Rule #1 and form thread
Rule #1 and form thread
(OP)
Is rule#1 applicable to the form thread?
I have a situation where an internal thread must be verified with a Go gage (plug gage). The question is: does the go gage --plug gage-- need to be (must be) as long as the female thread that is checking or can be shorter? If the go gage-the plug--is shorter do we run the risk that the female thread (internal thread) being bend and the plug won't catch that form error?
Any clarification on my dilemma will be greatly appreciated.
(manufacturing is using a go gage with only 3-4 spirals to check the size of the female thread which is 8-9 spirals long).
Any standard (ASME, AISI, etc.) I can use to get more info?
I have a situation where an internal thread must be verified with a Go gage (plug gage). The question is: does the go gage --plug gage-- need to be (must be) as long as the female thread that is checking or can be shorter? If the go gage-the plug--is shorter do we run the risk that the female thread (internal thread) being bend and the plug won't catch that form error?
Any clarification on my dilemma will be greatly appreciated.
(manufacturing is using a go gage with only 3-4 spirals to check the size of the female thread which is 8-9 spirals long).
Any standard (ASME, AISI, etc.) I can use to get more info?





RE: Rule #1 and form thread
RE: Rule #1 and form thread
Unless you're using a weird, customized thread size, wouldn't the form error be covered in the thread specs given by Machinery's Handbook or similar guide? (I don't have MH here at home so I'm just tossing it out there.)
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: Rule #1 and form thread
And another question is: if the minor diameter is verified (with a GO gage pin) is it acceptable that the GO gage pin length’s to be only the thread pitch size?
½-20 UNF (pitch size .05). Minor diameter is to be verified with a Go gage pin. The length of the pin that must pass thru the thread could be only .050? Or must be at least as long as the thread is?
RE: Rule #1 and form thread
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
RE: Rule #1 and form thread
You may want to look into something like ASME B1.3 for more information.
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: Rule #1 and form thread
4.10.8 Runout.
The pitch and major cylinders of the threaded portion of the GO segments or rolls shall not exceed the runout as determined by measurements of runout (full-indicator movement) on each gaging member, with respect to pitch cylinder. Runout shall not exceed one-half X gage major diameter tolerance.
Isn't it more stringent than rule#1?
RE: Rule #1 and form thread
Individual standards say something like this:
"5.6 Length of Thread Engagement
5.6.1 Normal Length of Thread Engagement. The pitch diameter tolerances specified herein are applicable to the limits of the normal length of thread engagement LE in Table 7. The limits were calculated by formulas given in para. 6.4."
So, normally your thread GO gauge has to correspond to "normal engagement length" specified in standard for your particular kind of thread. NO GO gage may be shorter, just like on this picture: http://files.engineering.com/getfile.aspx?folder=9...
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: Rule #1 and form thread
Where is your statement from? (5.6 length......) I cannot find it in B1.3.
Is it from ASME B1.1 (Unified Inch Screw Threads)? Or from ASME B1.2 (Gages and Gaging for Unified Inch Screw Threads)
or from other standards?
Please kindly let me know.
RE: Rule #1 and form thread
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: Rule #1 and form thread
5/8-14 ACME-4G
ASME/AISI-B 1.5
RE: Rule #1 and form thread
(For whatever it's worth)
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: Rule #1 and form thread
RE: Rule #1 and form thread
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: Rule #1 and form thread
However, it was my understanding that even most standard thread classes have an 'upper limit' of engagement length where you need to start worrying (e.g. >2 major diameters as you mentioned) and there might be a (possibly poor) reason someone chooses to exceed that. That's more of what I was referring to. I'm not sure if that's necessarily the case here.
RE: Rule #1 and form thread
OP was asking if the length of gauge is defined somewhere, so there it was.
I agree that there might be reason(s) for using special threads, that's why they call them "special"