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Print-in-place: ratchet with flexible pawls (12 teeth, one-way)

Name: Print-in-place: ratchet with flexible pawls (12 teeth, one-way) dimension sheet
Creator: Xem Studio
License: https://creativecommons.org/licenses/by/4.0/

How do you 3D print a working ratchet (one-way clutch) in one piece? · Hardware · basis: Xem Studio design: internal ratchet teeth, compliant pawl arms, 45° V-groove bearing; one designed running gap of 0.40 mm

Also called: print in place ratchet, 3d printed ratchet mechanism, one way clutch print in place, ratchet and pawl stl, compliant ratchet

Exact dimensions. True size, with no printing tolerance added.

length: 76.0 mm
width: 76.0 mm
height: 28.0 mm

Notes

3D print in place — prints already assembled, moving, in one job. Drawn at true size with no printer tolerance added; the 0.40 mm running gaps are part of the design.
Running gap 0.40 mm per side, 0.80 mm on diameter — part of the design, drawn as is. On the 45° faces the same 0.40 mm is measured square to the face (0.57 mm along the axis).
Bed: flat. The frame ring and the wheel both stand on the bed; in the bottom 6 mm layer the frame carries 12 internal ratchet teeth and the wheel two thin arms whose tips sit in tooth spaces, 0.40 mm clear.
Support while printing: above the teeth the frame closes inward as a 45° cone over the arms (0.40 mm square to the arm tips' top corners) and then wraps the wheel's raised boss with a 45° V-ridge in a V-groove; the boss and knob are plain cylinders. Nothing overhangs more than 45°.
Captured: the V-ridge in the boss's V-groove holds the wheel up and down; the boss runs in the ridge with 0.40 mm all round.
Freeing it: hold the frame and turn the knob in the free direction one full turn (12 clicks); flex each arm once with a fingertip through the top if it feels stuck.
Motion: free direction — continuous, the arm tips ride up the 3 mm ramps (bending 3.1 mm inward) and drop off each locking face: 12 clicks per turn. Locking direction — it turns 0.77° until a pawl tip meets a tooth face, then stops (computed).

Print-in-place: ratchet with flexible pawls size chart

key	value	what
gap_mm	0.4	running gap per side on every moving interface (radial, axial, under captured parts) — part of the design, not a tolerance
frame_od_mm	76.0
teeth	12	internal ratchet teeth (radial locking face, straight ramp)
tooth_depth_mm	3.0	root Ø60, tip Ø54
pawls	2	flexible arms on the wheel, 180° apart (both engage)
pawl_arm_mm	1.6 wide × 100° of arc	on Ø51.5
pawl_flex_mm	3.06	arm-tip travel inward to pass a tooth
lock_play_deg	0.77	free turn in the locking direction before a pawl meets a tooth face
clicks_per_turn	12	free direction
knob_d_mm	43.48	wheel boss / knob
axial_play_mm	0.57
height_mm	28.03	as printed
mount_holes	3 × Ø3.4	frame

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

Xem Studio

Print-in-place mechanism design (geometry computed in the generator)

web

Xem Studio design

Free files

★ Free files 3 parts. Xem Studio design: free to use, print and sell things from; not to be republished as files. Xem Studio Design License. index.json

print-in-place-ratchet-flexible-pawl-assembly	The whole print as laid on the bed (2 bodies, already assembled); STEP keeps each moving body a separate solid	STEP · STL
print-in-place-ratchet-flexible-pawl-frame	Frame ring Ø76 with 12 internal teeth, 45° cone and V-ridge bearing, 3 × Ø3.4	STEP · STL
print-in-place-ratchet-flexible-pawl-wheel	Wheel with two flexible pawl arms, boss with 45° V-groove, knob with pointer slot	STEP · STL

Let your AI pull this. Add https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.

Set it up →

Plain text: sheet.txt · JSON: /api/geometry?object=print-in-place-ratchet-flexible-pawl