Master Lock 1500

LockReviewer’s Take: Low price, low security. A fine option if you have nothing worth stealing. Let’s face it, this lock is not going anywhere so long as students continue to grab them out of a bin at the bookstore while buying their books.

Master Lock says:

The Master Lock No. 1500 3-digit combination padlock has many enhanced security features like the exclusive BlockGuard® Anti-Shim technology, hardened steel shackle and double-reinforced stainless steel casing. Designed to fit lockers with a padlock eye of at least 5/16in (8mm) diameter, these locks provide multiple customization options to fit your needs.

  • Patented BlockGuard® Anti-Shim Technology withstands attempts to violate the latch mechanism
  • 1-7/8in (48mm) wide double-reinforced stainless steel body
  • 3/4in (19mm) tall, hardened steel shackle for extra cut resistance
  • Easy 3-number dialing with automatic scrambling feature to prevent reopening of lock

The Master Lock 1500 is perhaps the most common combination lock in use across schools and gyms in North America; however, it is also subject to easy opening even to those not privy to your combination. As you probably have guessed, I am going to focus pretty much specifically on the bad here. I will say a few positive things before getting into the bad. In my opinion the 1500 is sturdy and opens easily even after years of abuse. The way that most would-be thieves get into these locks is by watching users close them and simply walk away, effectively leaving the lock still open. An automatic scrambling feature prevents someone from reopening a forgetful user’s lock after he or she walks away.

On to the bad. This combo lock is susceptible to two common attacks. The first is shimming. Yes, the “BlockGuard Anti-Shim” technology is supposed to prevent shimming. The fact of the matter is that it does not prevent shimming, but it will provide an increased challenge. Below you can see that the old soda can trick still works on these “shim proof” models.

As I’m sure every deviant knows by middle school, there are very simple tricks into figuring out the combination of these locks with just a little bit of shackle tension. The fastest method I have located can be seen below. Watch just how easy the 1500 flies open with minimal practice. Would you even notice a thief doing this?

Finally, the most obvious way to get through the 1500 is by bolt cutting. How many times did you see a janitor in middle school clip through the shackle on one of these like butter? It was at least once a week for me. There are so many alternatives out there to this lock. For a better price and without the hassle of a combo lock, try the Abus 64/40. If you want something new and much more secure (but with my caution regarding reliability) try the iD1500.

Verdict: The 1500 has far too many vulnerabilities to make it feasible even for using at school given the fact that it can be easily opened by a thief without raising any suspicion. Buy anything else.

Master Lock 1500






Bypass Rating




Build Quality



  • Classic
  • Somewhat Affordable


  • Subject to Bypassing
  • Unsecure
  • Wide Knowledge of Vulnerabilities

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