# Printing alignment pins with the 3D Print Dowel Pins Generator

> precise cylindrical pins for alignment, hinges, and repairs

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.

## What you 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.

## 3D Printing

### Print round, strong pins



1. Print standing up for roundness; a pin printed lying down has flat-spot and ellipse issues that ruin fits.
2. 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.
3. Group several pins on the plate; they support each other against wobble during printing.
4. Lightly chamfer the leading edge with a few twists in a pencil sharpener or against sandpaper for easier insertion.
5. 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.

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Open the 3D Print Dowel Pins Generator: https://www.mylasertools.com/3d-dowel-pin-generator
Read online: https://www.mylasertools.com/learn/guides/3d-dowel-pin-generator