Pitch Option For Auto Circles

[#2#]

Having recently learned about using the pitch option I have a question. In the Auto Circle window entering the pitch of a thread causes the probe to take hits in a progressive fashion to follow the thread.

I have a right hand thread that is oriented such that I must measure it with tip A90B90. The vector of the circle is 0,-1,0. When I entered a positive pitch the hits were taken by moving the tip +Y in between hits. This was the wrong direction. I entered a negative pitch and it moved correctly.

Does the sign (+ or -) have to match the vector of the hole?

With this particular thread it was not a problem as it is external and I can see the probe moving properly. Coming up I have a small (8-32) internal thread. I don't think I will be able to tell if it is moving in the correct direction.

Any suggestions?

[John Kugler]

I believe the probe will follow the vector of the hole as it probes along the pitch. So if you have a 0, -1, 0 the probe went in the - direction. What I do is flip the vector so the vector is coming out the hole, and put my probe deeper into the hole so it will probe as if it is coming out of the hole. I also change my start angle to 0 and my end angle to 720. This allows the probe to go around the hole twice to ensure an accurate measurement.


Hope this helps....

[#2#]

Thanks for the tip. I think I had figured out that the sign needs to match the vector's sign for a right hand thread. I guess the other thing that threw me off was the rotation of the probe. If it changes from clockwise to counter clockwise the sign for the pitch needs to change.

I think for now I will just create the circle with a large pitch .2 and see that it is moving correctly and then go back and edit the pitch.

Good tip about measuring more than once around.

I am attempting to use pitch with an auto cylinder now.

[bob mappes]

another way is to go the negative direction of travel, without messing with the vectors

start angle at 0 degrees
end angle at -360 degrees


bob