difference in 3/8 10 and 3/8 10 modified
- Thread starter Rico
- Start date
You have been told different answers because there are different answers.
If the hole in your "normal" 3/8-10 shaft was drilled/bored large enough for the minor diameter of the FB pin (they vary...you didn't say which FB pin), then yes. If not, then no, the hole in the shaft will have to be enlarged appropriately.
Usually, the OD of the threads in the shaft are not a limiting factor.
If the hole in your "normal" 3/8-10 shaft was drilled/bored large enough for the minor diameter of the FB pin (they vary...you didn't say which FB pin), then yes. If not, then no, the hole in the shaft will have to be enlarged appropriately.
Usually, the OD of the threads in the shaft are not a limiting factor.
This.
The "modified" 3/8-10 pin has a larger minor diameter. Because of this, the modified pin will not go into most standard holes, but the standard pin will fit into either the modified or non-modified hole. Not necessarily correct but will work.
The non-modified 3/18-10 hole SHOULD have a minor diameter between .267"-.288". The modified pin is usually machined to a .308" minor diameter. A standard 3/8-10 pin should have a minor diameter somewhere around .265".
Anybody wishes to correct me, go ahead. Knowledge is power. Wrong knowledge is useless.
Not that it matters since too small is too small, but your hole numbers are off, especially your .265". Running a standard 3/8-10 tap in a .265" hole would be a no go. The standard tap drill for a 5/16" thread is F drill, .257", nearly the same as your suggested .265" minor diameter.
Usually a reamer is all that is necessary for enlarging the hole. (Reamers are designed to remove only a small amount of material.) Most of the holes for standard 3/8-10 pins seem to dance around .300", when they are too small for an FB pin.
Edit: I'm not going to change what I wrote as I prefer things we say, even when not completely accurate, should stand. I was just informed by a cuemaker (thanks) with a longer history and experience than myself than the old school 3/8-10 pins had a minor in the neighborhood of .280-.285. My personal experience in recent years when enlarging holes so shafts would screw onto the FB pins is the holes were not that small.
Usually a reamer is all that is necessary for enlarging the hole. (Reamers are designed to remove only a small amount of material.) Most of the holes for standard 3/8-10 pins seem to dance around .300", when they are too small for an FB pin.
Edit: I'm not going to change what I wrote as I prefer things we say, even when not completely accurate, should stand. I was just informed by a cuemaker (thanks) with a longer history and experience than myself than the old school 3/8-10 pins had a minor in the neighborhood of .280-.285. My personal experience in recent years when enlarging holes so shafts would screw onto the FB pins is the holes were not that small.
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So, if I’m reading this correctly, a shaft threaded for modified 3/8-10 will also work with a cue with a standard 3/8-10 thread. A standard 3/8-10 shaft however will not work with a modified 3/8-10 pin?
Thank you!
I've always viewed the modified pin as a modified acme style thread. I use a 3/8-11 modified/modified pin. Well it's not really a 3/8 because it's been modified to smaller major and minor diameters and that's why it carries the distinction of being a modified/modified pin.
However, the reason I like the modified style pin is a debate for a different subject that apparently goes against all machining theory ever put in print.
But to answer your question, one may fit the other and the other may not fit the one. They can though be easily made to be able to both fit with proper tooling and a little bit of knowledge.