Regular price
Rs. 2,241.00
Sale price
Rs. 1,199.00
Rs. 1,415 incl. GST · you save Rs. 826
36% BELOW MRP
Sale
A clearance hole is a hole slightly larger than the bolt, so the bolt passes through freely. For an M8 bolt in the medium series, drill 9.0 mm; the fine series gives 8.4 mm and the coarse series 10.0 mm. The chart below covers M2 to M24 in the three series of ISO 273.
Clearance hole chart, M2 to M24
All values are the hole diameter in millimetres.
Bolt
Fine (close)
Medium (normal)
Coarse (free)
M2
2.2
2.4
2.6
M2.5
2.7
2.9
3.1
M3
3.2
3.4
3.6
M4
4.3
4.5
4.8
M5
5.3
5.5
5.8
M6
6.4
6.6
7.0
M8
8.4
9.0
10.0
M10
10.5
11.0
12.0
M12
13.0
13.5
14.5
M14
15.0
15.5
16.5
M16
17.0
17.5
18.5
M18
19.0
20.0
21.0
M20
21.0
22.0
24.0
M22
23.0
24.0
26.0
M24
25.0
26.0
28.0
Which series to use
The medium (normal) series is the general-purpose default. Use the fine series for closely toleranced joints, where the bolt must sit close to its hole. Use the coarse series where the holes may be out of position and the bolt must still pass through. ISO 273 gives hole tolerances of H12 for fine, H13 for medium and H14 for coarse.
Clearance holes and tap drills are different
A clearance hole lets the bolt pass through. A tapped hole is smaller, so the thread can be cut into it. For tapped hole sizes, see the tap drill size chart.
Drills for these holes
The IT Brand HSS jobber drill packs on BVF cover 1.00 to 13.00 mm, so they include the medium-series sizes up to M10: 3.00 - 3.90 mm for M3 (3.4 mm), 4.00 - 4.90 mm for M4 (4.5 mm), 5.00 - 5.90 mm for M5 (5.5 mm), 6.00 - 6.90 mm for M6 (6.6 mm), 9.00 - 9.90 mm for M8 (9.0 mm) and 11.00 - 11.90 mm for M10 (11.0 mm). Each product page lists every size in its pack. Holes above 13 mm (M12 medium series and above) are larger than the sizes in these packs.
What to check
Pick the series first, then read the diameter for your bolt from the chart.
Check that the drill size you need is in the pack before ordering.
