Tubular Locks Explained: How They Work, Where You Find Them, and How to Pick Them

Tubular locks arrange their pins in a ring around a central post and read them with a cylindrical key. They shrug off ordinary picks completely, but a tool built to match the geometry opens (and decodes) one in seconds. Here is how the mechanism works, where you will find one, and how the dedicated tubular pick changes the game.

What is a tubular lock?

A tubular lock is a pin tumbler in the round. Instead of pins arranged in a line above the keyway, a tubular lock arranges 7 or 8 pin stacks in a circle around a central post. The key is cylindrical with notches cut around its circumference, one for each pin. When the key is inserted and rotated, every pin must reach its shear point at the same time for the plug to turn.

Visually, the giveaway is the round keyway with a center post and a ring of small openings around it. The key itself looks like a short metal tube with notched cuts around the rim. Once you have seen one, every vending machine, coin-op laundry, and bike lock with this profile becomes recognizable at a glance.

How tubular locks work

Mechanically, every pin stack works exactly like a standard pin tumbler. A spring-loaded driver pin pushes a key pin down into the plug; the key pin must be lifted to align the gap between the two with the shear line; the plug can then rotate. The only difference is geometry: instead of lifting pins from below into a stack above, the key pushes pins outward (or inward, depending on the design) from the center post.

Two consequences follow from the circular layout:

• All pins must be solved together. There is no straightforward way to apply tension and pick one pin at a time, the way you would with a standard pin tumbler. Single-pin picking is impractical without a tool that grips the whole ring.
• The geometry is predictable. The pin spacing and pin count are fixed within each tubular standard, so a single tool can address every lock built to that standard. This is why a dedicated tubular pick opens the entire category, not just one keyway.

Where you will find tubular locks

Tubular locks turn up in low-to-medium security applications where their distinctive footprint signals "I am a different kind of lock":

• Vending machines, coin-operated washing machines, and ATM service panels.
• Bike locks (most U-locks and chain locks in the 1990s and 2000s used tubular cores; the better ones moved to disc detainer mechanisms after the famous Kryptonite-bic-pen incident).
• Gun cases and small commercial safes.
• Alarm panels, sprinkler valves, and elevator control panels.
• Display cabinets, jewelry cases, and trophy cases in retail.
• Industrial cam locks on electrical and utility cabinets.

Most tubular locks you will encounter in the wild are 7-pin, which is the legacy standard for vending and bike applications. Higher-security versions move to 8 or 10 pins, sometimes with anti-pick features such as false notches in the pin stacks.

How secure are tubular locks?

Tubular locks sit in the middle of the security spectrum. They are far harder than wafer locks but considerably easier than dimple or disc detainer locks because the geometry is so predictable.

• Pin count. 7-pin tubular locks have the smallest theoretical key space and are the easiest to pick. 8-pin and 10-pin versions are noticeably harder, and 10-pin tubular locks with anti-pick pins begin to compete with mid-tier pin tumblers.
• Anti-pick features. Better tubular cores add false notches and spool-style pins that resist the rocking motion of a basic tubular pick.
• Single tool defeats the family. The biggest weakness is structural: a $90 tool opens every standard 7-pin tubular lock on earth. There is no per-keyway diversity to fall back on.

For the price points where tubular locks live, this is fine. Vending machines and bike locks are not trying to defeat a determined attacker, just a casual one. For anything you actually want to protect, a tubular lock is the wrong choice.

How to pick a tubular lock

One technique dominates: a dedicated tubular lock pick with the right pin count. Every other approach is either slower, less reliable, or both.

1. Dedicated tubular pick + decoder

A tubular pick has the same cylindrical body as the matching key, with adjustable pin-position feelers in place of the cuts. You insert the pick into the lock, apply rotational tension on the body, and rock the pick back and forth. Each feeler finds its pin's shear point and locks in. After a few seconds of rocking, every pin is at its shear point and the plug rotates. Pull the pick out, and the feelers retain the cut depths, so you can read the key bitting directly off the tool. With a matching key blank and a file or duplicator, you can cut a working key.

Time to open a 7-pin lock with the right tool, after a small amount of practice: 5 to 60 seconds.

2. The Bic pen technique (legacy, mostly defunct)

Until around 2004, many Kryptonite bike U-locks used a 7-pin tubular core that could be opened with the cut-off barrel of a Bic ballpoint pen. The pen body fit the keyway, and rotating it under tension defeated the mechanism. Kryptonite redesigned every tubular U-lock model after the technique went viral in 2004; modern bike locks that still use tubular cores have anti-pick features that defeat the pen attack. The technique survives only on the cheapest legacy bike locks and on old vending machines.

3. Impressioning

For locksmiths working in commercial environments where a key needs to be cut and the lock kept intact, impressioning a tubular blank by hand and filing the cuts works but is slow. A tubular pick with a decoder makes this obsolete in most cases.

Tubular vs pin tumbler at a glance

Both mechanisms read the key with pins meeting a shear line. The geometry, pin layout, and tool requirements put them at very different places on the security and tooling curve.

A 7-pin tubular lock is the most common variant; 8-pin and 10-pin versions are harder to pick but still fall to the right tool.