【转帖】positional issues, sorry if this is a repos

yang686526

positional issues, sorry if this is a repost.
my problem is this,
i have 2 bushings aligned to each other with a shaft running through their centers. when i measure on the cmm it's telling me the back bushing is out of position to the front bushing but they are bored on the same axis. i've indicated my chuck and it's running perfect. the back bushing call out is dia. 0.05m e(which is front bushing)m b(which is a perpendicular flange) see below for my lame sketch.
    0---|-0   
        ^ ^
        b e
any help would be great guys.
rob.
check out our whitepaper library.
have you just applied a diameter tolerance or have you added a positional diameter tolerance?
could the forces involved with the machining operation be causing deflections?
ja500 - the print calls out for both a diameter tolerance on the bushing as well as a dimensional tolerance to the front bushing (datum e)
mint - not likely. if there is deflection i would see that in the form of a taper would i not?
from your diagram it shows that the bush that is out is the longest of the two bushes.
if this is the case and you are using the smallest bust to datum from (e) then this may indicate that the perp flange may be incorrect as the larger bore would emphasise this.
is the flange check against any other features?