Corner Rounding Guide for Trim Routers

A 3D-printable guide designed for rounding the corners of wooden boards and similar workpieces with a trim router.

The guide is intended for use with Makita trim routers and other similarly sized handheld routers. Interchangeable guide inserts allow you to create different corner radii using a bearing-guided router bit.

Included Parts

Base plate
Two side guides
Knob with screw
Interchangeable corner guide inserts

Included Corner Radii

Metric versions:

10 mm
15 mm
18 mm
20 mm
25 mm
30 mm
35 mm

Imperial versions:

1/4 in (6.35 mm)
1/2 in (12.7 mm)
1 in (25.4 mm)
1.5 in (38.1 mm)

Recommended Print Settings

Infill: Infill: At least 40% when printing with relatively soft materials (PETG, PLA etc.). Stronger materials, such as PC, ASA, or ABS, are recommended.
Printed M6 × 20 mm screw: At least 50% infill. However, a metal M6 × 20 mm bolt is recommended for improved strength and durability.
Layer height: 0.2 mm or less
Supports: Use only if required by the selected print orientation.
It is recommended to print the STL files in their default orientation, as loaded, with supports enabled.

Assembly

Press the two side guides into their slots in the base plate until they are fully seated.
Insert either the included 3D-printed M6 × 20 mm screw or a metal M6 × 20 mm bolt through the base plate, then screw the knob onto it. A metal bolt is recommended for improved strength and durability.
Install the required corner guide insert by pressing it into place until it locks securely.
To remove the corner guide insert, press directly on the locking tab and pull the insert out.
Make sure all parts are properly seated and tightened before use. Do not overtighten the knob.

Use

The guide can be secured to the workpiece with clamps or held firmly in place by hand while routing, provided your hands remain safely clear of the router bit. It can also be used on a router table by moving the workpiece along the guide.
For the best result, remove most of the excess material with a saw before routing. Leave only a small amount of material for the router bit to remove.
Use a bearing-guided router bit and allow the bearing to follow the curved guide surface. Avoid pressing the router or bearing unnecessarily hard against the guide.
Always route in a controlled direction and keep your hands clear of the cutter.

The parts shown in the photos were printed in PLA and PETG. However, polycarbonate (PC) or another strong and impact-resistant material, such as ASA or ABS, is recommended for improved durability.

Important

Avoid applying excessive force to the printed parts. Strong clamping pressure or forcing the router bit bearing against the guide may crack the plastic, especially if the parts are printed with low infill or from a relatively soft or brittle material.

The guide is an alignment aid and must not be used as a substitute for securely controlling the router or workpiece. Inspect all printed parts for cracks or damage before each use.

This model is provided as-is, without warranty. Use it at your own risk. Always wear appropriate eye protection and keep your hands and fingers clear of the router bit.

Disclaimer

This is an independent 3D printable accessory and is not affiliated with, endorsed by, or sponsored by Makita.

Note

The same version of this model is also available on Printables. For documentation, printing instructions, updates, and the changelog, visit: https://www.printables.com/model/1786858-corner-rounding-guide-for-trim-routers

License

Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
You are free to:

Share — copy and redistribute the model in any medium or format
Adapt — remix, transform, and build upon the model
Use commercially

Under the following terms:

Attribution — You must give appropriate credit to the original author
ShareAlike — If you modify the model, you must distribute your contributions under the same license

This model is provided as-is, without warranty. Use at your own risk.