The short answer
A pool cue joint is named for its pin: diameter, then threads per inch. A 3/8×10 pin is 3/8 inch across with 10 threads per inch. Radial and Uni-Loc are named designs rather than plain sizes: a radial pin has a rounded thread profile, and Uni-Loc is a quick-release joint.
For most players the joint matters less for feel than for fit. If you want a new shaft, or want your old shafts to fit a new butt, the pin and the insert must match exactly.
How pool cue pins are named
PoolDawg puts it simply: in 5/16×14, the 5/16 is the pin diameter in inches and the 14 is the number of threads per inch. On a short pin, count the threads across half an inch and double it (PoolDawg).
Two pins can share a diameter and still not fit, because the thread count differs. And two cues with the same pin can have different collar diameters at the joint face. PoolDawg passes on McDermott’s advice to measure the collar with calipers: steel collars usually measure around .843 inch, and many non-steel McDermott joints around .855.
| Pin | What it means | Notes |
|---|---|---|
| 5/16×14 | 5/16 in diameter, 14 threads per inch | A traditional fine pin; count threads to confirm |
| 5/16×18 | 5/16 in diameter, 18 threads per inch | Same diameter as 5/16×14 but not interchangeable |
| 3/8×10 | 3/8 in diameter, 10 threads per inch | PoolDawg lists McDermott cues on this pin |
| Radial | About 3/8 in, rounded thread bottoms | PoolDawg lists Jacoby; some 3/8×8 pins look similar but are V-groove |
| Uni-Loc | A named quick-release joint, not a plain size | Fits only Uni-Loc shafts; PoolDawg lists Lucasi |
Radial, Uni-Loc and quick-release joints
A radial pin has threads with a rounded bottom rather than a sharp V. PoolDawg warns that some 3/8×8 pins look similar but have a V-groove thread, so check the profile before you buy a shaft sold as radial.
Quick-release joints use a partly threaded or locking design so the cue comes apart in a turn or two. Wikipedia lists Uni-Loc, Accu-Loc, Speed-Loc and Tru-Loc among them (Wikipedia). They are convenient, but each fits only its own matching shafts.
Joint materials: steel, phenolic and wood to wood
The joint collar can be stainless steel, brass, plastic or phenolic, or the cue can be built wood to wood, with the shaft seating directly against the forearm. Wikipedia notes that wood-to-wood joints are used on carom cues and on some high-quality two-piece pool cues.
Players often say a steel joint feels firmer and a wood-to-wood joint softer or more connected. That is real for some people and hard to measure for others. If you already like how your current cue feels at the hit, the simplest answer is to match its joint.
How to identify the joint on your cue
- Check the brand and model. Many makers use one joint across a line, and the maker or retailer can tell you.
- Measure the pin. 5/16 inch is about 7.9 mm and 3/8 inch about 9.5 mm. Calipers settle it in seconds.
- Count the threads. Count across half an inch and double it.
- Look at the thread profile. Rounded bottoms suggest radial; sharp V threads do not.
- Measure the collar. A shaft has to match the joint face as well as the pin.
- Send photos. A clear photo of the pin and the shaft insert is often enough for a maker to identify it.
Which joint should you choose?
If you own shafts you like, choose the joint that fits them. That is the whole decision. If you are starting fresh but might add a carbon shaft later, pick a pin that shaft is sold for, so you are not boxed in when the time comes.
If you have no shafts and no plans, choose by feel and convenience: a quick-release joint for fast breakdown, a traditional threaded pin if you prefer it, wood to wood if you like the feel. For the rest of the spec, see our guide on how to choose a pool cue.
From the bench
We cut Radial, Uni-Loc, United, Wavy 1, Wavy 2 and 3/8 x 11 joints. If you already own shafts you want to keep using, this is the one choice we ask you to get exactly right: tell us what your current cue takes and we cut the same thread, so your shafts still fit.
If you are not sure what you have, send us a clear photo of the pin and the insert and we will help you work it out before anything is cut. It is a two-minute question that saves a lot of trouble, and you can start it from our build your own page.
Quick answers
What does 3/8×10 mean on a pool cue?
It describes the joint pin: 3/8 inch in diameter with 10 threads per inch.
What is a radial pin on a pool cue?
A radial pin has threads with a rounded bottom rather than a sharp V. Some 3/8×8 pins look similar but use a V-groove thread, so check before buying a shaft.
Can I put any shaft on my pool cue?
No. The shaft insert must match your pin’s diameter, thread count and thread profile, and ideally the collar diameter too.
How do I find out what joint my cue has?
Check the maker and model, measure the pin diameter, count threads across half an inch and double it, or send clear photos of the pin and shaft insert to the maker or a retailer.
Sources and further reading
How this guide was made: drafted with AI assistance from the sources above and the Muraki workshop’s own build notes, then published by the workshop. Anything about how we build is our own practice; figures from other people are credited. Spot something wrong? Tell us and we will correct it.
Want one built your way?
Tell us the wood, the weight and how you play. One of the four of us answers, usually the same day, with an honest quote. Nothing to pay to ask.
