A customer recently asked us if a padlock could be made more secure by adding nuts or washers to the shackle, effectively making a closed shackle padlock.

The answers is Yes and No. As seen here we added two stainless nuts to a marine stainless padlock to protect an outboard engine. It clearly does protect the shackle more, especially on a stainless lock which can be cut relatively easily.

Now here is the caveat. It will protect from saws and disc cutters since the shackle is both protected and the nuts will spin when a cut is attempted! Great huh! However, we’re concerned about the use of bolt cutters in this arrangement. The bolt cutters would get in-between the nuts and create a hug amount of leverage. That leverage, as the nuts are forced apart, would put pressure on the mechanism of the lock. In this case the ABUS Submariner has a quality double ball baring mechanism so it is less of an issue. However, on a lesser lock, it may cause the shackle to pop-open as the locking bar is snapped.

Conclusion: Yes this adaptation it will make the lock more secure to cutting attacks but maybe not from bolt cutters. If the lock has a ball baring mechanism then I would say, yes, go ahead. If not then no don’t bother. You can tell if it is BB locking by opening the lock and looking down the hole where the shackle was. If there is a round ball baring then you are good to go. If you see a triangular shaped bar which is spring loaded, then leave the lock alone.