We have a job that details a square taper as...
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.50 PF LARGE END
OF SQUARE .75
PER FOOT TAPER
(TOTAL)
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The "PF" is throwing me off. I'm assuming Press Fit?
Never seen it detailed like that before.
TIA ~CH
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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
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
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