This is the first working 3D printed shredder for kitchen food waste. Perfect to make compost. http://youtu.be/1erMSmSHajU Printed from PLA. How to assembly : http://issuu.com/marcusthymark/docs/boom_assembly/0 First version breaks at 25Nm torque, second version at 50 Nm torque. The version uploaded here is number 3 and hold up to 74 Nm torque. ( Then break ) Shredding some chicken bones : http://youtu.be/A4rg--VEXVM Update done 14.July 2014 ( read comments. ) How to assemble vid : http://youtu.be/j4a-f51Ypc0 Changed bioshredder spacer STl for bioshredder spacer 2 STL. ( only metric ) This is metric system version in mm ( for inch scroll down ) For the shaft you will need 2x square tube 30x30x2mm long 122mm All other parts are : 4x screw M10x30 8x screw M8x30mm 12x screw M5x20mm 4x ball bearings ( SKF 6006 ZZ or 2RS ) To print are : 3x cup.stl ( 0,3 layer, 0,3 infill ) 2x spur gear.stl ( 0,25 layer, 0,4 infill ) 2x spur gear 15mm.stl ( 0,25 layer, 0,4 infill ) 2x printed bearing holder.stl ( 0,25 layer, 0,4 infill ) 2x printed bearing holder thin.stl ( 0,25 layer, 0,4 infill ) 2x side print.stl ( 0,3 layer, 0,3 infill ) 1x for shaft long.stl ( 0,2 layer, 1 infill ) ----!!!! very important !!!!--- 2x for shaft1 .stl ( 0,3 layer, 0,4 infill ) 1x for shaft1+5 .stl ( 0,3 layer, 0,4 infill ) 8x bioshredder spacer 2.stl ( 0,3 layer, 0,3 infill ) 8x bioshredder.stl ( 0,3 layer, 0,4 infill ) 4x print st.stl ( 0,3 layer, 0,3 infill ) --------------Parts for metric hand crank---------------- 1x threaded rod M10 2x washers for M10 screws 1x dom.stl 1x print handle.stl 3x nut 17.stl ....................................................................................................... This is imperial version in INCH For the shaft you will need 2x Square Tube 1-1/4" x 1-1/4" Thickness 0.065 Inches, long 4.8 inch All other parts are : 4x screw 3/8 long 1-1/4 8x screw 5/16 long 1-1/4 12x screw 3/16 long 1/2 4x ball bearings ( R20 ZZ or 2RS ) To print are : ( layer hight in mm and infil in % 1= 100% ) 3x cup.stl ( 0,3 layer, 0,3 infill ) 2x spur gear INCH.stl ( 0,25 layer, 0,4 infill ) 2x spur gear 15mm INCH.stl ( 0,25 layer, 0,4 infill ) 2x printed bearing holder INCH.stl ( 0,25 layer, 0,4 infill ) 2x printed bearing holder thin.stl ( 0,25 layer, 0,4 infill ) 2x side print.stl ( 0,3 layer, 0,3 infill ) 1x for shaft long INCH.stl ( 0,2 layer, 1 infill ) ----!!!! very important !!!!--- 2x for shaft1 INCH .stl ( 0,3 layer, 0,4 infill ) 1x for shaft1+5 INCH .stl ( 0,3 layer, 0,4 infill ) 8x bioshredder spacer INCH.stl ( 0,3 layer, 0,3 infill ) 8x bioshredder INCH.stl ( 0,3 layer, 0,4 infill ) 4x print st INCH.stl ( 0,3 layer, 0,3 infill ) --------------Parts for Inch hand crank---------------- 1x threaded rod 3/8 2x washers for 3/8 screws 1x dom INCH.stl 1x print handle.stl 3x nut INCH.stl