Dimensioning of Slots (SW 2009 and ASME Y14.5M)

Ever since the addition of the slot tool, SolidWorks almost seems like a whole new software for the those who design machined parts.   Adding the functionality was one over due accomplishment.   Another accomplishment was making sure SolidWorks supports standard methods for dimensioning slots.

ASME Y14.5M-1994 paragraph 1.8.10 and figure 1-35 provide three methods for the dimensioning of slots, with no stipulation regarding which is preferred for particular scenarios.   (Note: all three methods require the insertion of a non-dimensioned “2X R” note pointing at one of the slot’s end radii.)

In one fashion or another, SolidWorks 2009 supports all three methods, though it does have a default for both simple slots and arc slots.  For brevity, this article will only cover simple slots.

The first method (a) provides the width and the distance between the end radii center points.

Method (a)

Method (a)

The second method (b) is the easiest and simplest to dimension.  Simply state width and overall length, and use an arrow to point to the slot’s object line.  Though originally reserved for punching operations, ASME Y14.5M-1994 allows for the use of this method on any simple slot.  When using hole wizard to dimension a slot in SolidWorks 2009 or higher, this is the type of dimension that is inserted.  (A future article will address how to simulate this method in SolidWorks 2008 or previous.)

Method (b)

The third method (c)  provides the width and overall length of the slot in linear dimensions.  This method is preferred if the slot has positional tolerances that use the boundary method (see ASME Y14.5M-1994 figure 5-47).

Method (c)

Method (c)

Side note: of the three choices, the ASME board almost left out (a) and (b).  The original release draft of ASME Y14.5M-(1994) only shows method (c) in figure 1-35.




Author: fcsuper

As a drafter, mechanical designer and CAD engineer, I've been in the mechanical design field since 1991. For the first 8 years of my career, I was an AutoCAD professional. I utilized AutoLISP and many other AutoCAD customization features to streamline drafting activities for 6+ drafters and designers. I authored several custom functions, one of which was published in the March 1997 issue of Cadalyst Magazine. Since 1998, I've been used SolidWorks non-stop. I've worked to utilize the SolidWorks' user environment to simplify drafting and design activities for 20+ engineers. I've created this website to provide current information about SolidWorks from a variety of contributors. More recently, I am now employed by Dassault Systemes as SOLIDWORKS Sr. Product Definition Manager to improve drawing, annotation and MBD related areas.

10 thoughts on “Dimensioning of Slots (SW 2009 and ASME Y14.5M)”

  1. Where do I find out how create the right kind of slot that holewizard will operate on, as you suggest here.

  2. Dave,

    In SW 2009, you simply use the slot sketch tool and extrude cut. On the drawing, click on hole callout button and then click on one of the radii of the slot.

  3. None of the examples in Fig 1-35 of the ASME Y14.5-1994 standard the similar figure in the 2009 standard uses a linear +/- dimension to “locate or orient” the slot as shown above. The figure only shows examples of how to dimension the slot itself. See figure 5-41, although showing a hole, for one example of how one might locate and orient a slot using a rectangular tolerance zone. See figure 5-47 to see another example using position boundary for location and orientation. See figure 6-19 for yet what I personally think is the best method to dimension an “irregular” feature of size when the entire boundary of the surface is functional.

  4. Norm, although I don’t disagree with you, the reality is that many in the engineering field have an irrational fear of GD&T callout that you are suggesting. The location and orientation shown in my examples above is meant to be illustrative and does not necesarily preclude the use of basic dimensions.

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  6. In the Method (b) Can I call out the “2X R” with the same leader as the slot???? and the depth??????
    thank you
    Cody

  7. i need help for straight slot how to black it .i mean fix it .if three straight slot are given how we give them relation between them

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