Where a 4 mm guide is used
Four millimetres is the size for the machine screws of most cabinet knobs and pulls, which are M4, and a usual pilot size for 6 mm wood screws in hardwood. Both are jobs where the same hole is repeated along an edge: a row of drawer fronts, a run of hinges, battens along a shelf. Marking each one with a square takes longer than drilling and drifts a little each time. With the fence against the edge, only the position along the edge has to be marked, as a pencil line that you sight through the hole or line up with the end of the jig.
What to measure
Measure your drill bit, not the label on its box: a 4 mm bit is usually 3.95 to 4.0 mm, and the 4.2 mm guide hole used here leaves it a running fit. Then decide the offset. It is measured from the face of the fence that touches the board to the centre of the hole, so 15 mm puts the hole centre exactly 15 mm from the board edge. For a handle screw that needs room to adjust, keep the jig as it is and open the hole in the workpiece afterwards with a 5 mm bit.
Block, fence and material
The block is 10 mm thick, two and a half times the bit diameter, which is about the least that keeps a thin bit from leaning. A 4 mm bit bends easily, so let the guide do the steering and use light pressure. The fence is 5 mm thick and 10 mm high: enough to register on a 12 mm board without touching the bench beneath it. PLA is the right material, being harder than PETG, and a plain printed hole of this size wears slowly if the bit is spinning before it enters.
Printing
The jig is modelled fence up, and that is how it prints: 70 by 45 mm on the bed, 20 mm tall, no supports. The guide hole is vertical in this position, so it comes out round. Use five perimeters, or enough that the hole sits in solid plastic, and 40 percent infill for the rest. Small vertical holes print slightly under size; run the bit through once at low speed to clear it.
Outline drawing
To scale. Left: top view as printed, fence along the top edge. Right: end view, block 10 mm thick with the fence rising 10 mm above it.
Parameters the generator will use
| Setting | Link parameter | Value |
|---|---|---|
| Model | model | drill_jig |
| Jig length along the edge (X) | length | 70 |
| Jig width including the fence (Y) | width | 45 |
| Block thickness | thickness | 10 |
| Guide hole diameter | hole_diameter | 4.2 |
| Hole centre to workpiece edge | offset | 15 |
| Hole position along the length (0 centres it) | hole_position | 0 |
| Fence thickness | fence_thickness | 5 |
| Fence height | fence_height | 10 |
All lengths are in millimetres. Outer size from these values: 70 x 45 x 20 mm.
Open the generator with these values
This model needs the $7 licence key: one payment, one key, and it opens all five paid models. Get a licence key on Gumroad ($7)
The drill guide jig needs a licence key: without one the generator shows the model locked, lists the values from this link and fills them in as soon as you unlock. The fitted drawer organiser bin is the free model and downloads with no key.