Bore Gauge

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Vietti

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I have been using a telescoping bore gauge for a while but don't trust my ability for accurate repeat measurements. I am looking for a bore gauge in the range of 0.7" to 1.375". Quite a few options on Amazon etc. for around $100. Not willing to pay for premium quality, $300 versions. Can anyone suggest a decent quality at an affordable price bore gauge??
 
Practice practice practice. Otherwise, most bore gauges for that range of sizes need setting rings if you want to know true size. You can set them to a micrometer, but that puts you back to feel and careful technique to find the "high spot" by wiggling the gauge back and forth.
 
I have been using a telescoping bore gauge for a while but don't trust my ability for accurate repeat measurements. I am looking for a bore gauge in the range of 0.7" to 1.375". Quite a few options on Amazon etc. for around $100. Not willing to pay for premium quality, $300 versions. Can anyone suggest a decent quality at an affordable price bore gauge??
I have own bore gages in pass
I when back to telescope gauge for setting ball bearing.
I found was easier and I could read to 0.0001" on mic. I did thousands of 6203 and 6205 ball bearing.

Dave
 
Bore gages take some time to wring out your own bugs . I know the ones I have are more accurate than I am . I do recall reading somewhere that ya should be able to change the indicator with a more accurate one if desired .
animal
 
In my past life I used to develop tooling for production operations and would buy dedicated bore gauges for products we produced. They are expensive if you want good accuracy and repeatability. For my current needs, I use telescoping gauges and have had very good success with them. As stated by rklopp, you do need to practice a bit and you will develop accuracy and consistency. Review your technique and refine if necessary and you will find they are fairly quick to use and you will have very good repeatable accuracy without spending a bunch of money.
 
John,

I have a Fowler 0.7" to 1.4" bore gauge I bought on sale for a low, low $100+. I was not particularly thrilled with the cheap construction of the case and the limit tabs on the dial, but it does give me repeatable measurement accuracy in the order of a tenth or two. The pressure on the wall contact points is very high, so I'm always a little concerned about scratching or marring the bore itself.

It's true that a good telescoping gauge set can be that good, but it certainly demands skill and patience to get that accuracy, and on a bad day I can still make mistakes of more than a mill in "feeling' the telescoping gauge. I still use both.

Don
 
Some decent deals can be found on Ebay for tri-mike bore gauges, though you will need a known good ring gage to verify it.
 
A much cheaper method is one I have taught machinists for years .
Use a Good (!!!!!!) adjustable parallel- one that has good edges-no dents and is parallel
Insert it in the bore and expand it. You can now read the bore diameter Cross-corner
with your normal mike.

This method also shows taper bores or coke bottle bores if it rocks
It allows using the same mike to be used for fits !
Rotating it between measurements checks for egg shaped bores
This may or may not work for you or in closed bore holes , just try it.
Rich
 
Thanks, Rich. I always forget that technique. Somewhere I've heard of adjustable parallels with cylindrical faces, but I don't think I've ever seen them for sale.
 
I when back to telescope gauge for setting ball bearing.
Same here....also, if doing bearing recess measurement to do it with guage vertical.
One will notice that good quality telescoping gauge, such as Moore and Wright (original) has just one leg sprung.
That plus the "nip" required to lock the guage in the bore is ever-so-light as compared to many many others (yes, tried the latter and gave them away).
Then measure result with outside micrometer.
Works spot on every time for me.
 
I was taught this method for using telescoping gauges by my first German Immigrant foreman.
People try to put the gauge in and then tighten and pull it out.

I was taught to wiggle it back and forth in the bore so it can find center, then slightly tighten the gauge and then roll it through. Hope I am explaining it well enough. I also found that cheap telescoping gauges don't work very well. My go to set is a Starrett set. They will make very accurate measurements.
 
I was taught this method for using telescoping gauges by my first German Immigrant foreman.
People try to put the gauge in and then tighten and pull it out.

I was taught to wiggle it back and forth in the bore so it can find center, then slightly tighten the gauge and then roll it through. Hope I am explaining it well enough. I also found that cheap telescoping gauges don't work very well. My go to set is a Starrett set. They will make very accurate measurements.


Part of what I found challenging was developing 'the feel' with the telescoping gauge.
Sorta like with a vernier - - - with out a good 'feel' an ID will be wrong (either not exactly at the diameter or else dragged big by the use of too much pressure).
Maybe it was just me but I had to learn the sensitive careful feel of the tool.
Dunno if that's just experience - - - ymmv.
 
A much cheaper method is one I have taught machinists for years .
Use a Good (!!!!!!) adjustable parallel- one that has good edges-no dents and is parallel
Insert it in the bore and expand it. You can now read the bore diameter Cross-corner
with your normal mike.

This method also shows taper bores or coke bottle bores if it rocks
It allows using the same mike to be used for fits !
Rotating it between measurements checks for egg shaped bores
This may or may not work for you or in closed bore holes , just try it.
Rich
Like I said, There is a lot of talent people on here. Thank you for that info.
 
The method I had been taught to by our QC guys and is, I believe the same as described by mnay above. A little tutorial is detailed if you go to this link:

 
I have been using telescope gauges for years and "practice makes perfect."

Abom79 on YouTube discusses them and I have adopted his techniques with good results:



With budget issues, I have spent the money that would have been spent on the three-point gauges on other things. I have a Starrett 4-pc set as the best, but also have the "import specials" to get the larger-capacity ones I seldom use.

In some cases, I take the time to turn up go/no-go gauges for the specific project. That won't find egg-shaped or tapered bores, but it will help if you have a lot of checking to do in a certain size.

--ShopShoe
 
My go to set is a Starrett set. They will make very accurate measurements.
That was the brand of the ones I gave away as junk.

Problem as with many things , some wouldn't know the difference.
 
I was taught this method for using telescoping gauges by my first German Immigrant foreman.
People try to put the gauge in and then tighten and pull it out.

I was taught to wiggle it back and forth in the bore so it can find center, then slightly tighten the gauge and then roll it through. Hope I am explaining it well enough. I also found that cheap telescoping gauges don't work very well. My go to set is a Starrett set. They will make very accurate measurements.
I agree
Most of my measurements are Starrett very smooth to use. I Starrett mic to 16" od

There is a learning curve on taking measurements to 0.000,1

Dave
 
I never saw telescopic bore gauges besides pictures or Youtube.
Everybody in the real world seems to use Bore gauges with a dial indicator, mostly made by a known Japanese brand. (I guess there are regional differences)
3 point internal Micrometers can quickly cost a fortune. Someone told me that he is not a fan, because they will not reveal if a bore is oval.
I guess the best option for budget is to try to find a used gauge with a dial indicator an then get some accurate ring gauge. Possiby just a ball bearing of known tolerance.
 
Last edited:
I never saw telescopic bore gauges besides pictures or Youtube.
Everybody in the real world seems to use Bore gauges with a dial indicator, mostly made by a known Japanese brand. (I guess there are regional differences)
3 point internal Micrometers can quickly cost a fortune. Someone told me that he is not a fan, because they will not reveal if a bore is oval.
I guess the best option for budget is to try to find a used gauge with a dial indicator an then get some acurate ring gauge. Possiby just a ball bearing or known tolerance.
Remember most like the 3 point are aids even the bore gauge in most case is aid .
When start in machine work you did see 3 point and bore gauges was very hight price.

I tried a bore gauge for my employee's it did not work out .
It faster and easier for me go just check work. We did over 10,000 ball bearing seats a year.

Dave
 

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