Coincidence between a hole in a shaft and a tooth on the outside.
Coincidence between a hole in a shaft and a tooth on the outside.
(OP)
I have a shaft that has five teeth equally spaced around the outside of the shaft. There is also a hole drilled thru the shaft perpendicular to the axis. The hole is used to index the shaft in reference to one of the teeth. The origin of this part dates back to the early 60's in which the print then had a note stating "centerline of the tooth thru the axis of the shaft and the centerline of the hole to coincide within +/- 0 degrees 15 minutes".
I am trying to determine the correct way to define this using GD&T. Attached is a sketch of my first thought, but I am not sure if it is correct or the best way. Datum A is the center of shaft bore. Datum B is the end of the shaft. Datum C is the profile of one tooth which should give me the axis of the tooth. The .002 parallel to C in the control frame is equal to 30 minutes of angle. Which now I am thinking should be .001 or 15 minutes.
Does this sketch seem correct or is there a better way? Or should I put a note under the control frame stating axis of C and axis of hole to be coincident within +/- 15 minutes.
Thanks in advance.
Ron
I am trying to determine the correct way to define this using GD&T. Attached is a sketch of my first thought, but I am not sure if it is correct or the best way. Datum A is the center of shaft bore. Datum B is the end of the shaft. Datum C is the profile of one tooth which should give me the axis of the tooth. The .002 parallel to C in the control frame is equal to 30 minutes of angle. Which now I am thinking should be .001 or 15 minutes.
Does this sketch seem correct or is there a better way? Or should I put a note under the control frame stating axis of C and axis of hole to be coincident within +/- 15 minutes.
Thanks in advance.
Ron





RE: Coincidence between a hole in a shaft and a tooth on the outside.
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: Coincidence between a hole in a shaft and a tooth on the outside.
I actually was just thinking about changing the control frame to three lines.
True position| .002| A | C | This line to prevent the location from getting too far from axis of tooth or bore.
True position| .005 | B | This line to give a little more freedom along the length of the shaft.
Parallel |.001 | C This line to control angle to the tooth.
RE: Coincidence between a hole in a shaft and a tooth on the outside.
RE: Coincidence between a hole in a shaft and a tooth on the outside.
RE: Coincidence between a hole in a shaft and a tooth on the outside.
RE: Coincidence between a hole in a shaft and a tooth on the outside.
Actually, not so many
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: Coincidence between a hole in a shaft and a tooth on the outside.
Even a tooth thickness caliper doesn't have a unique orientation.
RE: Coincidence between a hole in a shaft and a tooth on the outside.
I assume you have no problem dealing with concept of hole axis, which is imaginary, just like CL of tooth profile?
Naturally, all the sophisticated instruments leave the place for simple techniques like this: http://www.eng-tips.com/viewthread.cfm?qid=111643
Let me repeat, dealing with tooth thickness / center plane may be easier than you make it to look like.
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: Coincidence between a hole in a shaft and a tooth on the outside.