Dimensioning bores 2

[Grindy]

I'm currently designing a parts catcher for a machine. Doing detailed design work is something relatively new to me so I'm unsure about drawing standards and dimensioning.

I have a shaft that is 45mm in diameter. A 'sleeve' will slide over the shaft. I require a clearance fit (H11). According to my Zues book a H11 fit for a hole in the region of 45mm dia would result in a bore size of 45.160mm.

My question is this:

In the drawing do I label the bore to be machined to 45mm with a H11 fit or do I label the bore to be machined to 45.160mm.

Also, could anyone recomomend a good drawing standards and geometric tolerancing book (SI)?

How do I then go about giving the machinists a tolerance?

Would the 45.160mm be my maximum bore size or would I have a tolerance +/- either side of 45.160?

 

[juergenwt]

fsincox - I can not answer your question on "position on surfaces". We manufacture mostly small precision parts ( Industrial Sewing Machines) and on our prints we will have a note: "Unless otherwise specified all tolerances are ISO 2786 -m" or f, c, v.
Tolerances under ISO 286 are given as for instance 12H7 or 12h6. Of the two systems "Standard Shaft and Standard Bore" most will use "Standard Bore (Hole)" since this system will save you money on gaging equipment and it is easier to produce a shaft at a tolerance required for a specific fit.
Reamers for instance are marked H7 and that is all you need in most cases and coming from a tool room background - one set of H7 reamers (2H7, 3H7, 4H7 etc.)is all that you will need. Reamers are not marked 12 +18. If you mark your print with the tolerance listed i.e. 12 + 18 the shop may not know that this is a standard 12H7 reamer tol..
Also by listing a tol. as for instance 12H7 for the hole and 12r6 for the shaft the shop can look at a DIN 7157 (sorry I don't know the ISO #)table and they will know what type of fit is required. In this case a light press fit.
In a separate block on the bottom of a print we list all ISO 286 tolerances on this print with the +/- call out.

 

[fsincox]

They do not specify the sizes in your shop either? I assume you interpret these drawings then, and have no issues? I would like to experience an environment like that, just to see how it works. Guys, can we take this to the ISO section? Envelope or no envelope?

 

[fsincox]

Do you want and ISO based book or ANSI book on GD&T? there is ANSI in metric here.

 

[fsincox]

Is Zeus not a good reference for GD&T? Is it just the fit tables?

 

[fsincox]

KENAT
used it in anger? I didn't catch that at first, what do you mean by that?

 

[fsincox]

juergenwt,
I mean does the ISO still allow the use of position tolerances on surface locations shown with basic dimensions?

 

[pmarc]

fsincox,
Yes, ISO still allows the use of position tolerance on surface locations with basic dimensions. The meaning of this concept is the same as profile of surface tolerance in Y14.5.

 

[fsincox]

Thanks, pmarc. Are you ISO too? I knew ISO had profile, now, so I wondered if they still allowed position usage on surfaces. I really never understood why it need to be different, conceptually. My guess is politics. One thing that pops up in debates here is this whole feature of size vs feature issue, which seems to complicate it for us, if we had just stuck to looking at features it wouldn't make any difference, would it?

 

[pmarc]

fsincox,
I work for company that follows ISO 1101 standard regarding GD&T and I am not so happy with it as I think Y14.5 is much better, precise and logical (even despite few unclear issues like feature of size definition).

If I understood you well, you would like to consider all features of size simply as features?

 

[fsincox]

pmarc,
I am not sure, I am really trying to understand why ISO doesn't have the issues using position on surfaces and we did. I do think the feature of size issue for us has created a problem that I feel was not necessary. In the 2009 standard now we broadened features of size probably because we limited it’s definition in 94.
Shall I assume an American based foreign company then?

 

[KENAT]

fsincox, you're taking this way off topic from Grindy's OP. If you want folks to join one of your discussion threads on ISO/GD&T etc. then I suggest you put the link to that thread rather than just vaguely asking them to join the discussion such as thread182-247563 or which ever one it was.

Also, I re-read this my posts and didn't see where I said anything about "used in anger", I suggest you give date & time reference in future.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[looslib]

Kenat, This is the post where you said it. 18 Dec 09 10:15

"Zues is typically a pocket guide for machinists. I have one here on my shelf though I haven't

used it in anger

since I came to the States."





"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli

 

[KENAT]

Oh, now I see it, thanks. Yeah, it mostly being metric based I haven't used it much in the US. Plus for some of the stuff that is in there I have internet bookmarks or stuff posted on my cube walls.

I also got burnt early on trying to use some of my old references even for US metric stuff since there are some differences. For instance head height on metric panheads found in North America is typically taller than in most other parts of the world.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[fsincox]

kenat,
The "in anger" part was the part that thru me.
Obviously, you can see I am trying to move my stuff else ware.
I do not know how to paste threads like you do

 

[KENAT]

Just cut and paste the line under the title of the thread you want to link. Essentially "threadxxxx-yyyyyy"

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[vc66]

Zues is typically a pocket guide for machinists. I have one here on my shelf though I haven't used it in anger since I came to the States.

V

 

[KENAT]

? looslib had already pointed out my myopic tendencies, but thanks for really rubbing it in!;-)

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​