Barrel Wall Thickness Readings

[MD*GSP]

If someone wanted to make a really, really nice gage for measuring wall thickness, there are woven phenolic materials (rods) available that are super rigid and would possibly suffer little to no flex when used. Further, a notch could be cut on the end of the rod that would allow various screw-in indicator tips to be used instead of a ball on the end which would allow for very accurate measurements of pits or other irregularities in the bores.

A gage made like that would be a bit spendy, however as they say, the right tool for the job is priceless. Here's a picture of various tips that could be used on the end of the rod. I think tips like these are what Brian's referring to..

[Dean Romig]

Originally Posted by Scot Cardillo

If someone wanted to make a really, really nice gage for measuring wall thickness, there are woven phenolic materials (rods) available that are super rigid and would possibly suffer little to no flex when used. Further, a notch could be cut on the end of the rod that would allow various screw-in indicator tips to be used instead of a ball on the end which would allow for very accurate measurements of pits or other irregularities in the bores.

A gage made like that would be a bit spendy, however as they say, the right tool for the job is priceless. Here's a picture of various tips that could be used on the end of the rod. I think tips like these are what Brian's referring to..

I especially like the one at the 7 o'clock position.





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[MD*GSP]

Originally Posted by Dean Romig

I especially like the one at the 7 o'clock position.





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Yep, that one and the one at six o'clock could really get down into pits well. The tips at 4 & 7:30 mimic the 'ball' that appears to be on most gages. Having various options would be a nice feature built into a purpose built gage like these.

[edgarspencer]

I considered using a replacement dial indicator tip, which would have required milling a flat on the rod, sufficient such the the dimension from tip-to- back of rod was less than .550”. The whole reason for making the new rod was to measure 28 gauge barrels. Damn tips are more expensive than Harbor Freight dial indicators.
As John Hosford showed in his video, aligning the indicator tip, to the ball is delicate; more so, the smaller the inner tip.
Without question, a finer tip inside the ball will more accurately measure bore pits, however I didn’t anticipate doing barrel evaluations on guns for others, as much as I wanted something for my personal use. I really don’t buy so many guns, and of questionable pitting to offset the smooth needle characteristics given with the .500” diameter ball

[MD*GSP]

Originally Posted by edgarspencer

I considered using a replacement dial indicator tip, which would have required milling a flat on the rod, sufficient such the the dimension from tip-to- back of rod was less than .550”. The whole reason for making the new rod was to measure 28 gauge barrels. Damn tips are more expensive than Harbor Freight dial indicators.
As John Hosford showed in his video, aligning the indicator tip, to the ball is delicate; more so, the smaller the inner tip.
Without question, a finer tip inside the ball will more accurately measure bore pits, however I didn’t anticipate doing barrel evaluations on guns for others, as much as I wanted something for my personal use. I really don’t buy so many guns, and of questionable pitting to offset the smooth needle characteristics given with the .500” diameter ball

The tips would be the cheaper part of the endeavor b/c I'm thinking they would require modification to make them work (ie: the .55 dim you mentioned). It would take a little fine machining to make the working end of the gage work-out just right.

The tips in the photo are Starrett but that's only b/c I buy Starrett everything. There are cheaper alternatives through company's like Enco etc. Also, if one did want to stick with Starrett tips, they can be purchased individually.