Background

This page is about replacing the main shaft with a newly designed crank as well as gear holder, which can help to solve the issue of slippage of the gear and crank with respect to the main shaft.

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Name	Quantity	Notes
Crank	2	crank_v1_r3_1.stp crank_v1.stl
Gear holder	1	gear holder_v4a.STEP gear holder_v4a.stl
knurled shaft	2
metal shaft stopper	3
gear M=0.5  22mm (42-2A)	1	Need to punch drill by yourself
M2 nut	6
M2 x 10 bolt	6
folded cross plate	2
plastic shaft stopper (M2, orange)	4
shaft (2mm x 70mm)	1
shaft (2mm x 30mm)	2	Used for fixing when punching gearsgear and gear holder when drill the gear
Hexagonal key (1.27mm)	1

Assembly instructions:

Assemble the crank:

1. Components and tool
   1. 
2. Insert metal shaft stopper into the crank 
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1. 1. Remove the screw from the metal shaft stopper first and align the hole of the metal shaft stopper with the hole of the crank.

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1. 1.  The screw will block the metal shaft stopper to be installed into the crank, so you need to remove it first.
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   2. Insert the metal shaft stopper into the crank
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       3. Align the screw hole of the metal shaft stopper with the hole on the side of the crank, and insert the screw

1. 1. 
      1. There may be a deviation between the screw hole and the crank hole. Use a small stick metal shaft to adjust the alignment.

         4. Insert the knurled shaft with a hammer

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Assemble the gear and the gear holder:

1. Components and tools
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2. Insert metal shaft stopper into the gear holder 
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3. Insert shaft to the metal shaft stopper and the gear
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4. Align the gear holder and the gear, and drill holes on the gear for putting in bolts. You will need support with holes hole in the middle as shown for drilling.
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5. Put in the bolts and tighten
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   1. 1. 1. Pay attention to the installation direction. Align and assemble the side with the groove of the gear holder and the side with the smaller protrusion of the gear.
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      1. 1. 1. Save the screw and install it after the shaft is all completed. Installing the screw in the current step will cause the hole to be locked and the gear cannot be inserted into the shaft smoothly.
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      Assemble the cranks and gear onto the main shaft

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