubber padded jaws. Tighten the knob so it’s snug, but not too tight and the micrometer will stay put. Micrometer StandAn advantage of using the stand is that you can adjust the angle of the jaws to make it easier to see the micrometer and work with the dial bore gauge. The jaws in the Goodson model adjust about 30° in either direction.

A step up from these two options is to use a Dial Bore Gauge Setting Fixture. Goodson offers one that was designed to fit most popular bore gauges including Mitutoyo, Phase II, Fowler and Peacock. This setting fixture won’t fit Sunnen® gauges, but Sunnen® offers its own setting fixture which is also available from Goodson. Both setting fixtures have built in micrometers and standards so you can set up for bores from 2” to 6” diameters.

Goodson Dial Bore Gauge Setting Fixture (DBG-FIX  Sunnen Dial Bore Gauge Setting fixture

Setting Fixtures work on the same principle as the vise and the micrometer holder, but they are dedicated specifically to setting up dial bore gauges. Before you can use the fixture to set up your bore gauge, you’ll need to set up the setting fixture. For those instructions, download or view the product instructions.

You may also want to check out the step-by-step instructions on assembling a Dial Bore Gauge.

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  • Rich - September 12, 2019

    I love this post and i forward this to some of m customers. Could you make a similar article for a

  • Erik Shepard, Goodson Tools & Supplies Tech Service Manager - December 10, 2018

    Hello Tanaji, to select the proper anvil you will want to pick the anvil closest in size to your bore diameter. You may have to use the spacers that come with the dial bore gauge to get as close as you can. The size does not have to be exact but should be very close so you have some room to work with in the pre-load of the dial bore gauge. Then zero the dial bore gauge with either a micrometer or a dial bore gauge setting fixture to your bore size.

  • Tanaji - December 10, 2018

    Please tell me how to select the proper anvil for particular dimensions eg- to measure dimensions of 61.5 +/-0.01 mm

  • Janet Tapp - August 09, 2018

    Hi Charles, thanks for contacting us about this blog post and the product you’re trying to find. I have passed your request on to our technical department so someone should be contacting you soon.

  • Charles Sanders - August 09, 2018

    Can you design/make/supply a special purpose Dial Gauge Setting Fixture for diameters over 8"?
    We use Sunnen setting fixtures up to 8" but over this have to revert to micrometers and as pointed out in your excellent article “tips-and-tricks-for-setting-a-dial-bore-gauge” this isn’t easy, especially so when trying to set 30" diameter gauges!

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