Spurs
Mechanical
- Nov 7, 2002
- 297
I have a customer drawing that was created by a group in Detroit. They did the GD&T. But of course the customer SQA person is in Mexico. They have a different interpretation of how a gage should be built for this - I am caught in the middle although I agree with the Detroit Engineer. Could I be wrong?
Here is a section of the part drawing
The control frame for true positon has two lines in the callout. The engineer and I interpret this control frame to mean that if we use gages to measure this (as opposed to CMM) we need 2 gages.
The first gage would have a pin at the mmc size of datum A 12.065 sticking out of a plate (DATUM B) Then around that pin would be 6 other pins spaced 60 degrees apart at a bolt circle of 40 mm. These 6 pins all have a size of 5.1-.05 (hole size tolerance) - .2 (true positon tolerance)= 5.85 mm. The part must fit over this gage into all holes simultaneously.
The second gage would be similar except there is no datum A pin and the 6 pins have a size of 5.1-.05 (size tolerance) -.05 (true positon tolerance)= 5.0 mm.
The Mexican SQA says it is only a single gage similar to the first one I mentioned except the size of the 6 pins is 5.10 - .05 (size tolerance) - .2 (first position tolerance) - .05 (2nd position tolerance) = 4.8 mm diameter pins.
Which is correct ?
On another note: Does the 6x marking automatically tell you to combine all 6 holes into the measurement simultaneously? one other person suggested that the first line of the control frame means that you build a gage with the datum A pin at 12.065 and only a single pin at 5.85. Then you test each of the 6 holes individually. My assumption is that the 6x implies that the holes are to be treated as one group. Is this true or just an assumption?
Here is a section of the part drawing
The control frame for true positon has two lines in the callout. The engineer and I interpret this control frame to mean that if we use gages to measure this (as opposed to CMM) we need 2 gages.
The first gage would have a pin at the mmc size of datum A 12.065 sticking out of a plate (DATUM B) Then around that pin would be 6 other pins spaced 60 degrees apart at a bolt circle of 40 mm. These 6 pins all have a size of 5.1-.05 (hole size tolerance) - .2 (true positon tolerance)= 5.85 mm. The part must fit over this gage into all holes simultaneously.
The second gage would be similar except there is no datum A pin and the 6 pins have a size of 5.1-.05 (size tolerance) -.05 (true positon tolerance)= 5.0 mm.
The Mexican SQA says it is only a single gage similar to the first one I mentioned except the size of the 6 pins is 5.10 - .05 (size tolerance) - .2 (first position tolerance) - .05 (2nd position tolerance) = 4.8 mm diameter pins.
Which is correct ?
On another note: Does the 6x marking automatically tell you to combine all 6 holes into the measurement simultaneously? one other person suggested that the first line of the control frame means that you build a gage with the datum A pin at 12.065 and only a single pin at 5.85. Then you test each of the 6 holes individually. My assumption is that the 6x implies that the holes are to be treated as one group. Is this true or just an assumption?
