3D-Printed Combination Lock

by ROBK636, published

3D-Printed Combination Lock by ROBK636 Mar 24, 2010

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This was for a final project for my 3D modeling class. I went with a Combo lock. It was done to show how a basic combo lock works. Total size is 4 inches wide. 3.5 front to back and 2.5 tall and is made of 10 parts.

I was going to do a Anniversary release of the files, but I am releasing it sooner because I get asked every once in a while about the .STL files or the Inventor.IPT files so here you go. Enjoy.

Inventor IPT files are for Inventor 2009


Print one of each part. Print 3 of the spacers.

SLT files can be downloaded separately, or a zip file that has all of the STL files in it.

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Some suggestions on my build using Cura as slicer. Almost all the parts are assumed inches so they are very tiny in Cura. I applied a scale of 25.4 to these parts. For Rotor 3, I also added an extra 25% to Z so the scale factor for that part was X,Y,Z=25.4,25.4,32. The spacers were a different story. They were huge. For them I found a scale factor of .0254 worked well. I used supports for all parts except the two dials and spacers. Finally Rotor 2 can go in two different ways (forward or backward). One way makes the combination too weird with the second and third number practically the same. So flip Rotor 2 around if you have that issue.

I used a wood filament and the pins and rods were prone to breaking so careful in working around them. Bumping the temp up a little helped the layer adhesion.

Did a build of this (also followed soapy's advice and bumped the rear rotor/axle model by 25% in the Z axis). Went together smoothly! Built with PLA on a Flashforge Dreamer.

In the flashforge printing software, it assumed the units were MM, but it has a MM->inches converter in the scale functionality. Due to the pins on the middle rotor, I had to build that part with a bunch of support material (a little annoying).

Has anyone remixed this and altered the pin locations at all? Would love for this model to be parameterized so I can specify the combination series I'd like it to encode. Or maybe have the rotors have a bunch of holes and the pins can be inserted where preferred?

Just built this one following soapy's advice, and it worked out perfect!

This model doesn't actually work as uploaded.

Either you can spend ages messing around trying to modify the parts once printed, or, you can simply stretch the spindle
amp; rear disc part by ~25% in the Z axis (to lengthen the spindle) and it should go together far more easily.

awesome model, can't wait to print this. quick question, are the stl files orientated in the correct direction for printing? the base looks like it will need a lot of support

Can you Please post the Iam file so I can play with in inventor 7

I uploaded the .iam file.

seen this in real life and its gorgeous.

I'm realy looking forward to make one of these!

This is just downright awesome..! great model. Now Im really wanting support material for my MakerBot.!

I'm not 100% sure because I'm still waiting for my makerbot to get shipped, but looking at the individual components, it looks like this can be printed without support material. You might have to slightly modify the model so the base component can be printed in two parts so they can both be printed flat.

The lock arm and rotor2 definitely aren't printable without support material. Rotor 3 probably isn't and rotor 1 looks a little iffy.

The units also seem to be in inches instead of mm.. :\