Padlock shackle reverse engineering


I am trying to reverse engineer Abloy PL350 padlock shackle and I run out of ideas how to make it perfect. I know the dimensions of the shackle and I can measure anything from existing one with caliper, but I don’t know how to make the arc for the sweep tool symmetrical. I’ve already tried to import image of it and model the arc from that with spline tool. I’ve also tried to use document scanner instead of iphone to produce better image, but both methods are inaccurate in my opinion. At very least it would be nice to get one half of it in exact measures so I could mirror the other half then, since trying to get both halves of it symmetrical with spline tool is mission impossible if you are not able to use “Snap to” options.

The tolerances are going to be very tight around the shackle so closer the better. There is going to be lid over the whole lock body to protect it from cutting. And the whole design is going to be cut to its shape with laser so getting measures right in the first place will be big plus since the material will be chosen to be as cut resistant as possible.

Just to let you guys know that a thief broke into my warehouse lately and now the door is going to be over engineered as fuck. So next time its easier to blow up a hole in the wall than using the door without a key :grin: I am not a engineer (yet), but I find these kind of things interesting as a hobbyist. And even though my insurance covered all the losses I like to give my best to the next thief who tries to steal my property :upside_down_face:

Never mind I just figured it out I think. I lofted it out of thin air :smiley: Now its measures match as much I can measure them with caliper and the shackle is symmetrical on both sides. The arc is looking to be off maybe a notch, but I believe this will be in tolerances to fit in.

Hi, it is great to see that you have found a solution using the Loft tool.
I guess the original shape is bent around a specific radius, so the sweep tool may result in a much accurate result :slight_smile:

On the other hand, if you wish to make a spline symmetrical to any reference, try to apply the symmetry constraint to the control points, instead of the spline itself :wink:

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We charge “double” for answering your own questions and posting solutions in this forum. You’ve been warned! :roll_eyes:

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I am sorry about this. I knew the original post was kind of useless when I figured out one way to get some where close to what I was looking for. But like KPeter_Shapr3D shown us that was still helpful even tho I find one way to do it too. Most likely going to try that one too to see if it gives better results than lofting does. And I had somehow a feeling that the lofting is not the “right” way to do it this time, but it gave decent results so I thought why not.

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It’ll serve as a tutorial/inspiration if one bothers to search a bit. :+1:

Here is yet another way to create that shackle. You can use a partial Revolve.


Very helpful and easy way to do it also. I just had the wrong mindset for this. Now when I think about it that way its so obvious that of course the shackle is part of the full circle and then just cut from the middle and “joined” with straight legs. Although I am not familiar with the Revolve at all so again one more tool to add into my tool box. There is so many ways how you can make these things that it is sometimes overwhelming what tools I should use. Also I’ve find out that reverse engineering is pain in the ass to kind of start this hobby with.

You can mix and match extrudes and revolves.