Printing alignment pins with the 3D Print Dowel Pins Generator

Difficulty: easy. Time: 2 minutes to design, minutes to print. Method: 3D printing only.

A dowel pin is the simplest part in engineering and the one you need at the worst moments: a missing shelf pin, a snapped hinge pin in a toy, an alignment dowel for a glue-up, a pivot for a printed mechanism. This generator makes a clean cylinder at exactly the diameter and length you ask for, which beats whittling a hardware-store dowel every time.

Because you control diameter to the fraction of a millimeter, you can deliberately print for the fit you want: snug press fit, smooth sliding fit, or loose pivot fit, just by nudging the diameter against the hole size.

Open the 3D Print Dowel Pins Generator

What You'll Need

Any FDM 3D printer
PETG or PLA; PETG for pins that flex or pivot, PLA for static alignment
Calipers to measure the hole the pin must fit

Step 1 - Measure the hole

Open the tool, set your Units, and measure the bore the pin will live in. Pick the fit: for a press fit, set Diameter equal to the hole; for a sliding fit, subtract about 0.2 mm; for a free pivot, subtract 0.3-0.4 mm. Printers vary, so the first pin is always a test pin.

Step 2 - Set the length

Set Length to span the assembly. For alignment dowels between two parts, the classic rule is half the pin in each side; for hinge pins, match the knuckle stack with a hair of clearance.

Step 3 - Export

Download STL or 3MF and print a handful; spare pins weigh nothing and always disappear.

Choose Your Build Method

Print round, strong pins

Print standing up for roundness; a pin printed lying down has flat-spot and ellipse issues that ruin fits.
Vertical pins put layer lines across the bending axis, so for high-shear hinge pins print at 0.12 mm layers with 100 percent infill, or print lying down and accept light sanding.
Group several pins on the plate; they support each other against wobble during printing.
Lightly chamfer the leading edge with a few twists in a pencil sharpener or against sandpaper for easier insertion.
Test the fit in the real hole and adjust diameter by 0.1 mm steps; two test pins usually nail it.

Make It Yours

Replacement shelf pins for bookcases, in exactly the metric or odd vintage diameter the cabinet uses.
Hinge pins to revive toys, glasses cases, and small box hinges.
Alignment dowels for two-part epoxy glue-ups and woodworking jigs.
Axles for printed toy cars and pull-along animals.
Pegboard pegs in custom lengths that actually stay in the holes.
Registration pins for repeatable laser jig positioning on your cutter bed.
Pair with the Chicago Screw Generator when the pin needs a removable head on both ends.

Open the 3D Print Dowel Pins Generator

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