Disc Tumbler Locks

A disc tumbler lock is a lock comprising slotted rotary detainer discs. A key specially cut for the lock turns the discs, like a safe’s tumblers, to line up with the slot. This allows the sidebar to fall into the slots and open the lock. The disc tumbler lock mechanism varies from wafer tumbler locks and pin tumbler locks because it doesn’t use springs.

As a result, they are best for places with severe conditions, usually outdoor areas such as railroads and installations at public utilities.

The history of disc tumbler locks 

Finnish scientist Emil Henriksson (1886-1959) invented the disc tumbler lock in 1907. He patented the lock and manufactured it under the Abloy brand. They are used on most Finnish household doors to date.

Design of disc tumbler locks

The classic Abloy design contains a hemicylindrical key with notches and a lock with detainer discs filled with holes varying from an 180⁰ hemi-circle to a 270⁰ ¾ circle. When the key is inserted into the lock and turned 90 degrees, notches, aligned at an angle link themselves to complementary angles in each hole of the disc. Hence, the slot misalignment is “resolved” by rotation to the correct angle.

How do disc tumbler locks work?

For instance, if a hole is 270 degrees, the key will be 180 degrees, and if the hole is 240 degrees, (that’s 270⁰ minus 30⁰), the key will be 150 (180⁰ with a 30⁰ notch). Furthermore, each disc has a notch in its perimeter, a sidebar within an opening in the cylinder lock around the discs. An edge contained inside the casing prevents the cylinder from moving beyond 90 degrees.

When the right key is placed inside the lock and turned, all the discs rotate to align the notches in the perimeter. This drops the sidebar from the cylinder into the groove formed by the notches lined up in the discs. In this position, it prevents the obstruction of the cylinder, allowing it to turn fully and open the lock. However, if the wrong key is inserted into the lock, the notches won’t correspond, and the disc will be rotated at the wrong angle. As a result, the lock cannot be unlocked.

To lock the lock, it is rotated in the opposite direction, sliding the sidebar into the opening of the cylinder. This allows the key’s straight edge to restore the discs to their original scrambled position.

This system makes it easy to build locks that can be unlocked with several different keys. Blank discs with a circular hole are applied, and only notches that match the keys are used in the lock system. This type is mainly used in security doors like the garages in some buildings.

How secure is a disc tumbler? 

A disc tumbler is quite secure and a lot harder to pick than your average lock. Because it doesn’t use springs, it is not as susceptible to rust or easily weakened by damp weather.

They are often marketed as ‘high-security’ locks. You cannot bump a disc tumbler; it is this difficulty that gives it an edge because burglars who have to resort to more sophisticated methods. They can, therefore, be used in cam locks to secure money drawers, or file cabinets, tool boxes and lock boxes

Some cheaper disc tumblers can be opened by torqueing it with a metal device. However, the more expensive ones use hardened metal parts that make this technique impossible.

How much do disc tumbler locks cost?

This will depend on the make and model of the lock. While disc tumbler cam locks ¾ inch, Nickel key costs $10.75, a disc tumbler cam lock Nickel key C415A costs $12.49. Of course, there are more advanced locks, depending on the place to be secured. Note that the cheaper the lock, the more likely it is to be breached.

When it comes to security, avoid scrimping on your expenses. The complexity of locks you buy should be determined by the need for security. Outside doors will naturally require more complicated locks than inside doors.

Contact KC Worthing Locksmiths for reliable locks

When installing new locks, it is advisable to work with professionals. Our locksmiths are accredited by the Worthing police and trained to provide expert guidance on your security issues.

Are you in Worthing? Contact us today:  01903 641 250