Well, CheckerHater, as you said, and I agree, "Per-unit requirement works well with datumless controls" which is exactly what I show in the Tip. Since the unit basis control does not have a datum feature reference, it is free to float (in location and orientation) within the larger profile...
Easy now, CheckerHater. From the published Standard at the end of 8.3.2.2: NOTE: A profile per unit length, similar to that shown in Fig. 5-4 for the control of straightness, may be used to control abrupt transitions that occur when profile tolerances are specified on adjoining segments of a...
This is Don from Tec-Ease, Inc. Questions like this should be sent directly to Tec-Ease rather than to post here. And, yes, the answer is "most complex verification techniques"
To CheckerHater, the question did not say 'add", It said "modifying a tolerance" which we all know is the default...
The 0,0,0 is where the 3 datum planes of the datum reference frame intersect.
Is datum axis A the "axis derived from the datum feature simulator" as John-Paul said or is that the simulated datum axis? Some of these arguments, to the layman, are a distinction without a difference. In the 1966...
Using the right terminology will maybe help here. Datum feature A establishes the first plane of the datum reference frame. From there I can locate the hole relative to this first datum plane. I then use two points on the surface of the hole to establish the second datum plane. This plane...
SeasonLee, there is no problem dropping the datum feature B reference in the position tolerance on the pivot hole. Since it is the secondary datum feature, other features will be located from its axis. It is the origin for other features in the "vertical" direction. Also, not certain why you...
Hi fsincox, If you are referring to the perpendicularity comment, I have dealt with enough PPAP submissions where perpendicualrity was applied to a hole in sheet metal so no data could be gathered. At some point a little common sense has to kick in.
Back to the original question. Let's put a position tolerance of 0 at MMC on the two features serving as datum features A and B. Then it has the same meaning as CF.
As Evan said, in the first case with CF, one simulator would close in on the two features. The result could be that the part...
Here is a Tip I did on datum features "referencing themselves". Like Jim said, you have to distinguish between the datum feature on the part and the datum that is established by that datum feature.
http://www.tec-ease.com/gdt-tips-view.php?q=191
Before anyone responds with "how can this be...
pmarc is correct. The 3X should be removed from the middle drawing on the Tip. Cut and paste will get me every time.
This has been a great thread. Until the 2009 Standard there was no support for a pattern of features RFS/RMB. As Evan said, referencing a datum feature on an RMB basis is a...
The centers are merely to hold the part. They would be moveable (at least one is) to align the two features using an indicator. They are not establishing the axis. The same with the V-blocks. This is a very common practice on large shafts to establish a common axis between the journals...
Keep in mind that there is a difference between dimensioning (the goal) and tolerancing (how much you can blow it by). With dimensioning, a symmetrical relationship my be implied. But, features shown symmetrical must be controlled with geometric tolerances according to Y14.5. In other words...
I am a little confused by the question. You say there is no control frame but then you say there is a leader coming from the box. The box is the feature contol frame. Do you mean there isn't a datum reference? It is common, where two or more flat surfaces shown in-line on the drawing are to...
You will want to establish the datum axis using both diameters. You might be able to do this by using 2 V-blocks and aligning the two diameters with an indicator. Once they are aligned, you can check the total runout of each diameter. If the part has centers, you could do the same thing using...
