Laffs J Frame Speed Loader 1.75.3 by Laffs Dynamics

A 3D printed speed loader, designed specifically for 5rd, .38Spl/.357Mag revolvers. (Some J Frames are .22 cal and carry 7-8rds)

The speed loader holds cartridges in place by their rim via a toothed spindle, the ammo is locked in place with a compliant spring catch on the release knob and detent guide channel in the rear of the cartridge holder. 

To release the cartridges from the loader, simply rotate the release knob clockwise 35 degrees. The ammo release knob is  24mm wide and is knurled to facilitate ease of handling. 

Printer Used: Ender 3 V2

Filament Used: PLA+

Print Settings:

Extruder: 218C 

Bed: 56C 

First Layer Print Height: .20mm 

Standard Layer Height: .16mm

Wall Thickness: .40 

Wall Perimeters: 5+

Infill: 32%

Support Material Percentage: 22%

Support material only needed for the detent channel at the bottom of the cartridge holder, and under the mechanically compliant spring/catch on the release knob. 

V1.75.3 Update: Updated print settings for better resulting durability. 

Hardware Required:

1x M3x12mm Hex Screw

Assembly Instructions:

1) Place the toothed spindle into the cartridge holder, in its locked position. (Refer to images for info)

2) After removing support material, (You may need a thin cutting tool and a small metal pick) with the spindle in the locked position, press the release knob onto the rear of the holder, with it's locking tab at the top most position.

3) With both spindle and release knob in place, drive the M3x12mm screw through the center of said spindle, into the knob. Once tightened, check that with each turn back and forth 35 degrees the tab clicks and locks in each position.

4) Function check the speed loader by inserting rounds into the cartridge holder, locking them in place, and releasing them from the loader. Once the spindle is in the unlocked position, the cartridges should fall away via gravity.

Troubleshooting: 

Should the cartridges remain locked in place, even when the knob and spindle have been turned 35 degree clockwise into their unlocked position; one simply needs to rotate the spindle's locking teeth slightly (by .5 degrees) closer to the unlocked position. 

Should the cartridges still stay locked in place, lightly sand the spindle's teeth on their flat sides. Test function frequently between sandings to avoid too much material loss.

Note: The newer Laffs J Frame Speed Loader V2.0.1 can be found here: https://defcad.com/library/4dd8b604-7f6c-4c87-9db5-054888a63496/