Measurement of nuts and screws

[mkpash]

es and surface finish.

And it is near impossible to gauge any thread with only one gauge.

what about a tri-roll gauge? is it any better than caliper guage?

 

[mkpash]

what I'd do is measure enough of the bolts so you can see where they are within the pitch diameter tolerance and the distribution spread. I'm reasonably certain you'll find a very small spread but close to the tolerance limit.

Great idea, before rejecting any of the bolts with thread caliper, i will cross check with thread parallels the pitch dia on three different locations of the thread (top, middle,bottom) and get an average. Then i will make a distribution to see where it lies compared to the nominal..Hope this will help in investigating the issue..

 

[michiganbuck]

what about a tri-roll gauge? is it any better than caliper guage?

I have never used a try roll gauge, Gordon would know more about that than I. At the big shop we had ID and OD thread masters .go and no go gauges. shadow graphs. and just about everything you might think of. I was not an inspector but they would often ask me to make a gauge some they wanted to within a few millionths. 50 millionths is half a tenth so not that close for a grinder hand.
Don't think they ever asked me to make a tread gauge because there are few one can make in the grinding room.

 

[Gordon B. Clarke]

what about a tri-roll gauge? is it any better than caliper guage?

Much better but also much more expensive. You'll also need a calibrated master thread for the tri rollers.

Measure with wires, find the spread and where it is. That'd take max 30 minutes and I'm sure the time offered by all on this exceeds 30 minutes.

Even if you agree with your supplier will your customer agree with you?

MEASURE A GOOD SIZED SAMPLE. It's what you should have done from the start. If you can't find someone that can.

Use wires like this and a good micrometer.

 

[Chip Burns]

Is your facility ISO certified? They seem to be the last word in the world of QC. According to everything that I have learned from fifty years of machining things, the pitch diameter is the truly functional part of two mating threads.
Another thing that may cause issues is the flank angles in the gauges. We’re both/all gauges involved, made in the same relative time period by the same gauge manufacturer?

 

[guest]

Just trade gages with the supplier.

 

[Delw]

Hi RKlopp,

Supplier is using the same methodology as we are using ->Thread Calipers and Plug Gauges
We did make a video as you mentioned. Video clearly shows that the NOK parts measured on our caliper are OK on supplier's caliper
Both having been certified to UKAS by the same company.
I am inserting the video here. Blue one is supplier gauge, black one is ours.

Now i don't know how to take this further..should we change our measuring methods?

Regards,
Mustafa

I watched this video a few times something didnt look right., the black gage which is yours looks like a piece of Garbage pulled out of a scrap barrel. the blue one your customer is using looks decently clean. in reading some of your replies and watching the video I am kinda thinking you dont know what your doing and have a very messy inspection dept. and dont keep up on calibrations or taking care of precision gages.

that leads me to believe your customer is correct and your wrong

 

[Chip Burns]

Please allow me to ask if there happens to be a hardened and ground master plug gauge that has been certified by some accepted standards, for the sole purpose of setting and periodically checking all of the gauges involved in this problem?
This may be like a shop with twenty machinists using twenty different micrometers that have not been calibrated to the “same size” inch trying to make parts to close tolerances.
As has been mentioned earlier and shown in the video, you have at least two gauges that are not very close to being identical. Without a setting master, can never determine which one is correct.

 

[michiganbuck]

One possible solution might be to see if the customer's check/reject is predominantly on the big or small limit of thread class gauging..If then set your gauge .001 / .0002 (or what) to favor their checking criteria. Still, your parts would be in gauge to anybody's gauging..just a tad tighter at that end of the scale.

Perhaps in a spread of .002 you are in dutch with a discrepancy of one-tenth.

 

[jccaclimber]

Zombie thread alert.

 

[???]

Apart from the calibrated Thread Calipers you're using, you might wanna try out tools like Thread Parallels contacts or Thread Pitch gauge for even more precise measurements. And for the nuts, using a calibrated Go/NoGo plug gauge should definitely be a valid method of inspection. To convince your supplier, stress the importance of quality and reliability in construction materials. You could also share your experiences and findings with other professionals on this forum to gather more support for your inspection methods. I know this is an old thread, folks, but I just wanted to share my thoughts and one helpful rec. Here's the shop where I always buy screws https://www.scrooz.com.au/. Just a suggestion, not an ad. Share your recs, guys.

Bullshit you register and immediately post a link in a dormant thread to a company located in a country that 99.9 percent of people on this forum would never buy anything from. Either you think forum members are stupid or you are as thick as two short planks.

 

[jccaclimber]

Bullshit you register and immediately post a link in a dormant thread to a company located in a country that 99.9 percent of people on this forum would never buy anything from. Either you think forum members are stupid or you are as thick as two short planks.

The spam post has been deleted, your post is the only reference to it now. Can you clear that out?