This is a functional, toy/prop version of the ballistic knife from the popular video game Call of Duty.

The main parts in the 3mf file (frame, firing mech, end cap and spring cap) should be printed in a tough material like PETG to be able to withstand the force of the springs. The attachments should NOT be printed out of a hard material so they don't break on impact or cause injury or harm; they should be printed out of a flexible material like TPU.

NOTE: There is no print profile for the attachments

ASSEMBLY:

The only bought part of this are the springs which can be obtained from the link below. To achieve maximum power two of the springs should be weaved together as shown in one of the pictures. The springs should then be attached to the 3D printed parts is using hot glue or any alternative adhesive (I know its messy but it works). Finally the spring assembly slides into the main body and can be secured with a thin adhesive like super glue.

Springs:

https://www.amazon.co.uk/gp/product/B09136PCTS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1