Modular Drill Jig with Replaceable Bushings

Parametric drilling jig for accurate vertical drilling into square stock, round dowels and flat boards.
Designed for hobby woodworking and fully customizable.

 

Supports:

square timber
round stock
flat boards
interchangeable drill bushings
adjustable hole spacing
variable rail length

 

Printable in PETG or ASA without supports.

 

Parametric Drill Guide Jig

This project is a fully parametric drill guide designed for hobby woodworking and workshop use.

 

The jig allows accurate perpendicular drilling into:

square timber
round stock
flat boards

 

The model was designed with fully adjustable parameters, allowing easy customization for different drilling setups and material sizes.

 

Main Features
Fully Parametric

 

You can easily customize:

rail length
hole count
hole spacing
arm thickness
drill diameter
fastener size
embedded nut option

 

The rail length updates automatically based on:

number of holes
hole spacing

Replaceable Drill Bushings

Bushings are fully replaceable and can be printed separately.

 

Supported Materials

The jig can be used for:

square beams
round dowels
flat boards

 

Recommended working range:

square stock: approx. 20–80 mm
round stock: approx. Ø20–65 mm
 

Printing Recommendations
Recommended Materials
PETG
ASA

PETG works surprisingly well even for the guide bushings.

ASA is recommended for:

higher wear resistance
workshop environments
long-term durability
 

Print Settings
Suggested Settings
Nozzle: 0.4 mm
Layer height: 0.2 mm
Walls: 4–5
Infill: 25–40%
Infill type: Gyroid
Supports: Not required
Important Notes

The bushings are also printable in PETG or ASA.

 

Because every printer and filament behaves differently, hole tolerances may require small adjustments depending on:

printer calibration
filament shrinkage
extrusion tuning

 

If needed, slightly adjust the bushing clearance in the parameters.

 

Adjustable Parameters
Parameter    Description
P_arm_length    Arm length
P_hole_count    Number of guide holes
P_hole_spacing    Hole spacing
P_rail_height    Rail height
P_arm_thickness    Arm thickness
P_fastener_size    M4 / M5 / M6
P_drill_diameter    Drill diameter
P_embedded_nut    Embedded nut YES/NO
Assembly

 

Required hardware:

screws according to selected fastener size
matching nuts
printed bushings

Assembly is simple and requires only basic hand tools.

 

Why This Design?

Most printable drill guides are fixed-size models.

This design was created to be:

modular
repairable
adjustable
scalable
easy to customize

 

The goal was to create a workshop-friendly drilling jig that can be adapted instead of re-designed.

Boost MeIf you like the project and want to support more fully parametric workshop tools, a Boost is greatly appreciated.
I plan to expand the system with additional guides, bushings and woodworking accessories.