Special Metric Threads

[nornrich]

All,

We are measuring up a metric part and have come across a M52 Thread that has a pitch of 1.25 tpi. It looks like this might be custom, but I wanted to see if anyone heard of this type of thread.

Regards,

Rich....

Richard Nornhold, PE

 

[reidh]

I have heard of M52x2, 3, and 4. Never 1.25. I also assume that 1.25 is the metric pitch (which is really mm/thread, not TPI). A 1.25 tpi would be approximately an M52 x20.

-Reidh

 

[unclesyd]

Nothing I have goes below M52-1.5m.

 

[rmw]

Something is wrong here. What is tpi? Threads per inch? If so, then it is not a metric dimension. I have seen 1.25 as a metric pitch but I don't think it was in a size as large as 52mm. I think I remember it in like a size M8. The more I think about it, I am sure it was M8. A 1.25 metric pitch would be a pretty fine thread for a 52mm dia.

What is wrong here?

rmw

 

[nornrich]

Sorry for the confusion instead of 1.25 tpi it should be 12 threads per inch.

Rich....

Richard Nornhold, PE

 

[rmw]

Then that would be the M52 x 2 that reidh mentions above, although nothing that I googled showed that fine of a thread in size M52. As a 5 pitch is the standard metric course thread size for that diameter, a 2 pitch seems very fine for that size. But I'll take reidh's word that it exists.

rmw

 

[reidh]

M52 x 2 is used on "Bite" fittings. Not very common, but they are around.

http://www.parker.com/tfd/cat/pdffiles/F-EO-EO2/ew.pdf

-Reidh