【转帖】gdt help

yang686526

gd&t help
hello,
i need to know how to use gd&t to dimension a shaft(r=5, l=14) assuming two cases:
1) it will be mating inside a cylinder(already dimensioned and tolerenced)
2) it will not be mating with anything
can anyone give me a general overview of what tolerencing i need for both cases?
thanks
k
this is hardly enough input to make any dimensioning determinations.  
it would seem that you are somewhat a novice to the world of asme y14.5 and a course would be appropriate.  
thanks,
yes i am a novice in gd&t, hence the reason for signing up to this forum and asking for some advice.
maybe you could let me know what other input i would need to make a useful dimensioning determination?
k
you will need to know the class of fit you are needing.  that would be based on the function of the parts interacting.
in your post, you inply there are 2 different setups.  that requires some clarification too.
even with that information you will need a basic understanding of the language before you can successfully apply it.
do a search on this site...here is a link to something along the line of what you're doing
koror,
   all you need to do to make the shaft fit in the hole is to set the dimensions and tolerances to make the hole smaller.  this is straight arithmetic.  the ansi fit classes will help you to work out appropriate clearances.
   it sounds like you need some formal training.  perhaps you should take a look in a machinery's handbook.
                      jhg
thanks,
this gd&t is new to me...i studied as a mechanical engineer but never had to use tolerencing in any of my designs.
machinist handbook sounds like a good idea...any suggestions?
-k
never had to use tolerancing? good time to start. all parts and there dimensions have a tolerance.
all mechanical engineers should have a copy of the machinist handbook somewhere.
chris
sr. mechanical designer, cad
solidworks 05 sp2.0 / pdmworks 05
i first became familiar with the machinery's handbook back in high school (almost thirty years ago).  i consider it an essential part of any design library, and if you don't have a copy, i highly recommend that you get one.  some of the new ones are on cd.
as far as gd&t is concerned, getting a copy of the standard and some training would be very beneficial.