Drill holes for screws

Place the holes

Each tap on a flat face puts a hole there. One Hole step drills one face, with as many holes as you like.

Tap Hole in the tool strip, or press H.
Tap the face you want to drill. The first tap chooses the face and places a hole.
Tap again for each hole you want to add. Tap a hole to take it out.
Tap Done.

A 60 by 30 mm plate with two holes on its top face, each marked with a blue cross. The Hole 1 inspector shows 2 holes picked, the M3 socket head counterbore preset and Extent set to Through all. — A blue cross marks each hole while the step is open.

If a flat face is already selected, choose Drill holes in this face under Next in the inspector instead. To change a hole later, tap its step on the timeline.

Holes go into flat faces only. To drill a second face, tap Done and start another Hole. On a Mac, click where this guide says tap.

Pick a screw

The Preset menu has holes for metric screws from M2 to M6. Choose what the hole is for, then the size.

Tap the Preset menu. A new hole says Custom sizes.
Choose a fit, such as Socket head counterbore.
Choose the size, such as M3.

The Preset menu open: Clearance, Socket head counterbore, Flat head countersink, Tap (self-tapping), Heat-set insert and Keep sizes, drop preset. Socket head counterbore is expanded to show M2 to M6, with a checkmark on M3. — Fit first, then size. The checkmark is the current preset.

The preset fills in the sizes, and you can still change them. The label then reads (edited). Every size is listed under Screw sizes.

Tune the fit for your printer

Printed holes come out a little small. So clearance, counterbore and countersink holes add a parameter named clearance to their diameters. It starts at 0.2 mm. Tap and insert holes have to grip, so they leave it out.

Print a test plate with one hole and try the screw.
In the browser, under Parameters, raise clearance if the screw binds, or lower it if it wobbles. Go in steps of 0.1 mm. Every hole that uses it updates at once.

The Parameters list in the browser with clearance set to 0.2 mm. — One parameter widens every screw hole in the design.

The Hole inspector. Diameter reads 3.4 + clearance, which works out to 3.6 mm, and Bore diameter reads 6.5 + clearance, which works out to 6.7 mm. — One parameter widens every screw hole in the design.

Set the sizes yourself

Skip the preset, or change any size it filled in. Every field takes a number, an expression or a parameter.

Type: Simple, Counterbore (adds a bore for the screw head) or Countersink (adds a cone).
Extent: Through all goes out the other side. Distance stops at Depth.
Drill point: Angled ends in a cone like a twist drill. Flat gives a flat bottom.

The Hole inspector for a plain hole: Type Simple, Diameter 5 mm, Extent Distance, Depth 8 mm, Drill point Angled and Point angle 118°. — A plain 5 mm hole, 8 mm deep, with a drill-bit tip.

Put holes at exact spots

Taps land on a 0.1 mm grid, so a hole you tap near 20 mm may read 20.1. Type the exact value to fix it.

Scroll down the inspector to Positions.
Type the hole’s X and Y.

X and Y are measured from the origin, as if you were looking straight at the face.

To tie a hole to a parameter, type an expression such as width / 2 - 6. Plain numbers stay put when the part changes size.

Positions in the Hole inspector: Hole 1 at X -19.8 and Y 0, Hole 2 at X 20.1 and Y -0.1, in mm. — Two tapped holes. Type over a value to place one exactly.

Repeat holes in a pattern

For a row or ring of the same hole, make one hole and repeat its step.

Touch and hold the Hole step on the timeline, then tap Pattern.
Set Count and Spacing.
Tap Done.

An 80 mm plate with four counterbored holes in a row. The Pattern 1 inspector shows Objects set to Features, Hole 1 picked, Type Linear, Axis X, Count 4 and Spacing 20 mm. — One hole, four times: Count 4, 20 mm apart along X.

Every copy is a real hole, and it follows the first one when you change its size. More in Repeat with patterns.

Screw sizes

What each fit is for, and the sizes it uses. All sizes are in mm.

What each fit is for

Fit	Use it for
Clearance	A screw that passes through freely.
Socket head counterbore	A cap screw whose head sits flush in a flat-bottomed recess.
Flat head countersink	A flat head screw whose head sits flush in a 90° cone.
Tap (self-tapping)	A screw that cuts its own thread in the plastic.
Heat-set insert	A brass insert you press in with a soldering iron.

Sizes from M2 to M6

Size	Clearance	Bore	Sink	Tap	Insert
M2	2.4	4.4 × 2	4.7	1.8	3.2 × 5
M2.5	2.9	5.5 × 2.5	5.88	2.25	4 × 6.7
M3	3.4	6.5 × 3	6.72	2.7	4 × 6.7
M4	4.5	8 × 4	8.96	3.5	5.6 × 9.1
M5	5.5	10 × 5	11.2	4.4	6.4 × 10.5
M6	6.6	11 × 6	13.44	5.2	8 × 13.7

Bore and insert are diameter × depth. Counterbore and countersink holes also take the clearance diameter, and clearance, bore and sink diameters get clearance added. Only the insert preset sets a depth: it switches Extent to Distance, 1 mm deeper than the insert.

Clearance holes follow ISO 273. Counterbores follow DIN 974-1 for ISO 4762 cap screws. Countersinks are 90° cones for ISO 10642 heads. Tap holes are the tap drill plus 0.2 mm. Insert holes come from the Ruthex and CNC Kitchen sheets, so check your maker’s sheet if you use another brand.