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  1. #1

    Question OLD BLUEPRINT DIMENSION QUESTION.

    We have a job that details a square taper as...
    ______________________

    .50 PF LARGE END
    OF SQUARE .75
    PER FOOT TAPER
    (TOTAL)
    ______________________

    The "PF" is throwing me off. I'm assuming Press Fit?

    Never seen it detailed like that before.

    TIA ~CH

  2. #2
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    Re: OLD BLUEPRINT DIMENSION QUESTION.

    Quote Originally Posted by CEMENTHE4D View Post
    We have a job that details a square taper as...
    ______________________

    .50 PF LARGE END
    OF SQUARE .75
    PER FOOT TAPER
    (TOTAL)
    ______________________

    The "PF" is throwing me off. I'm assuming Press Fit?

    Never seen it detailed like that before.

    TIA ~CH
    The PF is per foot taper without seeing the drawing it does not make much sense the way that this is written
    Mactec54

  3. #3

    Re: OLD BLUEPRINT DIMENSION QUESTION.

    Quote Originally Posted by mactec54 View Post
    The PF is per foot taper without seeing the drawing it does not make much sense the way that this is written
    It's written exactly the way I typed it out. only thing missing is the Arrow pointing to the square on the end of a shaft.

  4. #4
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    Re: OLD BLUEPRINT DIMENSION QUESTION.

    Quote Originally Posted by CEMENTHE4D View Post
    It's written exactly the way I typed it out. only thing missing is the Arrow pointing to the square on the end of a shaft.
    Is there a thread involved
    Mactec54

  5. #5

    Re: OLD BLUEPRINT DIMENSION QUESTION.

    Quote Originally Posted by mactec54 View Post
    Is there a thread involved
    .375-16 UNC 2A on Square end and a 1.5-4 acme on the shaft.

  6. #6
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    Re: OLD BLUEPRINT DIMENSION QUESTION.

    Quote Originally Posted by CEMENTHE4D View Post
    .375-16 UNC 2A on Square end and a 1.5-4 acme on the shaft.
    It makes a little more sense the PF is not per foot it is a reference to a Thread JIS PF series thread so it is basally saying a Parallel Pipe thread, but your threads don't match up to that so still unknown as to what they mean, unless the thread was changed at some time, what is this drawings origin
    Mactec54

  7. #7

    Re: OLD BLUEPRINT DIMENSION QUESTION.

    snippet

  8. #8
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    Re: OLD BLUEPRINT DIMENSION QUESTION.

    I could be wrong but in my mind I'm thinking the .50 PF designates Press Fit. There is already a taper per foot callout (.75), hence the reason for such a tight tolerance at the small end of the square and finish callout as well. If I had to guess I would say that square gets press fit into a mating part and yet another part screws on the end to hold it in place.

  9. #9
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    Re: OLD BLUEPRINT DIMENSION QUESTION.

    Quote Originally Posted by z369 View Post
    I could be wrong but in my mind I'm thinking the .50 PF designates Press Fit. There is already a taper per foot callout (.75), hence the reason for such a tight tolerance at the small end of the square and finish callout as well. If I had to guess I would say that square gets press fit into a mating part and yet another part screws on the end to hold it in place.
    It's a Taper so would not be a press fit designed like it is, that also has a large tolerance +/- .010" .50= 2 decimal places=+/- .010"

    Looking at the drawing snip I would say the drawing was changed at some time and this is a mistake as it does not reference anything

    PF designates a JIS parallel pipe thread
    Mactec54

  10. #10
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    Re: OLD BLUEPRINT DIMENSION QUESTION.

    Hi - This wiki says PF is press fit. Peter

    https://en.wikipedia.org/wiki/Engine...ns_and_symbols

  11. #11
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    Re: OLD BLUEPRINT DIMENSION QUESTION.

    Quote Originally Posted by peteeng View Post
    Hi - This wiki says PF is press fit. Peter

    https://en.wikipedia.org/wiki/Engine...ns_and_symbols
    It is not going to be a Press Fit with a +/- .010" tolerance

    Note how it is used P.S. = Press Fit not just straight PS = Parallel thread for Jis standard, so it has more than one meaning depending on how it is written and what it is referring too

    I wonder if the Machinery Hand Book has how it should be used
    Mactec54

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