iSixSigma

Why do we double hypotenuse when doing TP calcs?

Six Sigma – iSixSigma › Forums › Old Forums › General › Why do we double hypotenuse when doing TP calcs?

Viewing 3 posts - 1 through 3 (of 3 total)
  • Author
    Posts
  • March 13, 2007 at 3:45 pm #46401

    Ropp
    ★ 10 Years ★
    Participant

    I know this is the convention, but someone asked me this today and I can’t honestly think of a good reason why. Digging out my GD&T handbook I can see that in every example we use the pythagorean theorum, then multiply by two to get the true out of tolerance calculation.
    I’m sure this has something to do with the difference between diameters and radii, but I’m not sure why. Can someone give me a quick explanation? My CMM can tell me the difference between the calculated center of a hole and the theoretical. Why are we doubling the distance from centerline to centerline?

    0
    March 13, 2007 at 4:47 pm #153235

    BTDT
    ★ 10 Years ★
    Participant

    Dave:Tp is a diameter, calculations are in radii.Found it here with a single search using the string “Tp Calcs gd&T”http://www.pcdmisforum.com/showthread.php?t=3659&page=4Cheers, BTDT

    0
    March 13, 2007 at 5:13 pm #153237

    Jim Shelor
    ★ 10 Years ★
    Participant

    When using a triangular distribution you need to calculate the upper endpoint, lower endpoint and the mode.
    If you assume the mode is in the center, you would simply calculate either the upper or the lower endpoint and multiply by 2.

    0
  • Author
    Posts
Viewing 3 posts - 1 through 3 (of 3 total)

The forum ‘General’ is closed to new topics and replies.