slot call out 2

[proEdj]

What is the best way to call out a slot? I have used basic dimension to reference the true center of the slot from 2 perpendicular datums. Then I called out the width of the slot and the height (the length from one tangent line off the full radius to the other tangent line) using standard dimension with tolerances. Then I called out the "2 X Full Radius" and also had a positioning block calling out diametric position of the center of the freature. Does this sound correct?

 

[ewh]

That is one of several correct methods.

 

[ctopher]

I had to read it a few times, sounds OK.
Just a side note ... "2 X" should be "2X". I see this a lot.

Chris, Sr. Mechanical Designer, CAD
SolidWorks 05 SP3.1 / PDMWorks 05
ctopher's home site (updated 06-21-05)
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[Hydroformer]

I like the automotive standard: Slot 8x14 (w/GD&T positioning)

regards,

Hydroformer

 

[TheTick]

"2 X Full Radius" on a slot callot is straight from the Department of Redundancy Department. Just say "slot".

 

[ewh]

I never thought it would happen, but I must disagree with TheTick. Y14.5 requires that "R" be called out, to ensure that it wasn't simply a mistake on the detailers part in missing a dimension. You don't need the "FULL" in front of it, but it does no harm in having that also. It really depends on what standard the drawing is done to (ASME Y14.5, industry or company).

 

[drawoh]

ewh,

I would say that the 2X R callout is correct, period, as noted in ASME Y14.5M-1994. I am not sure what it means when you add the word FULL.

All you are trying to say is that the ends of the slots are round, and their size controlled by the width of the slot.

JHG

 

[ewh]

drawoh,

I agree with you. I'm not sure where "FULL" originally came from, but I do remember having to use it years ago. It is not technically correct per ASME Y14.5-1994.

 

[ctopher]

I am not sure where it originated. I have been told by machinist's and inspectors that if you call out "2X R" on a slot, it can be technically any radius. If you call out "2X R FULL", it is a radius exactly the width of the slot (same tolerance).

Chris, Sr. Mechanical Designer, CAD
SolidWorks 05 SP3.1 / PDMWorks 05
ctopher's home site (updated 06-21-05)
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FAQ559-716
FAQ1010-1130

 

[ajack1]

I would agree with hydroformer, but maybe that is because I also am familiar with automotive standards. Failing that the slot size and two full radii, if you specify the length and width of the slot and the radii and start using limits you can end up with a flat or “short” radii on the ends, is that what you want?

I do however have no idea about American standards.

 

[ewh]

According to Y14.5, hydroformer's method is close to being correct. The standard omits the word "SLOT" from the callout, and states that the end radii are to be indicated but not dimensioned.

 

[TheTick]

No arguing with the standards. Seemed too obvious on the surface. Star for ewh for actually looking this up.

 

[Tunalover]

ProEdj-
Don't you have a copy of Y14.5M-1004?


Tunalover

 

[drawoh]

Tunalover,

Don't you mean Y14.5M-2004? I just looked at

http://www.asme.org.

The standard is still 1994, re-approved (re-affirmed?) 1999, unless their website is out of date.

JHG

 

[Hydroformer]

Dang, just pulled a drawing to check... The word "slot" isn't there. Just the length x width (and tolerances) above a feature control frame to define positional tolerancing.

Keeping in mind that these drawings are 'pictorial representations' and CAD is the MASTER.

regards,

Hydroformer

 

[Tunalover]

Sorry-
I meant Y14.5M-1994.


Tunalover

 

[drawoh]

ewh,

I don't know where FULL comes from either, although I have seen it used.

I just pulled out my Engineering Drawing Sixth Edition, by Thomas E. French (1941). They draw the slot and show the ends round. There is no radius specified, and no mention of FULL anything. They dimension either to the centre or to the ends of the radii. Tney do not show tolerances, even on the drawing that shows limit dimensioning all over the place.

JHG

 

[Tunalover]

Folks-
Why use drafting references from 1941? If you use Y14.5M-1994 and Y14.100M (and the standards referenced within) and can't go wrong! There's too much to worry about at work besides drafting and tolerancing practices. Why not go with the standards?

I work at a company where each designer and engineer does his own thing; beyond the format, a drawing from one guy looks completely different from a drawing from another guy. As for me, I prefer to "go by the book" rather than rely on something that I may have seen or did ten years ago.





Tunalover

 

[Heckler]

IAW ASME Y14.5M - 1994 a slot can be dimensioned as such listed on page 15 figure 1-35. The end radii are indicated but not dimensioned. Also, refer to page 143 figure 5-47 for another example of a typical slot.

 

[drawoh]

tunalover,

I do not use a drafting reference from 1941, at least, not for drafting. I collect old books, and I am curious about old engineering texts. The 1941 text sits on my bookshelf next to a couple of books from 1835 and 1844, which do not describe how to dimension slots (drat!).

We seemed to be discussing old drafting procedures. I was not advocating the 1941 procedure. I was describing it. Somebody swiped my old drafting textbook which was based on ANSI Y14.5M-1976(?). That might have been more interesting.

I prefer to use ASME Y14.5M-1994 for drafting. I only wish more people understood it.

JHG