Kego,
I don't know what type of joint you are designing but there are many designs that incorporate two round dowels and two round dowel holes. Almost every coupling where axes on either side of a housing joint must align (where alignment is not provided by the components alone) use two round...
I have no knowledge of the recent exchange so I'll enter the water calmly.
Roundness is form only so the axis it is compared to is its own... I choose a) 0.05
I would re-word the comment "As we all know, Runout indirectly controls Roundness." Since a perfect roundness can have a imperfect...
If [A], [B], & [C] Orient, Locate, and Stop rotation of the part respectively in their assembled condition ... and the material edge location is dependent upon the DRF [A|B|C] then it is fitting that the origin is at the intersection [A] and [B] and oriented for rotation to [C]. The DRF does not...
Any discussion of how it should be tolerance should beg the question "how does it function... what orients and/or locates what... what tolerance liberties and refinements are necessary for ideal function?"
If the flatness and perpendicularity were extracted leaving just the profile all over...
should be... examine what wins in constraining the three rotation and three translational Degrees-Of-Freedom for the part you are detailing in the assembly or function.
pmarc,
Clamp load(maybe 800+ Kg)assisted by shank clearance maybe 3/4 MM all around... Just guessing... In ronj100's clevis the translation along the axis may actually be a width with clearance or it may have some sort of gravity assisted ramp for self closing... I don't Know!!! That clevis...
pmark,
You are correct he didn't specify... I said "may have" not "are"(were) and I will stick with my functional assessment. I believe as I have said before get the datums right first and the rest will fall in place.
ronj100
See slide 3 for a possible solution.
I believe you may have your datum features mixed up for their functional influence on the assembly. Functionally I don't think that the shoulder surface can arrest the two rotational degrees-of-freedom away from the long perpendicular cylinder...
jimbod20,
you said:
WHY MMC! Is there any functional purpose to permit the ten tolerance zones (projecting radially, equally spaced, and perpendicular to the primary datum feature's axis) to translate at minimum or translate and rotate away from that axis variably according to their size? I...
Supergee,
Think of an engine head gasket... the cooling and lubrication holes in the block and head that pass fluids through the gasket as well as those gasket holes should have their tightest constraint functionally at LMC... while the head bolt holes and perhaps the dowel pattern spread...
Well done Evan... your attention to detail is showing!
Now if we only had the feature sizes we would re-optimize and predict the precise amount of slop that the attribute gage could split in any given vector...
SeasonLee,
Attached is 1) your pattern un-fitted (referenced from the center of the pattern)and 2) your pattern hand fitted (by eye) by rotating and translating the basic pattern and its known individual tolerance zones over a map of your measurements. Of course all of the tolerance zones are...
PMARC,
It is the difference between the individual feature’s MMC size and its pattern constrained oriented actual mating size as the collective pattern is simultaneously expanded/contracted among the pattern features until expansion is limited by at least one feature, then sequentially...
