Hello there?i am engineer and product design,i am very interested with your project,i can help you for development your knife with sliding mechanis,i am can send format file you needs,as STEP,IGES,DXF,DWG,STL,and etc,please share detail your file and requirement,i am can start work right now,i am have 13 years in manufacture and make design 3d modelling and 2d drawing,i'll send good result and hight quality,i hope we can work togheter and i am very happy if can help you,thanks Dedy.e