Hole and pocket sizes for metric hardware in 3D-printed parts, M3 through M10, in millimeters. Press fit is for nuts that stay put; slip fit is for nuts and bolts that need to drop in. Based initially on the hardware design boards from alch.shop. Hardware sizes and offsets managed in a hardware.yaml file.
Bolt hole
M3
M4
M5
M6
M8
M10
ASlip fit Ø
3.3
4.3
5.3
6.3
8.3
10.3
Hex nut pocket
M3
M4
M5
M6
M8
M10
APress fit, across flats
5.5
6.9
7.9
9.9
12.8
16.9
ASlip fit, across flats
5.7
7.2
8.2
10.3
13.2
17.2
BDepth (nut thickness)
2.5
3.2
4.1
5.1
6.5
8.1
Square nut pocket
M3
M4
M5
M6
M8
M10
APress fit width
5.4
6.8
7.9
9.9
12.9
17.1
ASlip fit width
5.8
7.2
8.3
10.4
13.4
17.3
BDepth (nut thickness, slip)
2.1
2.4
2.9
3.5
4.4
5.3
Square nut vertical slot
M3
M4
M5
M6
M8
M10
ASlot width (nut thickness, slip)
2.1
2.4
2.9
3.5
4.4
5.3
BSlot depth and length, slip
6.3
7.6
8.7
10.9
13.9
17.8
Hex head pocket
M3
M4
M5
M6
M8
M10
APress fit, across flats
5.6
7.0
8.0
10.0
12.9
17.0
ASlip fit, across flats
5.8
7.3
8.3
10.4
13.3
17.3
BDepth (head height)
2.4
3.3
4.1
4.4
5.8
7.0
CThrough hole Ø (bolt slip fit)
3.3
4.3
5.3
6.3
8.3
10.3
Counterbore (socket head cap screw)
M3
M4
M5
M6
M8
M10
ACounterbore Ø
5.6
7.3
8.9
10.4
13.2
16.3
BCounterbore depth
3.1
4.1
5.2
6.3
8.2
10.0
CThrough hole Ø (bolt slip fit)
3.3
4.3
5.3
6.3
8.3
10.3
Counterbore Ø with washer
7.3
9.1
10.4
12.3
16.2
20.2
Counterbore depth with washer
3.7
5.0
6.3
8.0
9.9
12.1
With a washer: Ø = washer Ø, depth = counterbore depth + washer thickness.
Countersink (flat head screw)
M3
M4
M5
M6
M8
M10
ACountersink Ø
6.3
8.2
10.2
12.3
16.2
20.2
BCountersink depth
2.1
2.4
3.2
3.6
5.0
5.7
CChamfer width
1.5
2.0
2.5
3.0
4.0
5.0
C = (A − bolt slip fit) ÷ 2. Through hole is the bolt slip fit Ø.
Bolts, screws, and nuts
Hex head bolts are zinc-plated Class 8.8 steel (DIN 933), socket head cap screws and flat head screws are 18-8 stainless steel (DIN 912 and DIN 7991), and hex nuts are zinc-plated Class 8 steel (DIN 934), all from McMaster-Carr.