Changsha Drilling Machinery CO., LTD
Changsha Drilling Machinery CO., LTD
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Surface-Set Diamond Bit
The surface set diamond bit is produced from a single layer of natural diamond setting on the surface of bit crown with hard matrix.
Surface set diamond bit is mainly recommended for drilling soft to hard formations. Generally speaking, surface set diamond bit can provide satisfying penetration rate.
In order to confirm the surface-set bit quality, we have to confirm the following information:
Diamond sizes (spc – stones per carat)
As a general rule; the softer formation, the larger the diamonds used i.e. 20 to 25 spc. In hard formation, smaller diamonds 30 to 50 spc are typical
Diamond Size | Formation Drilled |
10/20 SPC | Soft formation |
20/30 SPC | Soft to medium formation |
30/40 SPC | Medium formation |
40/60 SPC | Medium to hard formation |
60/80 SPC | Very hard formation |
Diamond quality
The standard range of natural diamonds for surface set bits is chosen in a special allround grade with special quality. The quality includes selected and processed diamonds with a highly polished surface. These stones have a high impact resistance and may be considered as an universal type. Recommended for soft to medium hard formations.
Diamond Grade | Formation Drilled |
A Grade | Soft formation |
AA Grade | Sort to medium formation |
AA Grade | Hard to very hard formation |
Diamond size range (SPC) | Actual number of stone per carat | Diamond size | |
inch | mm | ||
6~8 | 6~8 | 0.098 | 2.49 |
10 | 9~12 | 0.085 | 2.16 |
15 | 13~20 | 0.071 | 1.80 |
25 | 21~35 | 0.063 | 1.56 |
50 | 36~60 | 0.054 | 1.37 |
75 | 61~90 | 0.044 | 1.12 |