Quick Answer: Pool cues use one of five common joint pins — 5/16x14, 5/16x18, 3/8x10, Radial, or Uni-Loc — and the pin is what decides whether a shaft will physically thread onto a given butt, not the brand name on the cue. 5/16x14 is the most widely compatible joint across brands, according to Quarter King Billiards’ 2026 joint guide, while Radial and 3/8x10 look similar but are not interchangeable with each other. If you’re shopping for a shaft-only upgrade or a spare shaft, check the joint pin before checking anything else.
Cue shopping gets confusing fast once you start looking at shaft-only upgrades, because the deciding spec usually isn’t the wood or the wrap — it’s the joint pin threaded into the butt. Two cues can look nearly identical and use completely different joints, and two joints can look nearly identical and still not thread together. Here’s what each type actually is and why it matters.
Pool cue joints, by the numbers:
- 14 threads per inch is the thread count on a 5/16x14 joint, the American production standard used by McDermott, Schon, and older Joss and Meucci cues — and the most widely compatible pin for aftermarket shaft swaps, per Quarter King Billiards’ 2026 guide.
- ~1 full turn is roughly what it takes to seat a Uni-Loc Quick Release shaft, versus about four turns for a standard Uni-Loc joint, according to the same Quarter King Billiards breakdown.
- 10 threads per inch on a 3/8x10 joint — fewer, deeper threads than 5/16x14 — is what produces its noticeably crisper, more direct hit.
The five joints you’ll actually see
| Joint | Spec | Common on | Feel |
|---|---|---|---|
| 5/16x14 | 5/16" pin, 14 threads/in, flat face | McDermott, Schon, older Joss/Meucci | Classic, slightly cushioned, wood-to-wood |
| 5/16x18 | 5/16" pin, 18 threads/in | Some European builds | Tighter, more immediate contact |
| 3/8x10 | 3/8" pin, 10 threads/in | Many custom/semi-custom American cues | Crisper, sharper feedback than 5/16x14 |
| Radial | Radial thread profile, not a standard V-thread | Predator and licensed shaft makers | Firm but smooth, low shock, highly repeatable |
| Uni-Loc | Short pin, deep thread; Quick Release ~1 turn | Modern Predator (P3, BLAK, Throne) | Firm, quiet, low vibration; between Radial and 3/8x10 |
Two pins that look alike on a quick glance — 3/8x10 and Radial being the classic mix-up — are not interchangeable, because the thread geometry is different even when the pin diameter is close. If you’re buying a shaft to fit an existing butt, match the joint spec exactly rather than eyeballing the pin.
Why the joint changes how a cue plays
- Coarser, flatter threads (5/16x14) cushion the hit. Fewer contact points between pin and collar spread the shock out, which is why 5/16x14 gets described as a classic, wood-to-wood feel rather than a sharp one.
- Finer or deeper threads (3/8x10, 5/16x18) sharpen it. Less give in the connection means more of the impact reaches your hand directly, which reads as a crisper, more immediate hit.
- Radial and Uni-Loc are built for consistency, not just feel. Predator engineered both to minimize the joint as a variable shot-to-shot, which is why players chasing repeatable low-deflection performance tend to land on one of the two rather than a traditional flat-faced joint.
Pool Cue Joint Protector Caps
- Screws over the exposed joint pin during transport or storage.
- Prevents grit and dings that make a shaft harder to thread on cleanly.
- Cheap insurance for any joint type — 5/16x14, 3/8x10, Radial, or Uni-Loc.
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How to identify your cue’s joint before you buy a shaft
- Look at the exposed pin when the cue is unscrewed. Note the diameter and whether the threads look coarse and few (3/8x10-style) or fine and many (5/16x14/18-style).
- Check the brand and model against known joint standards. McDermott and Schon builds are commonly 5/16x14; modern Predator butts are typically Radial or Uni-Loc — but always verify against the manufacturer’s spec rather than assuming by brand alone.
- Never assume Radial and 3/8x10 are interchangeable just because they look similar. Confirm the exact joint name before ordering a shaft-only upgrade.
- When in doubt, ask the seller or manufacturer directly. A five-minute question beats returning a shaft that won’t thread on.
- If you want to skip the guesswork entirely, buy shaft and butt as a matched set. A complete cue removes the compatibility question altogether.
Already decided you want a low-deflection carbon shaft? Our best carbon fiber cue guide covers joint compatibility on shaft-only upgrades like Predator’s REVO line. Building a dedicated break cue instead? Our best break cue roundup breaks down Uni-Loc and Radial break-specific builds, and our pool cue weight guide covers the other big spec question — how heavy that cue should actually be.
The bottom line
The joint pin, not the brand name, decides whether a shaft will fit a given butt. 5/16x14 is the safest bet for wide aftermarket compatibility, 3/8x10 and Radial trade a crisper or more consistent hit for narrower compatibility, and Uni-Loc trades some of that universality for quick-release convenience. Match the exact spec before buying a shaft alone, and when in doubt, buy a complete cue instead.