No-supports M-LOK Folding Bipod

This is a printable bipod suitable for light duty, such as an air gun or 22LR.

I based the design loosely on the Magpul bipods but there are some notable differences. I have prioritized compactness, as this bipod is intended to be used on a folding air rifle. 

You will need some metal hardware to complete. I was able to find (almost) all of this hardware at my local hardware store (ACE Hardware for the curious.)

Parts list

These you will likely have to order, unless your local sporting goods store has them. Some M-LOK screws:

• https://www.amazon.com/mlock-Screw-Standard-Screws-Replacement/dp/B08FXRKZWC/ref=sr_1_2_sspa

Through bolts for the rotating elbow joints:

• 2x - M5 button head bolts, 16mm length.
  • https://www.mcmaster.com/97763A822/
• 2x - M5 nuts, 8mm across flats. 
  • https://www.mcmaster.com/90819A112/

Either of these for the rotating elbow joints, I used the SAE spacers, but I designed it for the metric spacers. 

• 2x - 5/16" dia, #6 aluminum spacer, 5/16" long.
  • https://www.mcmaster.com/92510A523/

              -or-

• 2x - 8mm OD, M5 spacer, 8mm long
  • https://www.mcmaster.com/94669A045/

Two M3 Screws for keeping the sliders from sliding off the arms. The screw into the arm ends after insertion to keep the slider on when fully extended. They're intended to self-tap into the plastic.
 

• 2x M3 screws, 6mm long
  • https://www.mcmaster.com/95836A205/

And finally, the springs for the buttons. I designed them around a spring which is roughly 5mm in diameter and 8mm when fully compressed. These are small compression springs I could find at my local hardware store.

• 4x 5-5.8mm compression spring, max compressed length: ~8mm
  • https://www.mcmaster.com/94125K379/

Print Orientation
 

Each of the parts has a flat face that will produce minimal overhangs. I have successfully printed this design without supports in Inland PLA+ on an Ultimaker 2+. Your printer and material settings may need supports or bed adhesion support.

The contact surfaces for printing are small, so you may need to print the smaller parts in one batch, and the larger parts in another. Heated bed is required. Adhesion assist is required.

Only the sliders are mirrored. All the other parts are identical for both legs.

Settings

On my Ultimaker 2+, I used the following settings:

• 20 line wall thickness, 0.4mm nozzle
• 20% infill
• no supports, no brim.
• Heated bed.
• 0.1mm layer height.

Assembly

The sliders and arms will have burrs from printing. You'll need to put an allen key in the elbow joint and work the arms in and out of the sliders to loosen them up (lapping, if you will). You may also need to sand the contact faces for the buttons so they will slide freely as well.

The elbow bolts can set the tension on the arms from “freely drop” to “stiff”.

The buttons must be inserted with springs first, then insert the arm into the slider. If the clearance is good you should get a smooth click locking action while the slider moves up and down the arm. If it doesn't, you probably need to lightly sand the buttons and arms with 400 grit to remote burrs.

Happy plinking!