Bore Gage w/ Setting Ring - What is it used for?

[Bob_M]

Simple question I think, but I don't know who else to ask besides my fellow Covers...

We have a Bore Gage w/ Setting Ring (see attached picture) that is due AGAIN for calibration/verification but has not been used in the last year. (I probably won't send it out unless our tooling department has a use for it). My question is what is this gage used for? My best guess is its a limited range ID micrometer...

Description: Bore Gage w/ Setting Ring
Manufacturer: Bowers / Fowler
Model: 1.74970" Class XX
Serial: NA
Range: 1 1/2" - 2"

Also I personally don't know how to use or adjust this type of gage. Can any one provide info/tips/websites on how to use/adjust/change over this type of gage?

Thanks Bob M

 

[Jimmy Olson]

In a nutshell, yes, a bore gage is used for inside diamter measurements. The advantage is that a bore gage is typically more accurate then a micrometer.

As far as using and adjusting the gage, it's relatively simple. I have some procedures at home that I will look through and get something for you.

 

[Mike S.]

A bore gage is basically a micrometer for holes -- more accurate typically than calipers. Typically has resolution of +/- .0001". Stick it in the hole, rotate the dial until the 3 fingers contact the walls of the hole, and read the dial like a micrometer. Great for round holes -- just watch out if the hole is eggy. If you might rarely use it you might consider putting a long cal. cycle on it -- like 2 or 3 years. Just watch for rust or impact damage -- otherwise, if it is rarely used, does not get dropped, impacted, or rust, it should hold cal. very well. In fact, I rarely use mine and only have my setting ring calibrated every 2 years and do the cal. of the gage itself on my own against the ring (before each use) and never had either the gage or ring out of cal in over 4 years.

 

[Bob_M]

A bore gage is basically a micrometer for holes -- more accurate typically than calipers. Typically has resolution of +/- .0001". Stick it in the hole, rotate the dial until the 3 fingers contact the walls of the hole, and read the dial like a micrometer. Great for round holes -- just watch out if the hole is eggy. If you might rarely use it you might consider putting a long cal. cycle on it -- like 2 or 3 years. Just watch for rust or impact damage -- otherwise, if it is rarely used, does not get dropped, impacted, or rust, it should hold cal. very well. In fact, I rarely use mine and only have my setting ring calibrated every 2 years and do the cal. of the gage itself on my own against the ring (before each use) and never had either the gage or ring out of cal in over 4 years.

Thanks for the details. We don't use it for production. Our tooling guy MIGHT use it rarely upon return/rebuild of a die, but I don't think so. As you can see in the picture the ring is still sealed.

Do you use the ring to "zero the gage" or is it just included to calibrate it in house? Like a master block for a 1-2" micrometer?

Edit:
We have some VCI bags and Paper (rust inhibotor) that I have started to use to seal some of the unused mics and smaller gages. So at the moment we don't have rusty equipment.
(We use to have 2 guys that had severe amounts of "acid" in their sweat and could rust a gage overnight if it had not been wiped down after use).

 

[Jimmy Olson]

Do you use the ring to "zero the gage" or is it just included to calibrate it in house? Like a master block for a 1-2" micrometer?

The setting ring is meant to set the refernce point for the bore gage and should be used each time the gage is used. In your case the setting ring would give the gage a reference point of 1.74970 inches and then your measurements would be based on that.

 

[Mike S.]

Personally, I use the calibrated ring to calibrate my gage with each use. Never had a problem doing that.