Black Oxide Gage Pin Calibration Requirements

[cotton2007]

I am wanting a way to calibrate my gage pins in house without a super mic. Can I purchase a set of calibrated Black oxide gage pins and keep them in service without calibrating if I replace them once black shows to be worn. Thanks in advance!

 

[Eredhel]

Could you just make your gage pins reference only and then just measure them with calibrated calipers before using them?

Edit: Just realized what section this was in. I'm way out of my league here and doubt my suggest applies at all. Sorry!

 

[normzone]

I agree that checking them with a calibrated micrometer is a valid method of determining diameter, but what are these pins used for?

If they're used to check short holes you're okay, but if you're depending on them in long depths you might get bends in the oxide pins that will make the virtual diameter out while it still measuring in diameter at any given point. You could roll them on a surface plate and examine them in that manner.

It all comes down to what you're using them for. At one end of the spectrum you don't even need the oxide - at the other you may need dedicated sets in tenths.

And access and use tells all - in my experience the method that pins wear out is when the manufacturing crew gets access to them and uses them for deburring tools.

 

[cotton2007]

They will be used as a shop set to check holes during machining processes. I want a way to calibrate them without sending them out...any suggestions much appreciated!

 

[normzone]

They will be used as a shop set to check holes during machining processes. I want a way to calibrate them without sending them out...any suggestions much appreciated!

Yeah, these are the pins at greatest risk. They will be used to check holes on a regular basis, which leads to their being used as defacto deburring tools the first time they don't clear a hole being checked. Also hole depth is a factor - if the hole in question is .250 deep, that's a different issue than if it's an inch deep - pins get bent as well as worn.

What tolerances need to be held ? If it's a thousandth or two, it's a different issue than if it's all about tenths.

Assess the costs of replacement vs the cost of calibration. If it was me, and the situation was in thousandths, I'd not calibrate them - I'd use a micrometer, and maybe a surface plate to check them with periodically and then replace them when they showed wear signs. After a while you may learn how often to replace them and can consider just doing that.

Now if it's out into tenths, that's a different game.