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Drill bits size description
Drill bits are the cutting tools of drilling machines. They can be made in any size to order, but standards organizations have defined sets of sizes that are produced routinely by drill bit manufacturers and stocked by distributors.
In the U.S., fractional inch and gauge drill bit sizes are in common use. In nearly all other countries, metric drill bit sizes are most common, and all others are anachronisms or are reserved for dealing with designs from the US. The British Standards on replacing gauge size drill bits with metric sizes in the UK was first published in 1959.
Impregnated diamond core drill bit size
| Double tube surface | ||||
Size( surface exploration drill | Matric system(mm) | Imperial system( in ) | ||
Hole diameter | Core diameter | Hole diameter | Core diameter | |
BQ | 60 | 36.4 | 2.36 | 1.43 |
NQ | 75.7 | 47.6 | 2.98 | 1.88 |
HQ | 96.1 | 63.5 | 3.78 | 2.5 |
PQ | 122.7 | 85 | 4.83 | 3.34 |
Triple tube surface | ||||
NQ3 | 75.7 | 45 | 2.98 | 1.78 |
HQ3 | 96.1 | 61.1 | 3.78 | 2.41 |
PQ3 | 122.7 | 83 | 4.83 | 3.27 |
