Where a 10 mm guide is used
Ten millimetres is the largest of the common dowel sizes, used for bed rails, bench frames and thick table tops, and it is the hole many M8 threaded inserts and M10 bolts call for; read the size on the insert's own data sheet before drilling. These are structural joints in thick stock, usually 30 mm or more, which is why the hole here sits 30 mm from the edge: on the centre line of a 60 mm rail. For 40 mm stock set the offset to 20.
What to measure
Measure the thickness of the workpiece and halve it for a centred hole, or measure the mating part if the hole has to meet something that already exists. Measure the bit as well. A brad-point wood bit of 10 mm has spurs at the full diameter and fits the 10.2 mm hole closely; a twist bit ground for metal is the same diameter but wanders on entry in wood, and the guide is what stops it. If you own a hardened drill bushing, measure its outside diameter, often 14 or 15 mm for a 10 mm bore, and type that as the guide hole so the bushing presses in.
Block, fence and material
At this size the forces go up sharply: a 10 mm bit that catches will try to spin the jig. So the block is 18 mm thick, the fence 8 mm thick and 15 mm high, and the jig is 100 mm long to give a clamp somewhere to sit on each side of the hole. Always clamp it. A plain printed hole of 10 mm wears quickly, because the flutes of a large bit scrape the wall; for more than a handful of holes the bushing is worth it. Print in PLA or PETG; PETG is less likely to crack if the bit grabs.
Printing
Print fence up, 100 by 65 mm on the bed and 33 mm tall, with no supports. This is a thick part, and its strength comes from the shells: use six perimeters, six solid layers above and below, and 40 to 50 percent infill. Expect it to use far more filament than the smaller guides. Leave it on the bed until cool so the wide base stays flat, since a rocking jig drills a leaning hole.
Outline drawing
To scale. Left: top view as printed, fence along the top edge. Right: end view, block 18 mm thick with the fence rising 15 mm above it.
Parameters the generator will use
| Setting | Link parameter | Value |
|---|---|---|
| Model | model | drill_jig |
| Jig length along the edge (X) | length | 100 |
| Jig width including the fence (Y) | width | 65 |
| Block thickness | thickness | 18 |
| Guide hole diameter | hole_diameter | 10.2 |
| Hole centre to workpiece edge | offset | 30 |
| Hole position along the length (0 centres it) | hole_position | 0 |
| Fence thickness | fence_thickness | 8 |
| Fence height | fence_height | 15 |
All lengths are in millimetres. Outer size from these values: 100 x 65 x 33 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.