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Trick Puzzle Bolt Safe

by robrook May 13, 2014
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I printed this and mine had a $10.00 bill inside.
I needed exact change for the bus so had to print 4 of these for the $40.00 Uber charged.

I had some issues importing the files as others have mentioned. The issue I found is the 2 Nuts are in mm and the Bolt is in Inches. Couldnt slice it on 1 print with Replier, however I was able to make it work in Simplify3D

It's really a mess. The US Dollar Note is not printed ...... :)

Each of the individual files came up super small (real small!) in my slicer software, and I could not scale them bigger consistently across the 3 parts... Nice idea.

Same problem. Something is odd with the size.

can not get ether end on :( but good idea

can not get ether end on :( but good idea

I had troubles getting the nut to screw on the thread (not the cap end).

Very nice idea for a print :) I just printed it, however I think it is a shame that you are able to see the thread comming out of the "head nut". It would even nicer if the bolt were made to fit into the "head not" so no thread were vissible (shrink the last part of the bolt so it can slide into the "head nut").
As is the puzzle is very easy to solve ;)

fyi, if you try to slice and it looks too small, note STL is in inches, so if you slicer is in mm, just scale it up by 2540%.

Thanks for being as interested in this creation as you are. Some of you folks are much more in tune to 3D printing specifics than I am. For your information though, I make this on a CUBE 3D printer (by #D Systems), their second model. I did NOT have to use anything to brace or support it during printing as the glue I have to use holds it firmly. However, if you are having trouble keeping it stable I have used modelling clay to stabilize prints before. You have to be very careful applying it. Obviously you have to wait until the print is 1/2" or so in height. Then VERY GENTLY put some wads of pliable modelling clay around the base of the bolt. This will hold it stable. I hope this helps. I had never really thought about it before, but I can see why and how using different brands of printers can create subtle problems that I did not have. For instance, on mine I do not have any precise setting for the clearance between the print head and the printing surface: I have to set it by 'feel'! But it is tight, a thin sheet of paper will barely slide in the gap.Good luck. Rob

Thank you Rob for your Design. I like the idea.
But I had several problems that I would like to point out.

  1. As others pointed out before, the three files were indeed scaled for an inch printer. Therefor scaling by 2540 % was nessesary.
  2. The threads on the long end of the bold seem to change diameter. I coult not see this in my splicer (Cura) and dont know how this error occured or where it originated (Did I mess something up or is the file faulty
  3. The threads on either end dont run out smoothly but instead have some incontinuity. This is visible in splicer as well. Some small part of the print has to be cut or sanded away to get the nut on the threads.
  4. There is an end stop from the short thread to the smooth surface that is supposed to give the cap a point to be locked. Basicaly elegant idea, but sadly the same geometry should be provided in the cap. As this is not the case, the end stop on the thread is not concealed by the bolt all the way and the "trick" is easily detectable.
  5. Both the bolt and the cap dont run parallel to the bolt. They stand in an angle of about 5° which makes the part look crooked. I can not determine the cause.

Thank you Rob. I enjoy good ideas and this is one. Thats why I want to give you this constructive criticism and I hope you know I mean well!

What kind of support did you use (if any)? As my first attempt reached the smooth area of the bolt, it became unstable and subsequent layers were not aligned. Did you brace it? or maybe slow way down? Figured I get any tips you have before retrying. Great project. II love it...now if I can just reproduce it :-)

What kind of printer do you have? It may depend on how your printer does x and y movement. For instance, my Solidoodle 2 has a bed that only moves along the z axis. if you have something like a Prusa i3, it might move from side to side enough to shift the print as momentum gets a hold of the tall unstable print. If that's the case, I'd say slow it down.
I've tried to print this once before and I'm trying again just now. I printed it at 20x because I thought the original model was tiny. Even while being bigger I dropped a loop or two on every thread so it was impossible to clean up. Now i'm printing at 40x and it has dropped only one loop and it looks easy enough to clean up. I'm sure my extrusion rate is too high and I'll tune that up after I print this screw. This is a great test to prove that you need to get that stuff locked in.
Another problem might be that I'm trying to print at .3mm layer height. That's not uncommon but for the original model and how fine it is in general, it might work better at .1 if you can get your printer to do it. Might be my next hurdle. I'll be sure to post a make as soon as I get a working one.