Thread callout - M22 x 1.0-6H 0.100R Thread

[Kchnwtch]

Hello,
Have any of you ever seen a thread callout on a print that looks like this:

M22 x 1.0-6H 0.100R Thread

(We're wondering what they mean by 0.100R.)

We've contacted several of the tech people related to the job, and they've given us the runaround, finally telling us that we can make and certify our own gage to this callout. We'll eventually have the mating piece to test to, but we'd like to be clear before we start.

We want to make sure we're not missing some thread designation that we might not have seen before. I've done a lot of research in thread specs, including gov't specs, but I've not seen this.

Our theory is that they want a radius on the bottom few threads for strength, a radius of .100mm. Is that what you think, too?

Thanks for your help!

 

[Project Man]

Re: Help with thread callout - M22 x 1.0-6H 0.100R Thread

When you said "We've contacted several tech people related to the job." Does that mean you contacted the customer? Because, this is definitely a question you should be asking them.

 

[BoardGuy]

Re: Help with thread callout - M22 x 1.0-6H 0.100R Thread

As I remember it metric threads are classified [FONT=&quot][/FONT]as follows:

(Type)(Size) x (Pitch) - (Class) (Allowance) (Modifier)

I believe that "0.100R" relates to root radius. In this case modifier is indicating that the root radius of the thread must be inspected for conformance to this requirement. I would consult thread specification ANSI/ASME B1.13 or the international equivalent to verify that this is the correct interpretation.

 

[Project Man]

Re: Help with thread callout - M22 x 1.0-6H 0.100R Thread

In my old (25th edition) Machinery's Handbook it references ANSI B1.13M-1983, R1989 stating: r = External Thread Root Radius

 

[Kchnwtch]

Re: Help with thread callout - M22 x 1.0-6H 0.100R Thread

When you said "We've contacted several tech people related to the job." Does that mean you contacted the customer? Because, this is definitely a question you should be asking them."

Yes, we asked the customer's several tech people, none of whom drew the print, all of whom want the part, and none of whom really understand the process of threading.

When we asked them about it, they said we could just "go buy a certified gage and certify the thread." Which is not going to be easy to do if there's a radius affecting the go/nogo status of the thread. They want us to certify that it's right, even if they don't know what "right" means.

We are going to make sure it fits the mating part. But, we've been thrown to the inspection department before, after the fact, and faulted for not following threading procedures that were documented in obscurity, even though the parts fit fine. So we thought we'd ask around to see if we might be missing some documentation about thread standards.