# Thread: Slot with Basic location and size tolerance but no Positional

1. ## Slot with Basic location and size tolerance but no Positional

In the sample image is the slot fully constrained in both directions? We have multiple and differing opinions depending on whether we talk about the vertical or horizontal direction. (Datum A is not shown but is the large flat mutually perpendicular face). If it is what are the extremes of geometry that it allows?
Image corrupt

2. You need to reattach image - it was corrupt

3. Reposting the image. Hopefully not as corrupt.
gdt.png

4. 1) Circle P is Projection Tolerance Zone, there should be a Position or orientation geometric characteristic in the first horizontal frame. So, the specification is nonsensical as it is presented.

2) the 10 +/- 0.8 is a size control

3) the 30 +/- 2 is a size control

4) Assuming that the intended geometric tolerance is position (in place of the circle P), and the feature control frame associated with the oblong hole is attached to the 30 +/-2 size dimension the location of that feature is only controlled/specified left and right or horizontally. Measurements would made and the derived center plane from the radius's would need be as-manufactured within two tolerance planes separated 1.2 and oriented vertical and symmetrical about the 40.2 basic dimension.

See ASME Y14.5-2018, Figure 10-35 and associated paragraphs for an example and detail overview of the "Boundary concept".

5. The drawing is not the best but basically yes, it's fully defined. Well, I at least understand what they're getting at. The slots position can get larger in proportion to how much larger the slot size moves away from MMC. Also, if the overall length and width of the part gets smaller you can shift the part around within whatever the remaining tolerance allows to try and get the slots position to fall within tolerance.

6. Here is a resource to how to use GD&T to define a slot:

slots-precision-location-Article.pdf