Hello everyone, I wanted to create something fun and scary for the Halloween season, so I made a working prop knife using 123D Design. 123D Design is new software to me, but its absolutely amazing. I also am including the 123dx file so you can 3D print it for yourself!

If you have any questions please feel free to message me anytime.

Thanks for following, Joe

Step 1: Building a Base

 Using 123D design, I found it makes it really easy if you start your project off with a solid sketched base. Something else that might helpful is to draw a rough sketch, with measurements, of your project on paper first.
   I started my project off building the sketched base of the knife handle, and the area where the knife blade will be. When I built the base I just entered the pre-measured dimensions, which made it very easy to create.

Step 2: Creating the Handle

   In this step, I took the sketched base that I created for the handle, and extruded a solid up from it. 123D Design makes it really easy to create, move, and manipulate objects. For example I took the extruded oval and used 4 spheres to cut out finger grips on the handle using the combine option (subtract). 
   Now there are 4 dimples in the handle, but they are rough. In this case you can smooth edges out with the fillet tool, I fillet mine at .384 degrees.

Step 3: Adding a Base to the Handle

   We now need to create a sketched base to the handle, extruded it up, and fillet the edges ( the fillet option is under the modify button ). Another thing I found that made my work easier was the hide option. You can hide sketches or solids to clear them out of your way to allow you to see what you are currently working on.

Step 4: Adding Slides to Lock the Base to the Handle

   As you can see, creating a base sketch and extruding is pretty much all it is. In this next step I created a sketched base for slides to connect the base to the handle. This will hold the knife blade and spring within the handle.

( To remove a shape out of a solid, create a base and extrude into the object, but use the cut option. )

Step 5: Adding a Top to the Handle

   Now to cap off our creation.... Sketch a base,extrude, fillet, and this time we are going to use the combine option and join the top with the handle physically.

Step 6: Extruding a Spring Channel in the Handle

Extrude a spring channel in the handle using a circle sketched base.

Step 7: Creating the Blade

   Here I extruded the blade up , but I didn't have a tip to the blade. No worries though... I created a cone and overlapped it over the sketch for the blade and extruded/ cut around it. At this point I have something that resembles a blade tip.
Now to make it look better... Muhaha!
 Instead of using fillet, use chamfer under modify this time. This creates a sharp edge instead of a rounding edge that the filleting does.
 Once my tip is created, I joined it with the combine option making it one solid blade.

Step 8: Creating and Adding a Stop to the Blade

   Here is the step that changes a ballistic knife into a prop knife; adding the stop, unless you want to shoot people with knife blades. Make sure to join it with the combine option.

Step 9: Unleash the Fury... Muhaha!

   Thank you so much for following and commenting. I have always been a huge fan of instructables.com, but now I really want to get involved and share my ideas. So expect more great things and have a safe and happy Halloween.

Very cool
Thank you so much for the comment. Comments and followers are inspiring.
no prob man!
Does the spring print too or do u have to buy a metal one
Great question, and thank you for bringing it up. The spring does not exist in the downloadable 123DX file, you can always fabricate or purchase a spring for a few dollars.

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