Dahle 35314 Helical Reduction Gear

Dahle 35314 Paper shredder stopped working with the BIN OPEN light illuminated. Disassembled to find the helical reduction gear was missing teeth down one side.  Contacted the manufacturer and they are unable to provide individual gears at this time. The only other option was to replace the entire shredding head ( basically buy a new shredder ). 

The original part was likely ABS with Fiberglass with a spur gear molded into the helical gear and used two very thin ( maybe 0.10mm) shim washers on each end of the spindle. 

Replacement part is printed in Fiberon ( PA6CF20 ). Instead of molding the spur gear ( not possible with an FDM printer anyway ) I simply created a ring gear for the inside that matched the teeth of the molded part.  Where the original part was molded around a smaller gear, I decided instead to back the helical gear with a thrust bearing as it should have been designed in the first place to better handle the axial load.  The parts were designed as two separate gears and combined into this STL. 

When pressing the inner gear through the helical gear, the thrust bearing should recess 3 mm, leaving only 1mm ( the outside washer ) sticking out. The outside edge of the thrust bearing recessed into the helical gear should have a 0.5mm gap as the inside diameter of that hole is 20mm with a 19mm bearing.  i.e.) the middle of that thrust bearing should spin freely, without friction on the outside edge, but it should be tight upon installation ( gear should not slide across the spindle ).   The shim washers are thin enough I just left them installed. 

Installed part was annealed for 8 hours at 100C.  So far I have 8 hours on the new part with flawless performance.  

To reset the bin open light, I powered the unit on, then held down the forward button for 5 seconds ( yes, it has to be assembled with the bin installed ).  

Filament: Polymaker Fiberon PA6CF

Thrust bearing: AXK0619+2AS ( 6 mm bore, 19mm diameter, 4mm thick ) 

Gear Generator settings: 

  Inside Gear ( Ring Gear )

    Gear: Ring Gear 

    Mode: Module

    Size: 1.3 

    Teeth: 13 

    Thickness: 10 

    Clearance: 0.1 

    Backlash: 0.70

    Ring Pressure Angle: 30 

    Ring Backing: 2

  Outside Gear ( Helical Spur Gear ) 

    Gear: Spur Gear 

    Mode: Module

    Size: 0.8

    Teeth: 59 

    Thickness: 21 

    Clearance: 0.4 

    Backlash: 0

    Spur Pressure Angle: 20 

    Spur Shaft Diameter: 20 

    Spur Helical: 30

This replacement part is available for free with no warranty. Designer assumes no responsibility for any issues that may arise incident to using this replacement part.