Hi..Nice Explanation! Thank you so much! I have a doubt,Please help me.. Why orientation is not controlling location..In your example if only parallelism is given with nominal dimension..What would be the result.Please help me to understand..Thanks Again!
Parallelism only controls the orientation of the feature relative to the datum reference frame. It does not control the location of the hole. A position tolerance, however, must be centered on the true position (basic, theoretically exact dimensions)
No difference on this example because there is only a single feature. The lower frame of a composite constrains rotational degrees of freedom only. This would control orientation only to the lower datums just like the parallelism. However, composite position would be different if there were multiple holes. The lower frame of composite would also control location between the features in addition to orientation to the datums.
For clearance holes: position tolerance can be calculated by the fixed or floating fastener formula (MMC hole-MMC pin). For an example like in this video: The calculation is "how much can you allow the hole to be misaligned". You need to zoom out and look at the overall assembly and decide how precise it needs to be to function.
It reminds me of a composite callout which I came across a few days ago, the drawing is provided by our customer tesla which means they are ASMY based.There are two rows in total, the first row is the profile 0.1 respect to datum A,B&C while the second row is only flatnes which is also required 0.1. Is it a correct call out for the second row, I don't think it does make sense .
For a drawing to ASME, any datum feature references in the lower tiers of a composite frame constrain in rotation only. It sounds like your frame does not have a datum feature references in the lower frame (so it does not matter if it is composite or not). The lower tier profile controls only size and form of the surface.
@@GeoTolPro Yes,the lower tier doesn't have a datum feature references,but shouldn't the lower tolerance be tighter than the top tier of a profile tolerance. In my case, both of them have the same tolerance which is 0.1.
Great explanation! Would you mind explaining how to determine the position or perpendicular tolerance if a pin like a dowel pin and a hole use a interference fit? like Ø5 H7/p6, press fit. Would you use MMC with 0 tolerance for the tight tolerance like this? I'm not sure how to do this correctly? I've been haunted by this kind of problem for a while. Thanks!
The position or perpendicularity tolerance has no effect on the press fit. Size tolerance alone insures they press together. Position controls the relationship to other features on the part.
Yes, the lower segment of a composite tolerance controls orientation only to the datum reference frame. In this example it would be the same. However, I like parallelism on this simplistic one-feature example. I use composite position where it's pattern of features that also needs grouping.
Finally this is how the black magic is made... thanks for you videos . where's I have now understood what GD&T is in simple ways..
Hi..Nice Explanation! Thank you so much!
I have a doubt,Please help me..
Why orientation is not controlling location..In your example if only parallelism is given with nominal dimension..What would be the result.Please help me to understand..Thanks Again!
Parallelism only controls the orientation of the feature relative to the datum reference frame. It does not control the location of the hole. A position tolerance, however, must be centered on the true position (basic, theoretically exact dimensions)
Thank you 🙏🙏🙏🙏🙏
Teşekkürler. Süper bir örnek. Süper bir anlatım.
In this case, is there a difference if you called this out as a composite position DRF instead of a position DRF and a parallel DRF?
No difference on this example because there is only a single feature. The lower frame of a composite constrains rotational degrees of freedom only. This would control orientation only to the lower datums just like the parallelism.
However, composite position would be different if there were multiple holes. The lower frame of composite would also control location between the features in addition to orientation to the datums.
Hello - how do you determine the allowable position tolerance, thank you
For clearance holes: position tolerance can be calculated by the fixed or floating fastener formula (MMC hole-MMC pin). For an example like in this video: The calculation is "how much can you allow the hole to be misaligned". You need to zoom out and look at the overall assembly and decide how precise it needs to be to function.
It reminds me of a composite callout which I came across a few days ago, the drawing is provided by our customer tesla which means they are ASMY based.There are two rows in total, the first row is the profile 0.1 respect to datum A,B&C while the second row is only flatnes which is also required 0.1. Is it a correct call out for the second row, I don't think it does make sense .
For a drawing to ASME, any datum feature references in the lower tiers of a composite frame constrain in rotation only. It sounds like your frame does not have a datum feature references in the lower frame (so it does not matter if it is composite or not). The lower tier profile controls only size and form of the surface.
@@GeoTolPro Yes,the lower tier doesn't have a datum feature references,but shouldn't the lower tolerance be tighter than the top tier of a profile tolerance. In my case, both of them have the same tolerance which is 0.1.
Yes, the lower tier is a refinement so the tolerance value must be smaller to be effective. It sounds like a regular profile tolerance would suffice.
Great explanation! Would you mind explaining how to determine the position or perpendicular tolerance if a pin like a dowel pin and a hole use a interference fit? like Ø5 H7/p6, press fit. Would you use MMC with 0 tolerance for the tight tolerance like this? I'm not sure how to do this correctly? I've been haunted by this kind of problem for a while. Thanks!
The position or perpendicularity tolerance has no effect on the press fit. Size tolerance alone insures they press together. Position controls the relationship to other features on the part.
@@GeoTolPro Thanks!
Can't I use a composite position tolerance for this too ?
Yes, the lower segment of a composite tolerance controls orientation only to the datum reference frame. In this example it would be the same. However, I like parallelism on this simplistic one-feature example. I use composite position where it's pattern of features that also needs grouping.
Thank you mr tobey maguire :)