Burunduk,
This is how I understand the OP's description. In particular this:
"I then need the Y direction spacing to be at the .750 basic hole to hole position with a tolerance of .014 diameter for the cylindrical zones, but only in the Y direction".
Whether this is valid functional need or...
I would propose the following solution:
1. Show XYZ coordinate system in at least two views of the drawing.
2. Control each pair of holes with two separate callouts:
2a. First callout - single segment position tolerance of dia. .125 relative to |A|B|C|.
2b. Second callout - single...
bc23,
Note that my suggestion was more about addressing the datum target setup itself based on the information provided in the initial post. Keeping perpendicularity tolerance for the hole does not guarantee its location close (that is, within a tolerance) to the tangency point. To guarantee...
Define the plane tangent to the arc at its quadrant as datum target plane A1.
Next, define datum targets B and C on some other features of the part to fully and repeatably immobilize the part for the check of the perpedicularity tolerance.
Then, specify the following, or similar, note (taken...
ALL OVER could probably work as well.
In my mind, SIMULTANEOUSLY sounds more straightforward and provides more flexibility, but I understand others may see it differently.
Frokilin,
I don't think this would solve the problem I described and you quoted.
Imagine that the general note is like this:
UNLESS OTHERWISE SPECIFIED, |PROF|.04|.
(Notice that, according to the problem statement, I did not specify any datums in the profile FCF.)
So it is rather clear that...
Yes, the lack of training, or incorrect training, is a problem. I just think that this small change in the standard - the addition of two distinct modifiers for MMB and LMB - could significanly improve the learning process.
Burunduk,
I see, but :-) if they both invoke virtual conditions, then why do they need to be called differently? (Don't get me wrong, I believe they should be called differently). Shouldn't their location in the FCF be then sufficient indicatiton that one applies to the controlled feature's VC...
My opinion...
The mistake the Y14.5 committee made when the MMB and LMB terms were introduced in the 2009 version of the standard is that they did not introduce two new modifiers for these terms, but decided to use the MMC and LMC modifiers instead.
Generally, people have a good grasp of how...
SeasonLee,
Yes.
Of course, depending on the function, you may still add MMB modifiers after both datum feature letters in the position FCF for the large cylinder.
The other option suggested by Burunduk may work as well, but only if the datum cylinders can be defined with the same size callout.
SeasonLee,
If you don't like the A(M)-B(M) option in the position FCFs for datum features A and B, you can specify position FCFs without datums and with SIM REQT note associated with them.
But, as was already said, you need to have a position tolerance (or other tolerance that will is able to...
The proposal provided by 3DDave will work, but both single-segment FCFs of 0.4 will need to be associated with a SEP REQT note. Otherwise, the spacing between them, due to the default simultaneous requirements rule, will still be controlled within 0.4.
Of course, the datum feature C symbol...
They do not allow for MMB/MMR on planar datum features even if the feature has location relationship to the higher order precedence datum.
I would say it's one of few areas where ASME has more tools in the toolset than ISO.
greenimi,
It wouldn't be legal in my example, where A and B are surfaces. But if B was a feature of size, then (M) modifier after B would technically be legal in the lower segment in ISO.
BS standards generally follow ISO. In ISO, there is no composite tolerancing, however there is a way to define equivalent requirements with the use of two single segment position tolerances.
Assuming A is a flat bottom surface of a block and B is one of its sides, the corresponding callouts in...
My additional question was not about the manufacturing precision and the accuracy of gage components used in the proposed setup. Notice that in my example I made the flat surface perfect, yet the dial indicator reading could get quite significant due to a non-optimal installation of the part...
All I wanted to accomplish with my question was to hear that an optimization would be needed as an additional step in the inspection process to ensure satisfactory level of confidence of readings.
Burunduk, I was not thinking about the accuracy of the gage components, but rather about something as shown in the picture below (it illustrates an exagerrated situation of the part rotated 180 degrees about datum "axis" A).
Does this make sense?
Got it.
One more question: Assuming the flat surface was manufactured exactly at the true profile (for this condition we know the measurement reading should be zero), how does this setup ensure that the flat surface is parallel to the surface plate?
