exercises geometric tolerances

[GunMaker]

I open this space to discuss the correct allocation of geometric tolerances in different mechanical details...I noticed that during the study (and on my textbook :frown: ) there is a lot of focus on the definition of geometric tolerances but never a real "method" or a "criterium" on how to allocate such tolerances logically and functionally or on how to place references. . .

In particular, I am asked to assign geometric, dimensional and quota tolerances (of course). .
I think you should start with the central body. ..according to you I made some mistakes in geometric references/tolerances?
(p.s sorry if some characters are bigger than others and some odds poorly arranged, I did not have time to review it)

Thank you in advance for the answers...

 

[MassiVonWeizen]

I have noticed that during the study (and on my textbook) there is a lot of focus on the definition of geometric tolerances but never a real "method" or a "critery" on how to allocate such tolerances logically and functionally or on how to place references. . .

method and criterion are given:
- from the legislation (obviously besides the explanation is given some examples, but to represent the various cases would serve a dozen treccani)
- from the funzinality of the piece (if you don't know what any tolerance you put will probably be wrong, if the guess is in contradiction to the side)
- from the machine on which they are carried out and on the working cycle (a cnc has precisions such that certain tolerances of geometrics are automatic, as a correct working cycle allows to perform work without moving the piece and therefore risk disalignment. )
- from experience and logic.
said this certain tolerances should be indicated because strictly necessary to the functionality of the piece; every tolerance requires control of the socket in the machine. sometimes during processing and subsequently for compliance, all these are additional costs in equipment, machinery, operator then putting a lot to the kilo is not a good thing because if on the one hand you para l'anfratto between the butts on the other you require a verification of said with swabs passes does not pass in crescendo by operators, owner workshop, final customer.

End pips.

(p.s sorry if some characters are bigger than others and some odds poorly arranged, I did not have time to review it)

but having made it to cad (as software in profile means cad, not the operating site) because not to use a standard quota size, as you did to make it one by type I can not understand it... that then the odds are poorly arranged is the least... I'm to see! ! !
Geometric tolerances without dimensional tolerances serve nothing (what do you do with a perpendicularity between two floors if after one of these is half a milimeter narrower than necesasary and dance like shakira after a plate of sausage and beans?
Ultimately it seems to me that you have taken equal tolerances from the dispenses and hit them on the drawing without reasoning more than that. analyze it carefully and think about what is functional and what is not