×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Shaft and Hole designations used in American-British-Canadian System (ABC)
2

Shaft and Hole designations used in American-British-Canadian System (ABC)

Shaft and Hole designations used in American-British-Canadian System (ABC)

(OP)
Hi,

I was wondering if somebody could explain the meanings of the symbols used in the shaft and hole designations of American-British-Canadian System (ABC)?

So far all I have turned up are cut & paste paragraphs from Machinery's Handbook which mentions the symbols eg H7, p6 etc but nowhere can I find a description of what 'H' or 'p' etc actually mean.

Thanks

Nic

RE: Shaft and Hole designations used in American-British-Canadian System (ABC)

DrBwts,

Do you have a whole Machinery's Handbook? It is the bible around here. I am less interested in the tolerance classes, and very much more interested in the fit classes, explained in some detail. The tolerance classes are used to achieve these.

I keep a handout in my Machinery's Handbook that I was probably given in college, that explains the fits in somewhat more detail. I do not know where it came from.

The tolerance classes actually are an ISO standard, also explained in the Machinery's Handbook.

--
JHG

RE: Shaft and Hole designations used in American-British-Canadian System (ABC)

(OP)
Thanks KENAT I'm looking for something that explains what the actual designations 'H' or 'p' or 'g' mean.

I get that H7/h6 is a nice snug clearance fit or that H11/c11 is a loose running fit but what does having a 'H' or a 'c' mean?

RE: Shaft and Hole designations used in American-British-Canadian System (ABC)

(OP)
Hey drawoh

Yes I have copy, I was looking up some stardard tolerances when the thought occured 'is there some logic to the letters & numbers used?'

RE: Shaft and Hole designations used in American-British-Canadian System (ABC)

Capitals "H" are used for holes. lower case "h" are used for shafts - in other words male parts. There is the concept of "unit shaft" - not frequently used - were you pair the h-tolerance field with every thing else and also "unit bore" were the "H" gets paired. The "H" and/or "h" is something like State street in Chicago, the dividing line - to the right you have letters "i" through "z" were every thing gets tighter as you go and to the left you have letters "g" through "a" were it is the other way around - it gets looser.

RE: Shaft and Hole designations used in American-British-Canadian System (ABC)

(OP)
Thanks Occupant, what about the numbers eg H7/h6?

RE: Shaft and Hole designations used in American-British-Canadian System (ABC)

H(bore)/h(shaft) is known as a locational fit - where parts are closely mated without interference so that they can be easily assembled and disassembled. The numbers indicate the tolerance field, the larger numbers a generally chosen for the bores because those tolerances are more difficult to achieve in machining. E.g. H7 (and also h6) can generally be obtained by grinding, hard turning, broaching etc.

RE: Shaft and Hole designations used in American-British-Canadian System (ABC)

you can thank our european cousins for this , years ago I remember you had press fits, interference, running and sliding fits.. things used to be easier :P

RE: Shaft and Hole designations used in American-British-Canadian System (ABC)

You need to get DIN/ISO 286 part 1 and part 2.
ISBN 3-410-12677-5
A small pocketbook from:
All Dim's are metric.
Learn how the system works.
Just getting the numbers for a certain combination will help you one time only.
But you really need to understand the system.
Good explanation here: http://www.gbi.bgk.uni-obuda.hu/oktatas/segedanyag...
Here is a start: http://mdmetric.com/Ch6.8wGO.pdf
You can call or fax Beuth and ask for the pocket book in English on DIN/ISO 286
ISBN 3-410-12677-5
Approx. $20.00

Call or fax: Phone: +49 30 2601 2759
Fax: +49 30 2601 1263

From the US use 011 to get out, than 49 to get into Germany

RE: Shaft and Hole designations used in American-British-Canadian System (ABC)

(OP)
Thanks juergenwt that was exactly what I was looking for.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources