What is the difference between these two subparagraphs?
If you have the 2018 std... compare 10.4.5.1 (a) and (c)
or
If you have the 2009 std... compare 7.4.5.1 (a) and (c)
There are obvious differences in wording, and one refers to a pic for a planar notch while the other refers to...
For the given parallelism tolerance, would you say that datum A constrains 2 D.O.F. or that it constrains 3 D.O.F.?
I can elaborate if you're curious why I pose this question.
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
Another thing I noticed in the 2018 standard is the graphic on page 264. On this forum we've discussed how having a profile tolerance reference a datum derived from the same surface might make some of the tolerance zone unusable (because the datum plane is created from high-point contact)...
In Y14.5-2018, I notice that Figure 12-16 shows references to datum B without the MMB modifier, despite the fact that datum B is derived from a pattern of two pins. Of course runout's datum references must be RMB, but in the past we've discussed on this forum how that isn't always very practical...
In paragraph 8.5 of the 2009 ASME standard (or 11.5 if you're looking at the 2018 standard), they mention in passing that "profile control is used primarily as a surface control."
The word "primarily" intrigues me, because what else could it be applied to? I'm thinking that that word should...
I suppose we could start an "errata" thread for the new standard, but here's one that I just noticed. In paragraph 8.4.3, it now says that the circularity callout "shall be specified on a surface and not to a size dimension." Yet in Figure 8-13 it has the FCF under the size dimension.
I...
I stumbled across a statement in Y14.5-2009 that doesn't sound quite right at first. Check out paragraph 5.4.1.2 on page 91, where it says: "Where the straightness tolerance is used in conjunction with an orientation tolerance or position tolerance value, the specified straightness tolerance...
I'm working with a drawing that follows ISO, and they have a profile tolerance with a circled Y after the tolerance number. Does anyone know what that means in ISO? It's not in any reference that I have access to right now.
There are actually two profiles: the upper tolerance frame has 1 mm...
Several things have popped up in various threads that always seem to leave this question lingering: When a profile tolerance is applied, is it required for the dimensions defining the shape to be basic?
We all agree that the dimensions defining the location of the feature do not have to be basic...
The ASME standard certainly allows double letters to be used as datum feature identifiers, once the single-alpha identifiers have been exhausted (ref. para. 3.3.2). But here's an interesting question:
Since the single-letter designation doesn't have to follow alphabetical order, would you say...
Something interesting that I just noticed, since I recently came across a real-world situation for it...
The Y14.5 standard goes into detail about how to use a position tolerance on a noncircular feature of size. See paragraph 7.4.5.
What's interesting is that all the verbiage is dealing with...
A technical spec has a flatness feature control frame with "TDL KK" The KK is a value in a table later in the spec (0.005" for my use) but the "TDL" is something I've never seen before. My first guess is that it means to look the KK value up in the table -- the acronym could stand for "Table...
For some reason my brain isn't firing on all cylinders this morning, so here's a quick Q ...
See the attached picture. Regarding the two profile tolerances: At first glance it might seem like the part is allowed to tilt into a parallelogram shape. But since the two profile tolerances have...
Please don't ask why I'm looking through the standard when it's nearly midnight, but... I'm hoping the other GD&T regulars on here can confirm a couple of minor things I've found in the 2009 standard. I'm not trying to nit-pick them (a job well done, I must say!), but here are three things that...
I suspect this topic has been covered here before, but I'll toss it out there again.
Does anyone have a problem with total runout applied to a tapered cylinder? I claim that it's OK, as long as the angle of taper relative to the datum axis is given as a basic dimension.
Some folks try to say...
I know this has been discussed several times as an offshoot of other threads, but I can't recall if it's had its own thread. The dilemma is whether a position tolerance can be applied to a traditional single hole through a plate, but the only datum referenced is the face of the plate. The...
I've been around CMMs quite a bit, but it was never involving runout. Can runout be checked on a CMM? We always talk about TIR/FIM and explain runout in terms of the dial indicator...blah blah... but I'm curious how it's actually done on a CMM if the part itself isn't set up to rotate...
Here's an off-the-wall question that came up this past week, and since Y14.5 doesn't directly address it, I'd like some opinions...
Suppose a zero/zero baseline is called out in each direction from a tooling hole, and positive and negative locations go out from that 0,0 position. If a designer...
Since we seem to be having so much fun on the other thread about TIR/runout, let me throw this one out there...
A major company that I work with is floating the idea of allowing GD&T specifications for runout (for now let's just say circular runout) but instead of mentioning a datum axis, as is...
I promise that I won't bring up the thing about directly opposed/calipers. [smile]
Last week I had a discussion with a colleague about some of the changes in the 2009 ASME standard. He pointed out something that changed, but I wonder if he's interpreting it as it was intended:
The new standard...
