Economical Alternative to Bore Gage Setting Rings

[erikmannie]

Also called Smooth Bore Ring Gages, most Bore Gage Setting Rings are out of my price range! The Ringmaster brand is almost affordable to me. There is a used 2.000” one for $82.00 on eBay.

I just bought four Shars inside micrometers, and the 0.2-1.2” and 1-2” both came with such a gage. It sure was nice to test out these inside micrometers as soon as I opened the boxes.

The 2-3” and 3-4” inside micrometers did not include such a gage. I almost always check the zero on my micrometers before I take a measurement in the shop. I would like to have something in these ranges to check the larger inside micrometers.

I saw in a Blondihacks YouTube video where she used the ID of a bearing in order to demonstrate the use of telescoping gauges. She pointed out that a bearing is precision made with a smooth finish.

So is a bearing an acceptable alternative to a Bore Gage Setting Ring? Bearings are pretty inexpensive. One could possibly just buy and utilize an inner race.

One could also use a gauge block (e.g. 2.000”) to get a known distance on a micrometer, lock the micrometer, and then measure the distance between the anvils of the outside mic with the inside micrometer. Of course, this could risk abusing the outside mic (it certainly wouldn’t do it any good pushing against the anvils of a locked micrometer).

Any other ideas on an economical alternative to smooth bore ring gages? Maybe a good DIY project?

 

[benmychree]

One never trusts an inside micrometer reading, they are (nearly) always checked against an outside micrometer or other length standard.

 

[erikmannie]

One never trusts an inside micrometer reading, they are (nearly) always checked against an outside micrometer or other length standard.

So I should use a telescoping (snap) gauge and an outside mic? I do have 1”, 2”, 3”, 4” and 5” standards (they came with the micrometers). I also have a Shars 81 piece gauge block set.

I don’t imagine that it is a recommended practice to put an inside micrometer in between the anvils of a locked outside micrometer and turn the ratchet of the inside mic. This sounds like the definition of abuse.

My inside micrometers also have a lock. If it were not abusive, it would be interesting to use the outside micrometer to measure the distance between the anvils of the inside mic. But then I would be once again ratcheting on a locked micrometer. Seems like a terrible idea for a few reasons, not the least of which is threatening to scratch the micropolished finish on the carbide anvils.

 

[mmcmdl]

Get yourself a cheap set of gage blocks . They have many uses .

 

[benmychree]

So I should use a telescoping (snap) gauge and an outside mic? I do have 1”, 2”, 3”, 4” and 5” standards (they came with the micrometers). I also have a Shars 81 piece gauge block set.

I don’t imagine that it is a recommended practice to put an inside micrometer in between the anvils of a locked outside micrometer and turn the ratchet. This sounds like the definition of abuse.

The procedure is to take the measurement with your inside mike or telescoping gauge, then measure it with your micrometer, adjusting it onto the gage carefully until snug contact is made, then visually determine size from reading the mike.

 

[erikmannie]

Get yourself a cheap set of gage blocks . They have many uses .

I just happened to have bought a Shars 81 piece B Grade gage block set for $92 this afternoon, 100% of the revenue from my garage sale.

Does anybody ever (carefully!) clamp a gage block in their mill vice, and then measure the distance between the vice jaws with an inside micrometer?

 

[mikey]

One could also use a gauge block (e.g. 2.000”) to get a known distance on a micrometer, lock the micrometer, and then measure the distance between the anvils of the outside mic with the inside micrometer. Of course, this could risk abusing the outside mic (it certainly wouldn’t do it any good pushing against the anvils of a locked micrometer).

Any other ideas on an economical alternative to smooth bore ring gages? Maybe a good DIY project?

Erik, I don't see a problem using an external mic that is set to a known dimension to check your internal mic. All you need to do is touch the tips to each other; you do not need to use the ratchet or friction thimble. I do this all the time when reading a bore with telescoping gauges and I can tell you that when I use a ring gauge to set the telescoping gauge, it is accurate to within a tenth or less.

 

[erikmannie]

Erik, I don't see a problem using an external mic that is set to a known dimension to check your internal mic. All you need to do is touch the tips to each other; you do not need to use the ratchet or friction thimble. I do this all the time when reading a bore with telescoping gauges and I can tell you that when I use a ring gauge to set the telescoping gauge, it is accurate to within a tenth or less.

Helpful. So you have ring gauges? How many do you have?

 

[mikey]

Just three now. I gave a few away over the years. They are enough to suit my small bore gauges and telescoping gauges and it is more to keep my technique in practice before I bore a hole.

 

[benmychree]

I just happened to have bought a Shars 81 piece B Grade gage block set for $92 this afternoon, 100% of the revenue from my garage sale.

Does anybody ever (carefully!) clamp a gage block in their mill vice, and then measure the distance between the vice jaws with an inside micrometer?

Gage blocks should NEVER be clamped in anything (such as a mill vise) other than clamps designed to clamp them together in a stack with gage block accessories for measurement purposes. Other than using them to set a sine fixture in a stack, gage blocks are not very useful for general shop use without a set of accessories. They are not very convenient for micrometer setting as compared to micrometer standards due to the fussyiness in getting them parallel with the micrometer anvils; micrometer standards, having sphereical ends eliminate that problem.