Thread specification on German drawing
Thread specification on German drawing
(OP)
I've got a German drawing produced in the early '80s that specifies a few threaded holes as: M24 "b". Does the "b" indicate pitch? And if so, what pitch?
Thanks in advance,
minerk
Thanks in advance,
minerk





RE: Thread specification on German drawing
RE: Thread specification on German drawing
M24x2-4g6g EXT
M24x3-6H INT
According to the MH it's a simplified international practice for designating coarse pitch M profile metric screw threads is to leave off the pitch. Thus a M24x2 thread is designated just as M24.
Heckler![[americanflag] americanflag](https://www.tipmaster.com/images/americanflag.gif)
Sr. Mechanical Engineer
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RE: Thread specification on German drawing
RE: Thread specification on German drawing
US is the only place I know of where you don't just leave off the pitch to specify standard course pitch.
KENAT, probably the least qualified checker you'll ever meet...
RE: Thread specification on German drawing
RE: Thread specification on German drawing
Unless you were making the point it should be A & B.
I thought b may be something to do with DIN ISO 2768-1 but they only appear to use f, m, c, v, H, K & L and I'm not sure it would apply to a thread anyway.
"US is the only place I know of where you don't just leave off the pitch to specify standard course pitch. " - this only applies to metric threads, should have been clearer.
KENAT, probably the least qualified checker you'll ever meet...
RE: Thread specification on German drawing
external = e, f, g, or h
internal = G or H
M6-6h is male
M6-6H is female
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RE: Thread specification on German drawing
In your first post, "Not sure what the b would mean"
So obviously you were not familiar with the a/b = male/female thread designator either.
In your second post, "CBL, you've obviously never specified UN series threads, or at least specified them correctly to ASME B1.1
Does ASME use the a/b designation for male/female threads? If so please post an image of how it should be shown.
Also in the second post, "I thought b may be something to do with DIN ISO 2768-1 but they only appear to use f, m, c, v, H, K & L and I'm not sure it would apply to a thread anyway"
Back to first post.
RE: Thread specification on German drawing
it is quite common to specify external
threads by adding 1A or 2A or 3a
and internal threads by adding
1B or 2B or 3B for the inch series.
For example 3/4-10UNC-2B
This indicates the tolerance field by the
external or internal thread.
For metric threads i.e.
M24-4g6g lower case indicates external
no pitch designated coarse thread
M24x3-6H upper case indicates internal
I have never seen "b" as a designation for
a tolerance field but if it is specified
to a particular din standard it may indicate
per that din standard an "a" "b"
designation as in tapered, straight
for a grease type thread din standard.
Or is it simply defining a footnote on
the drawing?
RE: Thread specification on German drawing
RE: Thread specification on German drawing
KENAT, probably the least qualified checker you'll ever meet...
RE: Thread specification on German drawing
RE: Thread specification on German drawing
A=external or pin, B=internal or box threads, in the imperial system either class 1, 2, or 3. I use this convention all over my prints for the past forty (40) years.
His example "3/4 - 10 UNC-2B" is bang on!
Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada
RE: Thread specification on German drawing
After reading Heckler's response I found the page in MH that he refers to, and am treating the thread as coarse pitch.
Thanks for all the input!
RE: Thread specification on German drawing
cockroach is correct, the 2B refers to the tolerance class and the B indicates internal threads. The B is a not there to specify the thread, but as a modifier of the tolerance class. Internal and external tolerances are different for the same class, so it is a part of the tolerance callout.
Timelord
RE: Thread specification on German drawing
RE: Thread specification on German drawing
But good luck with it none-the-less.
Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada
RE: Thread specification on German drawing
"We don't have an ensured explanation for the "b".
M24 is for sure a metric thread
We have used in the '80s such a "b" as an exchange index on drawings. Example: if the tread was before M20 and we changed it to M24, the whole drawing remains with the same number, but Index "b"."
Check the revisions block. I can't do any better than that.
RE: Thread specification on German drawing
KENAT, probably the least qualified checker you'll ever meet...
RE: Thread specification on German drawing
RE: Thread specification on German drawing
Ah so, it is a revision "b".
Do you have a good German Dictionary?
I have translated more than a thousand drawings from
Germany and in the revisions they often use abbreviations which compounds trying to use a direct translation.
Good luck.
RE: Thread specification on German drawing
the abbreviation in the revision indicator box means "Positionsbezeichnung in Übersichtszeichnung hinzugefügt" which means something like item indication added in overview drawing.
Kind Regards,
hahor
RE: Thread specification on German drawing
RE: Thread specification on German drawing
It's tough to find translation for technical terms to begin with, but throw in a few abbreviations and it's nigh impossible. You would think that the folks here who bought this equipment would have had the sense to have the drawings translated as part of the deal!