today i made a big error in my assembly, as i got a key distance wrong. this mistake leaded to some wastes. in fact, i had defined this key dimension at first. but later, i adjusted a dimension of one key part, which leaded to a change of that key distance. unfortunately , i didn't notice it at all and handed out my drawing.  i have been thinking of a method to fix that key dimension so that i can adjust other dimension without worry about my key dimension.

thank you! and i am so eager to make some friends on this forum. my e-mail address: tuzianjing@163.com    my yahoo account: grace. comeon