Toy OTF Switchblade (Double Action)

Toy OTF Switchblade (Double Action)

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P1S
P1P
X1
X1 Carbon
X1E
A1

0.12mm layer, 3 walls, 30% infill
0.12mm layer, 3 walls, 30% infill
Designer
7.3 h
2 plates
3.2(6)

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Released

Description

CHECK OUT THE IMPROVED VERSION HERE

 

This is a toy Automatic OTF Knife I designed. What makes this design different from a typical switchblade is that it not only ejects the blade when the switch is pushed forward but retracts when the switch is pushed backwards. This means it does not need to be manual reset like a classic switchblade. It also means its very fun to play with.

 

Check out my new fidget spinner and print in place bearing here.

 

You can find my other toy knife designs here.

 

You can obtain a commercial license to sell prints of this here.

Print Settings

Resolution:

0.1 mm

Infill: 

30%

Notes:

 A brim is also recommended if you have problems with bed adhesion.

 

Support Removal and Assembly Instructions

The first step after printing is removing supports. There are supports on the handles, carriage, and blade. You can use the assemble animation and photos below as a reference of what it should look like after supports have been removed.

A video showing how to assemble the design is located below.

 

In addition to the 3D-printed parts this design requires additional hardware. It requires 3 screws, 2 springs, and 2 to 4 rubber bands. I have included the links to the exact parts required but they come in large packs that may not be convenient if you are making only one knife. A more affordable option would be going to a hardware store and finding substituents. You can also take screws and springs from a Nerf gun.

When assembling first check that the carriage (the part with the blade inside of it) slides freely inside the handles. Then check that the blade slides freely inside the carriage. If anything does not slide smoothly sand down contact surfaces. For the design to work properly the latch springs and rubber band tension must be just right. This can be calibrated my changing the number and type of rubber bands. For the springs I have I like to use two strong rubber bands (one on each side) and two weak rubber bands (one on each side). The design also works with asymmetric rubber band arrangements. Information about hardware specifications can be found below.

 

Springs - https://www.mcmaster.com/catalog/129/1492/9657K614

Screws - https://www.mcmaster.com/catalog/129/3372/90385A317

Strong Rubber bands - https://www.amazon.com/dp/B093Q2M536?psc=1&ref=ppx_yo2ov_dt_b_product_details

Weak Rubber bands - https://www.amazon.com/dp/B008X0A1NA?psc=1&ref=ppx_yo2ov_dt_b_product_details

 

 

This video shows what each part should look after the supports have been removed. It also shows how to assemble them.

 

Uncut video of me assembling and troubleshooting.

 

Comment & Rating (11)

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I love dual-action OTF blades and this is easily my favourite looking design for one that's 3D printable. But, unfortunately, I could not get mine to work. There is just simply way to much resistance on all the moving parts. I tried sanding and thoroughly lubricating the internals which helped slightly. I also tried adding more rubber bands in an attempt to shoot the blade out with more force which did actually work for a little while to some extent until one of the rubber band hooks broke. I'm not exactly sure what went wrong with mine or what would help with the issue. Maybe looser tolerances? Maybe minimizing contact between moving parts? I printed using your pre-set settings on a P1S with Bambu PLA.
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I'm glad you like my design and I appreciate the detail you have included in your comment. Here are a couple things you could try. - If you haven't already, watch my trouble shooting video. It is a good example of how I sand problematic areas. - Try moving the parts by hand and feeling for points of friction. Sometimes if you manually push the blade through the carriage you can feel where an imperfection is and sand it down. This processes may take some time but eventually enough sanding should allow the parts to move smoothly - A brute force method is to add more rubber bands again but print the rubber band hooks out of a stronger filament. Printing them with something like Bambu Labs tough PLA can make them significantly stronger compared to regular PLA. - It is unlikely but possible that your fulfillment has absorbed moisture. Try removing the moisture or using a new role of filament. - Be careful not to use too much lubricant. To much lubricant can gunk up the mechanism. Hopefully one of these tricks helps you. If you need more help just comment again.
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Replying to @OwenTF :
With a lot more sanding, silicone spray as a lubricant-substitute, and a re-print of both rubber band hooks, this time with a -0.1 contour compensation to give just a little bit more clearance, I got it to work! It also seems to be getting better the more I use it as the internals are continuing to slowly sand themselves down. Now that it's all built and working my only suggestion would be an alternative to using screws in the design. I didn't have any screws laying around that fit the slots particularly well and, as a result, aren't completely flush and stick out quite a bit. Maybe something like internal holes for raw filament to fit in and hold it together? I've seen it used on a few other designs and it seemed to work well for those, but that's just an idea. Thank you for the help and, again, fantastic design! Really happy with how it turned out.
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Replying to @Spaghetti_Sauce :
I'm glad it worked out and I appreciate the feedback.
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why do we have to pay for the other that’s dumb it looks cool and all but really
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0.12mm layer, 3 walls, 30% infill
ended up working flawlessly with very little post processing
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0.12mm layer, 3 walls, 30% infill
It broke while printing
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0.12mm layer, 3 walls, 30% infill
Support Issue:The model is not positioned in the best way and with vibrations and anything else it is difficult to bring the silk of the shell to the bottom and we will be for the rest beautiful model !!
Other Issues
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0.12mm layer, 3 walls, 30% infill
Bed Adhesion Issue
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0.12mm layer, 3 walls, 30% infill
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0.12mm layer, 3 walls, 30% infill
(Edited)
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