Ahh I see... I wonder if something like this would work. Chain lines are typically used to indicate that something applies to a partial surface.
https://files.engineering.com/getfile.aspx?folder=2ed5c4e3-903a-4c96-b5ab-fc74304ff67d&file=perp_sep_reqts.PNG
It sounds like you have two separate requirements for perpendicularity.
Can't you just call out both?
Assuming that the elements 1, 2, 3,...n are 1-inch, maybe the picture below will do the trick?
I cannot think of any reason to use an LMB modifier on a datum in the real world.
I think that I burned out a few brain cells trying to understand pmarc's comment that the LMB is less than the minimum diameter.
It makes sense, but sheesh! I would have missed that in a tolerance stackup for sure.
Which brings up an interesting question: "Does a key count as a fastener?"
Apparently ASME is considering a dowel pin to be a fastener, per the ASME Y14.5-2018 quotation.
A key is similar to a dowel pin in function.
One example might be a rectangular key which is installed into the slot. This would be similar to a dowel pin installed into a hole.
The projected tolerance will ensure that the key (or pin) can assemble into its mating part, including any perpendicularity error.
Per the title: Is it legitimate to use a projected tolerance zone for the position of a slot, as you would with a hole.
I think that it is legitimate based on my understanding of projected tolerance, but I've never come across it in the wild.
ASME Y14.5-2009 Para 7.4.1 recommends use of...
Although there are implied basic dimensions for orthogonality, co-axiality, co-planarity, etc., there is no default geometric tolerance on that co-axiality.
But, you can certainly use a general note to apply a global control of position tolerance on your drawing.
For example:
UNLESS OTHERWISE...
Imagine that this was hand drawn blueprint.
If you change a basic dimension on the bottom, what are the chances that you'll forget to change the top dimension?
(e.g. what if the 4mm slot became a 5mm slot...)
There should be a single definition for the basic shape of the part.
This prevents...
I think you can use a datum target to establish the tertiary datum.
However, datum C doesn't look very functional to me as you've shown it.
Have you considered using the bolt holes as datum B and locating all of the features on the part relative to the hole pattern...
Is there a material condition modifier? That position tolerance without any bonus would be extremely difficult to achieve.
That said, it's not uncommon to have zero positional tolerance at the maximum material condition, where the position error tolerance is only related to the size of the...
Sorry, I should have been more clear. They currently use a fixed gage to derive the center. I was saying that the method you suggested would require a expanding mandrel, so it'd be a bit different.
Oh geez... managing data is really hard to do well.
I think the only sane way to manage large amounts of technical data is with some kind of a database.
For engineering, a PLM system like TeamCenter is quite common, and a good way of maintaining associations, revision control, etc.
I have...
If you're just trying to break sharp edges on a machined part, go with a small chamfer. It will be less expensive and to produce and inspect.
If the part is to be shot-peened, you probably want to have an edge break of .030" or bigger to avoid edge roll-over.
If it's a cast part, a radius will...
I agree with this interpretation, but this is slightly different than the inspection that they're doing today: expand a centralizing mandrel inside the slot until it touches the angled faces, 10 mm from surface A and find the centerline.
Actually, I prefer to use profile tolerance, as suggested...
I think that I'm not being clear. I think that the recommendation in Burunduk's link is pretty much what I'm after.
However, I was thinking that a tapered slot is not a feature of size, and position tolerance must be applied to a feature of size per Y14.5. In the link, they claim that the slot...
...except position tolerance is applied to a centerplane.
The problem is that it is typically applied to the centerplane of a feature of size.
Hence, I think a note might be appropriate, since a tapered slot is not a feature of size...
I'm not saying he's wasn't that. But the quote is good.
We make individual choices. If you're missing your kid's soccer games for work, or if you're never putting in any extra effort into your career... there are consequences. We need to prioritize things that are important to both our family...
