Axle Benders for Pinewood Derby Cars

I've designed two different print in place support free axle benders for pinewood derby cars.  They are used to bend standard axles, 0.087 inches in diameter by 1 inch long.  One is a hardware free version that bends a single angle ~ 3 degrees.  The second version requires some hardware, allows angle adjustment, and provides increased clamping force.

Both benders uses a print in place flexure hinge to align the bend axis with the top of the nail for an optimal bend location.  There are also bend angle gauges on the right side of the unit to check your bent axles.  You can also print and use a large angle gauge found HERE.

Print Settings

• Material: PLA
• Nozzle Size: 0.4mm
• Layer Height: 0.2mm
• Perimeters: 4
• Infill: Gyroid 15%
• Supports: None

Post Processing 

There are two stops at the zero position that may slightly fuse during printing.  It may be necessary to pop the bending section free with a screw driver after printing.

Note

If the triangular flash under the nail head has not been removed make sure to align flash with slot when inserting axle

No Hardware Version

For the no hardware version a second nail is wedged above the nail to be bent  and provides clamping force.

Operation

• Insert the nail, aligning flash with slot if present
• Engage clamp by inserting and wedging second nail into upper hole
• Lift up and tap the end stop, repeat a few times
• Check angle with angle gauges on side of bender

Hardware Version

This version has an adjustable stop with lock nut that allows custom repeatable bends.  The axle is held in place with a screw clamp.

Operation

• Set the bending stop to a specific angle using the angle gauge on left side of the bender (I found ~12 degrees produced a bend close to 3 degrees)
• Insert the nail, aligning flash with slot if present
• Engage clamp by tightening knob
• Lift up and tap the end stop, repeat a few times
• Check angle with angle gauges on side of bender

Required Hardware

This version requires the following hardware:

• 2X M3 Hex Nut
• 1X M3 Lock Nut
• 1X M3 x Long SHCS
• 1X M3 x 25mm Long SHCS

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