This is a working combination padlock design that can be used in place of a standard Master Lock on a locker or whatever. It's relatively strong, but it is plastic it's, so not for high security.

UPDATE 8/22/2024:

• Fixed the body models adding more clearance around the detents and springs. Use Body_FIXED.STL. This should resolve the printing issues many people are having.

• Added an option to print the springs separately if you prefer. The springs work quite well this way and should be easier to print successfully. Use Body_noSprings.STL and Spring.STL. Updated instructions are below.

Features:

• Configurable combination: up to 10,000 possible combinations
• Selectable security options: 3 or 4 tumblers with 6 or 10 digit numbers
• Spring loaded detent feature on tumblers for precise positioning and satisfyingly tactile feedback
• Similar dimensions to classic rotary Master Lock for compatibility with most lockers and other latches
• Strong lock body and shackle that resists forcing open
• Normal or long shackle options for securing larger latches
• SolidWorks files for your own customization

v2 Improvements:

• Print-in-place springs for detent works far better than old design which would break after a while
• Option for 3 or 4 tumbler lock and 6 or 10 digit tumblers
• Threaded cap eliminates glue and allows for easier changing of combination.
• Taller wall next to shackle latch better resists forcing open of the lock
• Flipped tumbler position for easier right-handed operation
• Tumblers can now be printed without supports
• Various changes to make printing easier and cleaner

Combination mechanism inspired by thingiverse.com/thing:409462 by BLed.

Files to Print

The parts are all interchangeable for many different configurations. Here are some examples of STL files to select:

Example 1: 3 tumbler lock with 6 digits and long shackle, combo 123

• PadlockV2_Body3x_FIXED.STL
• PadlockV2_Shackle3xLong.STL
• PadlockV2Tumbler6x1.STL
• PadlockV2Tumbler6x2.STL
• PadlockV2Tumbler6x3.STL
• PadlockV2_Cap.STL
• PadlockV2_Spacer.STL

Example 2: 4 tumbler lock with 10 digits and short shackle, combo 1982, with springs printed separately

• PadlockV2_Body4x_NoSprings.STL
• PadlockV2_Springs.STL (print 4 of these)
• PadlockV2_Shackle4x.STL
• PadlockV2Tumbler10x1.STL
• PadlockV2Tumbler10x9.STL
• PadlockV2Tumbler10x8.STL
• PadlockV2Tumbler10x2.STL
• PadlockV2_Cap.STL
• PadlockV2_Spacer.STL