3/8 and Radial?

brandoncook26

brandoncook26

AzB Silver Member
Silver Member
I was told today that there is no real difference in a 3/8x10 , 3/8x11, and a Radial pin because they are all the same size going into the butt. Is this true? If it is not, what is the difference?

I play with a 3/8x11 brass, but a cuemaker I am talking with is trying to get me to use a radial pin and I have never played with one.

Thanks for the help.

-Brandon
 
pin

I don't recall the cue makers site, but he shows a cross section of a a shaft with different pins. A flat bottomed 10 or 11 I believe has the most contact, even slighlty more than a radial.
 
They are buried inside the cue when the cue is put together, and aside from weight considerations, no one on earth is going to be able to tell the difference in how the pins "play".
You find a someone that tries to tell you his pin "plays" better, you might want to take anything else they say with a grain of salt. :grin-square:

The difference is in the construction, and precision, and durability of the threads. The radial is likely to be superior to the others, with the 3/8-11 (acme style) being a close second. 3/8-10 can go be good, or not so good, depending on the quality of the pin, and installation methods. At least with the radial, installation is the only real challenge.
 
I think this may help...............
mod_pin.jpg


My understanding is that a Radial Pin provides the most pin to shaft contact area of any joint but I'm sure people would debate that all day long.
 
DiamondDave said:
I think this may help...............
mod_pin.jpg


My understanding is that a Radial Pin provides the most pin to shaft contact area of any joint but I'm sure people would debate that all day long.
Click to expand...

Looks to me that if the standard 3/8 X 10 shaft had been bored to a smaller diameter the wood threads would fill the threads very similar to the flat bottomed. Either way, it all boils down to precision in construction techniques. The flat bottom is a nice snug fit, same as a Radial but if the boring is off slightly, say, .0005 to small the shaft wont go onto the pin and if it's .0005 to large you end up with play and not much threads holding into the wood of the shaft. Just one more parameter for the cue builder to decide on when designing what is best for his cues.

Dick
 
rhncue said:
Looks to me that if the standard 3/8 X 10 shaft had been bored to a smaller diameter the wood threads would fill the threads very similar to the flat bottomed. Either way, it all boils down to precision in construction techniques. The flat bottom is a nice snug fit, same as a Radial but if the boring is off slightly, say, .0005 to small the shaft wont go onto the pin and if it's .0005 to large you end up with play and not much threads holding into the wood of the shaft.
Dick
Click to expand...

Dick, your first sentence is absolutely correct but please let me put it into perspective: The standard formula for determining tap drill size says that the hole should be .275 diameter. However, anyone trying that will find that maple will tear, leaving ragged, unsightly threads. Because of this, most cuemakers use a 5/16 drill (.3125 diameter), which permits the tap to cut a cleaner, nicer looking thread that is, unfortunately, sloppier than most people like. Standard fixes include swishing CA glue in the hole to tighten things up a bit.

In the photo shown, the bore on the left was .304 diameter, smaller than the std .3125, yet obviously still sloppier than the FB thread on the right.

And, Dick, your second sentence is also dead on: Construction techniques can make or break the precision being sought. Boring the hole is necessary to correct for a wandering drill bit but missing the size by even a little will be very noticeable. I suggest boring a critical hole like this to a few thou undersize & using a reamer to cut the final size. Reamers are available in any size you want and this simple, extra step provides both a true hole & an accurate size - time after time.

I'm sure someone has videos & pictures showing exactly how to do this :-)
 

Im sure youre aware of it even though you didnt mention it. When you look real close at the standard 3/8-10 its easy to see the difference between the threads the tap made and the threads on the screw.

Above the word standard you can see the void between the screw and the maple on the lead side of the major. Looking at the screw just above the word screw you can see the void is on the aft side of the major.

I wouldnt think the tap would have caused that condition so it must be the screw thats off. I could be wrong but that looks like a rolled thread. When those screws are made that rod goes through the die like ex-lax through a super model and they can stretch.

On the modified 3/8 its uniform all the way across. I would think the original question is answered by the photo. Good looking pin. Do you make those yourself?
 
TellsItLikeItIs said:
When you look real close at the standard 3/8-10 its easy to see the difference between the threads the tap made and the threads on the screw.

I could be wrong but that looks like a rolled thread. When those screws are made that rod goes through the die like ex-lax through a super model and they can stretch.

On the modified 3/8 its uniform all the way across. I would think the original question is answered by the photo. Good looking pin. Do you make those yourself?
Click to expand...

Yes, the std threads are rolled and although you make a good point, I'm not sure the irregularities you see are really as bad as they look. When I band sawed the wood in half, it may have distorted the thread form somewhat. Your contention that rolled threads can be distorted is correct. The point of the picture was to show the fit at the root of the threads rather than the actual matching of the thread form.

No, I don't make the pins. They are available through several of the billiard industry vendors.
 
A 3/8X10 screw hole starts with a 9/32" hole, not a 5/16". The ilustrations you posted look like they were produced by someone selling the 11 thread screws.
 
Yes, please. I have cues with radial and cues with 3/8-10 pins, and would like to see the difference shown this way.
 
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Paul Dayton said:
A 3/8X10 screw hole starts with a 9/32" hole, not a 5/16".
Click to expand...

Correction: it SHOULD start with a 9/32 hole. That's the proper size to use (.275/.281 = close enough). However, virtually everybody on this forum uses 5/16. Even the big name aftermarket shafts use a 5/16 hole. It's the easy way out. Kinda like rounding off the corners of joint faces. Or using black epoxy. Or...

Apologies to anyone who uses a hole smaller than 5/16. But I'd be surprised to hear if there were more than a handful.
 
i use a .308 hole which isn't really much smaller but a little.i am sure there are a few guys using .308 holes for the new pins and the tap with .308 pilot.

it makes the threads much tighter for those new 3/8-10 pins than a .312 hole and a standard tap.
 
3/8-10 tap drill size

When taping the thread hole for a 3/8-10 or 11 thread the standard tap drill charts do not apply. Technically speaking, when tapping into a non-ferrous material the thread classification is called "NC5INF". If you referred to Machinery's Handbook you would notice that a standard NC3 thread only covers about 2/3 of the thread depth while a NC5INF thread covers about 90 percent, which is reason they are called "Class 5 Interference-Fit Threads".
A 5/16" (.3125") tap drill is to large for this thread by a margin of .0065".
The correct drill size for this type of thread, in wood, is .306". This will give you a thread profile as shown in the right hand pic of DZ's sectional view.

As a practical application I drill the hole starting with a CNC spotting drill (solid carbide) and then with a .300" 3-flute carbide drill and finish off with a .305" (7.8mm) 3-flute carbide drill. Also note that different woods will give different results. Since most of my shaft holes are plugged with ebony or Katalox I feel comfortable with the above mentioned tap drill sizes for these woods. Maple may require some tweaking of the tap drill size to eliminate tear-out. When I do tap maple, PH or similiar woods I use CA glue in the
hole prior to tapping.
 
Everytime I see posts about thread contact I makes me wonder. If it is so neccesary for all that contact on a 4 oz shaft why is it not neccesary on a single part connected to a car? Connecting rod bolts are not radial thread. Cylinder head bolts are not radial thread. Main cap bolts are not radial thread. Rear carrier bolts are not radial thread. So why would a cue need more thread contact when the force is one-directional, not multi-directional as some car parts are and when the one-directional force is a fraction of what the load rating for said bolt (pin) is?
 
and then with a .300" 3-flute carbide drill and finish off with a .305" (7.8mm) 3-flute carbide drill
Click to expand...

i use the 3 flute carbide bits too and i find no reason or need to bore.i make a center hole and them drill with .290" 3 flute carbite bit and follow with .307 3 flute carbide bit and my holes are never more than .001"-.002" off and most of the time they are right on the mark.
 
i agree no one can pick out the different pins blindly. i also agree more contact area the better. so it makes sense that drilling a smaller hole for a better fit. however... i am not a fan of having a cue with the pin so tight you can barely get the shaft on or off. i saw a cue like that this weekend. i wont mention any names but i thought i was gonna split the wood it took that much force to get the shaft on and off. the noise was blinding. like nails on a chalkboard

reguardless its nice to see a thread WITH pics not just a blind debate. :wink::wink:
 
dave sutton said:
i agree no one can pick out the different pins blindly. i also agree more contact area the better. so it makes sense that drilling a smaller hole for a better fit. however... i am not a fan of having a cue with the pin so tight you can barely get the shaft on or off. i saw a cue like that this weekend. i wont mention any names but i thought i was gonna split the wood it took that much force to get the shaft on and off. the noise was blinding. like nails on a chalkboard

reguardless its nice to see a thread WITH pics not just a blind debate. :wink::wink:
Click to expand...

Hi, this happened to my cue along with a new shaft. It's too tight, I put candle wax on the male joint. After that, I can put the shaft on the butt with no problem. :)
 
bdcues said:
Everytime I see posts about thread contact I makes me wonder. If it is so neccesary for all that contact on a 4 oz shaft why is it not neccesary on a single part connected to a car? Connecting rod bolts are not radial thread. Cylinder head bolts are not radial thread. Main cap bolts are not radial thread. Rear carrier bolts are not radial thread. So why would a cue need more thread contact when the force is one-directional, not multi-directional as some car parts are and when the one-directional force is a fraction of what the load rating for said bolt (pin) is?
Click to expand...

Whoever said pool players were logical? Part of the difference is that automotive parts are usually assembled once & only once.

A cue is assembled & disassembled every time it will be used in battle. Any sloppiness detected during this ritual can be perceived as a weakness if the warrior is so inclined.

Seriously, though, a better fit should translate into longer thread life despite the repeated use.

Side note: this PM, I tried high speed tapping a 9/32 hole in maple with a lubricated 3/8-10 tap & got very good results. There was still a slight bit of tearing but overall, it looked good. Perceived fit was no better but thread form was definitely more full. I can post a pic if there's still any interest in this thread.
 
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