What is the difference between 3/8-11 and 3/8-10 screws?
Thanks
Thanks
Difference between 3/8-10 and 3/8-11
- Thread starter molly's boy
- Start date
The first number (3/8) is the screw's diameter in inches.
The second number (11 or 10) is the number of threads per inch of length.
pj
chgo
1 TPI and 6 thou in diameter.
One extra thread per inch
Are you sure?
I didn't think all 3/8 pins were the same diameter...
Example I recently read in the cuemaker forums
That would depend on which 3/8x14 you actually have. It's been around a long time. The next task would be having the correct tap for the one you need.
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It's never as easy as we think.
Cue builders are notorious for using non standard tooling. My wood pin is 1/2"-10-1/2. I suppose in the OP case the call out for the diameter is a nominal figure. Something close to 3/8" so just keep it simple.
Patrick and others are correct for standard tooling. 3/8 is the diameter and the number coming after is the pitch.
They are if they're truly 3/8 pins. That's what that number is supposed to mean .
pj
chgo
If 3/8 does not mean 3/8 why would that be stated as a screw diameter? it either is or it is not. 10 or 11 is just supposed to mean one more thread per inch period. Why would there be any confusion on stated numbers?
Maybe Kim will chime in, I certainly am not an expert on anything, could be mistaken, which was why I phrased my comment in the form of a question. Sorry for any contusion
Same reason a 2x4...isn't.
3/8 is the nominal size and regardless, the different threads per inch is all we need to know to know they don't mate.
Sent from the future.
Not true. I can give you two pins that are both exactly 3/8-10. One will fit and one won't. If the minor diameter is off by more than a few thousandths of a inch it could mean the difference between fitting loosely to being so tight you can't screw it together.
I was simply comparing a "standard" 3/8-10 Modified pin (wich seems to be the most used 3/8-10 pin by custom cue makers) to a "standard" 3/8-11 pin you can buy from the most common places out there. But you can find 3/8 pins that varies hugely from the .308" minor of the 3/8-10 flat bottom pin. Mr. Webb knows alot more about this than me.
I did a shaft for a McDermott here the other thay, if memory serves me right the hole was .285"
Screws have a "major diameter" which is essentially the outer diameter of the threads. This is typically the diameter given in the name. So a 3/8 screw is 3/8" diameter at the tips of the threads. The "minor diameter" is the diameter of a screw at the base of the threads...at the bottom of the "V". This varies from screw type to screw type. For example, the traditional V groove 3/8-10, like a McDermott, has the same major diameter as a 3/8-10 "modified" screw, but the 3/8-10 modified has a larger minor diameter.
From a machining standpoint, think in terms of the hole you would drill prior to tapping. A traditional 3/8-10 screw has a smaller drill size hole, and the threads are fuller. A 3/8-10 modified screw has a larger drill size hole, and the threads are shallower.
So while the major diameter (outer diameter) of a 3/8-10 and 3/8-11 screw are close to the same, the minor diameters are not. Compared to the traditional 3/8-10 screw like McDermott, the 3/8-11 screw has a larger minor diameter.
Also, it is easy to see that the shape of the thread differs from screw to screw. Some screws, like most 3/8-10 modified and 3/8-11 pins, have a flat bottom, so only the thread itself has a "point" to it, and the minor diameter surface is flat, as opposed to inverted V shape.
Hope this helps,
KMRUNOUT
From a machining standpoint, think in terms of the hole you would drill prior to tapping. A traditional 3/8-10 screw has a smaller drill size hole, and the threads are fuller. A 3/8-10 modified screw has a larger drill size hole, and the threads are shallower.
So while the major diameter (outer diameter) of a 3/8-10 and 3/8-11 screw are close to the same, the minor diameters are not. Compared to the traditional 3/8-10 screw like McDermott, the 3/8-11 screw has a larger minor diameter.
Also, it is easy to see that the shape of the thread differs from screw to screw. Some screws, like most 3/8-10 modified and 3/8-11 pins, have a flat bottom, so only the thread itself has a "point" to it, and the minor diameter surface is flat, as opposed to inverted V shape.
Hope this helps,
KMRUNOUT
Easy
Not much.
Nick
Not much.
Nick
Too many bastard 3/8 10 before you even deal with 3/8 11.
My tap only needs .295" sized hole.
There are also two kinds of 3/8 10 flat bottom floating around.
BCM's version has a smaller minor.
There are a few 3/8 11 as well.
The SW is less than .308 minor, but the most commonly used one has .308.
I didn't want to deal with that . Mine has a true .3125 minor.
Sugar Tree's 3/8 10 has a true .3125 minor as well.
Barenbrugge's 3/8 is actually a little smaller .
In a perfect world, all 3/8 screws would have a .3125 minor .
Of course, they are really not 3/8 because they are some .381" major.