Daave
Aerospace
- Nov 3, 2011
- 3
Hello All,
I keep coming across this issue and I wanted some opinions. I have a cover plate that fits over a D03 pattern. I want to use GD&T to control the locations of the holes relative to the mounting pattern. The sides need not be controlled within reason. My main question is can I use the 4 mounting holes as a pattern by saying "4X" which would give you two perpindicular planes at their centers and make them datum "B"? If yes do I require a note? Also, notice that the upper mounting holes and the lower mounting holes are spaced different but still on the same perpindicular centered datums. I would then make the rest of the holes go back to A & B? Using composite I could tighten up the o-ring bores and the pressure port not blocked off relative to each other? I am thinking of removing the profile tolerance for the perimeter to simplify.
It is also worth noting that keeping this as simple with minimal GD&T as possible may reduce costs and lead time. While good GD&T reduces costs and opens up tolerances it still is a issue today that machine shops still do not have a grasp on tolerancing and it take smore of their time to read a drawing an thay therefore add additionall costs at times. I found using composite tolerances is one of those times. Although it depends on the source/shop. I can not complain as I need assistance as well after several years of using GD&T.
I have attached a rough draft of my approach. Can it be simplified? Is it correct?
Thanks for the comments.
I keep coming across this issue and I wanted some opinions. I have a cover plate that fits over a D03 pattern. I want to use GD&T to control the locations of the holes relative to the mounting pattern. The sides need not be controlled within reason. My main question is can I use the 4 mounting holes as a pattern by saying "4X" which would give you two perpindicular planes at their centers and make them datum "B"? If yes do I require a note? Also, notice that the upper mounting holes and the lower mounting holes are spaced different but still on the same perpindicular centered datums. I would then make the rest of the holes go back to A & B? Using composite I could tighten up the o-ring bores and the pressure port not blocked off relative to each other? I am thinking of removing the profile tolerance for the perimeter to simplify.
It is also worth noting that keeping this as simple with minimal GD&T as possible may reduce costs and lead time. While good GD&T reduces costs and opens up tolerances it still is a issue today that machine shops still do not have a grasp on tolerancing and it take smore of their time to read a drawing an thay therefore add additionall costs at times. I found using composite tolerances is one of those times. Although it depends on the source/shop. I can not complain as I need assistance as well after several years of using GD&T.
I have attached a rough draft of my approach. Can it be simplified? Is it correct?
Thanks for the comments.
