Checking ring gages

drgnrider · Aug 21, 2014

Checking Ring Gages with their appropriate Set Plug Gages. On a few, I am getting a "bind" a few threads after transitioning from the truncated-form to full-form.

Checking for bellmouth on the first few threads, the Ring Gage is solid, no wobble. It has the same amount of drag on the truncated portion, but then gets about the same distance on the full-form portion, regardless of which side of the Ring Gage starts, then starts to bind.

It appears to be something with the middle portion of the Ring Gage. I have looked at both gages, by eye, and do not see anything that would cause this. I have searched the internet and am not finding anything on this subject, any ideas what this might be and is it correctable or a failure of the gage?

Not wanting to reset them unless I have to, adjusting gages is a nightmare since we are ISO-9001 certified. :ack2:

Thanks.

cklapperich · Aug 22, 2014

have your set plugs been calibrated? By a certified calibration laboratory? recently?
Have both the set plug and the ring gage been thoroughly cleaned, and are free of dust and debris?

Do you seal the ring gages with wax to prevent tampering or adjustments?
It sounds to me like the ring gages need adjustment. Yes, it sucks. Yes, means writing NCs and all that, but such is life. An engineer will write an impact to product statement saying no kittens have been harmed and it will all be good.

cklapperich · Aug 22, 2014

drgnrider said:
I have looked at both gages, by eye

Try with a microscope.

drgnrider · Aug 22, 2014

cklapperich said:
have your set plugs been calibrated? By a certified calibration laboratory? recently?
Have both the set plug and the ring gage been thoroughly cleaned, and are free of dust and debris?

Do you seal the ring gages with wax to prevent tampering or adjustments?
It sounds to me like the ring gages need adjustment. Yes, it sucks. Yes, means writing NCs and all that, but such is life. An engineer will write an impact to product statement saying no kittens have been harmed and it will all be good.

Set plugs calibrated by A2LA lab. Cleaned… yes. Sealed… yes.

I tried to adjust one, but it didn’t fix the issue. It acts like it is bellmouthed on the first few threads; runs loose (spin it and it will do a few rotations), until the ring gage gets to the full-form section, then has the ‘drag’. :confused:

cklapperich said:
Try with a microscope.

I’d like one, better yet, an optical comparator, but I can’t even get the tools that have been obsolete since the 70’s and worn out since about ‘05 replaced without a fight. [Got $14K of the needed $51K done before they complained and put a stop to it!

]

cklapperich · Aug 22, 2014

oh come on, a microscope is like $100! I feel your pain on the budget issues though, its the same way over here - LOL read my posts on calibrating set plugs

troubleshooting:
(not meant to make you feel like an idiot, we all make dumb mistakes sometimes

)
Are you using a go set plug on a go ring gage?
Do the size, pitch diameter, class, all match? If the ring gage says UNC - 2B then the set plug needs to say UNC, and it needs to say 2A.

drgnrider · Aug 25, 2014

cklapperich said:
oh come on, a microscope is like $100! I feel your pain on the budget issues though, its the same way over here - LOL read my posts on calibrating set plugs

troubleshooting:
(not meant to make you feel like an idiot, we all make dumb mistakes sometimes )
Are you using a go set plug on a go ring gage?
Do the size, pitch diameter, class, all match? If the ring gage says UNC - 2B then the set plug needs to say UNC, and it needs to say 2A.

$100... Unfortunately, even trying to replace one of our 0-1 OD mics takes three signatures and about as many weeks, and, whether I send them the pieces or not, I still have to be ready to play 20-questions. :rolleyes5:

Not feeling like and idiot, you're not seeing what I am using, so you need to "trust, but verify"

Yes, the set gages are matched to the rings: "go", class, p.d., etc. I always pull the set gages, check everything, put them next to the ring gages on the counter, verify them again before I use them.

specfab · Aug 25, 2014

I'm not sure from your posted info whether you have multiple copies of the same thread gages that you are working with, or all gages are different. In any case, I have seen this kind of thing before, and the problem was in the plug. Some little ding that has magically appeared somewhere that is completely overlooked, or ignored because "the problem has to be in the ring".

specfab · Aug 25, 2014

Further to this:
You might want to do a sanity check on the pitch dia on the plug(s), with wires and a mic (or some other accurate method, just to see if there is wear on the first few full-form threads. They may have seen more use than the portion farther up the plug. Probably not highly likely, but if you eliminate all else...

drgnrider · Aug 26, 2014

specfab said:
I'm not sure from your posted info whether you have multiple copies of the same thread gages that you are working with, or all gages are different. In any case, I have seen this kind of thing before, and the problem was in the plug. Some little ding that has magically appeared somewhere that is completely overlooked, or ignored because "the problem has to be in the ring".

One set of each: Set Plug & Ring.

Troubleshooting made me look closer at the Set Plug, since it happened on both sides of the ring gage at the same place. Couldn't see anything by eye. The other place I was looking at is the middle portion of the ring, some sort of a build-up, (dirt or gaulding), but was unable to see anything there either.

My Set Plugs only get used about once per year and have been calibrated within the last 18-months, but I will check it with wires and see if the p.d. is still correct.

drgnrider · Sep 2, 2014

specfab said:
Further to this:
You might want to do a sanity check on the pitch dia on the plug(s), with wires and a mic (or some other accurate method, just to see if there is wear on the first few full-form threads. They may have seen more use than the portion farther up the plug. Probably not highly likely, but if you eliminate all else...

drgnrider said:
One set of each: Set Plug & Ring.

My Set Plugs only get used about once per year and have been calibrated within the last 18-months, but I will check it with wires and see if the p.d. is still correct.

Checked both Set Plug gages that I am having this issue with, both p.d.'s are within tolerance.

specfab · Sep 3, 2014

One of the mysteries of the universe, it appears. The only other thing I could suggest is to (maybe) try to blue up (or Sharpie, for a more casual endeavor, and thinner layer) the threads, and see where there is evidence of high spots. Might tell you something.

Paolo_MD · Sep 3, 2014

This is pretty dumb, but I'll mention it anyway...

Most likely you've already done it. However, I'd give a good cleaning with solvents at both rings and plugs, following with a wipe with a piece of shammy cloth.

My suspicion is that at some time they've been lubed with the improper oil.

Paolo

fpworks · Sep 3, 2014

possible wear on the ring gage?

drgnrider · Sep 3, 2014

specfab said:
One of the mysteries of the universe, it appears. The only other thing I could suggest is to (maybe) try to blue up (or Sharpie, for a more casual endeavor, and thinner layer) the threads, and see where there is evidence of high spots. Might tell you something.

I'll have look into that when I get past the remainder of my current backlog. [end of the month, all just mysteriously appear

]

Paolo_MD said:
Most likely you've already done it. However, I'd give a good cleaning with solvents at both rings and plugs, following with a wipe with a piece of shammy cloth.

My suspicion is that at some time they've been lubed with the improper oil.

Paolo

Yes, both have been cleaned with solvent, degreaser, and re-oiled.

The only people that oil these are me and my calibration predecessor! :angry:

Very few of the machinist's take care of the company tools, let alone their personal ones that they buy (have to do some cleaning on them in order to calibrate them). Trying to change this lackadaisical attitude, but the "higher-ups" don't care so why should the users? :ack2:

fpworks said:
possible wear on the ring gage?

Maybe... too much wear causing it to "twist"??? Maybe it's "growing"? Some of these have been here a number of years... :scratchchin:

might have to send them to the CAL LAB with the optical comparators....

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