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Involute cutter identification.

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  • John Stevenson
    replied
    Both,
    Works out the same.
    tiffie has just repeated what Joe said earlier.

    Leave a comment:


  • Terry L
    replied
    Okay, so who's right ? Optics Curmudgeon or Old Tiffie ?

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  • oldtiffie
    replied
    Pa = 14 1/2*

    Originally posted by Peter.
    Can you identify the pressure angle of an involute cutter from the DP and depth as marked?

    A No2 cutter, 12DP, depth marked as .1798 - I need a 20PA cutter.
    Depth of cut for 14 1/2* PA = 2.157/DP = 2.157/12 = 0.1795"

    Depth of cut for 20* PA = 2.25/DP = 2.25/12 = 0.1875"

    The cutter PA is 14 1/2*

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  • Peter.
    replied
    Right-o, thanks. Saved me finding out the hard way

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  • Optics Curmudgeon
    replied
    That one sounds like a 14.5 degree one, the full depth of a 14.5 degree tooth is 2.157/pitch, for 20 degrees it's 1.800/pitch.

    Joe

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  • John Stevenson
    replied
    Usually if they are not marked they are 14.5 degrees, but that's not 100%

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  • Peter.
    replied
    Bugger

    The PA is not marked on the cutter. Is there no other way to tell?

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  • The Fixer
    replied
    No....

    The DP (Diametral Pitch)is based on the diameter of the pitch circle and the No. identifies the range of gear teeth that the cutter is able to cut.
    if u do a search here for cutting gears u will see there's been considerable discussion on the topic.
    The PA determines the profile of the teeth based on the angle of contact of the meshing teeth. it usually says on the cutter what the PA, DP and No. is.

    Leave a comment:


  • oldtiffie
    replied
    'fraid not

    Probably not. Thet are usually either 14 1/2* or 20*

    This is how it is marked on the cutter:


    http://en.wikipedia.org/wiki/Milling...te_gear_cutter

    Leave a comment:


  • Peter.
    started a topic Involute cutter identification.

    Involute cutter identification.

    Can you identify the pressure angle of an involute cutter from the DP and depth as marked?

    A No2 cutter, 12DP, depth marked as .1798 - I need a 20PA cutter.
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