Final Bore is under spec

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Cabbagestack
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Joined: Sun Jun 12, 2016 10:58 am

Re: Final Bore is under spec

Post by Cabbagestack »

Harold_V wrote: Thu Nov 16, 2017 1:55 am ...One hits size by chance if the exact measurement isn't known. That's why I asked how the dial bore was set. It may provide repeatable readings, but they may or may not be the actual size if not set by a ring. I've been embarrassed by that issue more than once in my life.

H
Harold,
What about setting a dial bore if you don't have the appropriate ring? Is there a good way to do it if you have gauge blocks? Or perhaps the appropriate micrometer ? Many of us cannot afford a bunch of rings. I have a few rings; but there are bound to be times they are not suitable for the job at hand. Thanks.

(I know this thread is a bit old -- but looking through it, I felt compelled to post the question here, as it seemed the best place; it is something that has been in the back of my mind for some time)
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Harold_V
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Re: Final Bore is under spec

Post by Harold_V »

A good way?
The only "good way" is with a ring. Any other method offers the opportunity for a gauge to be set off center, which alters the desired size. That's been my problem in the past, and I know of no way around it that is 100% reliable. I've used stacked gauge blocks as well as micrometers.

Some companies, Sunnen being one of them, offer setting fixtures. They hold the instrument in what is perceived to be proper alignment, so gauges can be set with reasonable accuracy. I strongly suspect that they would fail in critical situations, however. The error might be small, but there is likely some error by that system. Rings, properly applied (don't warm them with your hands, and make sure they are certified), are really the best possible approach. The problems are, who can afford the huge number of rings required, and how does one go about storing all those rings? It makes sense only in large operations. The home shop guy is likely restricted to trusting tools that are at his disposal, and learning to live with their minor limitations.

I welcome the thoughts of others.

H
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