EHWA DIAMOND - since 1975
Tools and application
EHWA offers impregnated core bits for exploration drilling, reaming shells for borehole guidance, casing shoes for advancing casing and diamond blades for core samples. Matrix, diamond distribution, waterways and inner/outer gauge protection are matched to the formation, drilling rig and flushing conditions. Supplementary source editions retain further documented dimensional designs.
Explorer and waterway design
Impregnated Explorer core bits combine diamond and matrix for the formation. Turbo, pie and face-discharge designs are illustrated. Waterways, crown profile and inner/outer gauge protection are selected with flushing and borehole guidance. Further crown profiles are available on enquiry; the supplementary source lists profiles for Explorer and Geo-Pro.
Technical source: Q139 p4 and Q061 p3.
ZENESIS and diamond-matrix design
ZENESIS technology uses application-specific diamond patterns. Controlled diamond distribution, a preconditioned matrix and engineered waterways support a consistent machining process. The source lists a standard diamond depth of 13 mm. Natural diamonds, carbide pads and TSP diamond protect the inner and outer gauge.
The mechanism diagram distinguishes exposed, fully embedded and pulled-out diamond grits. It supplies no specified grit sizes, spacing or matrix percentages. Cutting speed, tool life and tool design are matched to the actual formation.
Technical source: Q139 p5 and Q061 p3.
Core bits: speed and water flow
Values are catalogue guidance for the listed sizes. Water flow remains in GPM because the source does not explicitly define the gallon type. Rock, drilling machine and flushing conditions determine the actual setup.
| Size | Range [rpm] | Optimum [rpm] | Water flow [GPM] |
|---|---|---|---|
| A | 1500-1700 | 1600 | 4-5 |
| B | 1200-1450 | 1350 | 8-10 |
| N | 900-1200 | 1100 | 10-12 |
| H | 750-950 | 850 | 13-16 |
| P | 600-750 | 650 | 20-22 |
Technical source: Q139, page 2.
Impregnated core bits: standard and RSG dimensions
Original designations and both dimension columns are retained. The table heading states ±.005 without a separate unambiguous unit definition; it is not interpreted as a general ±0.005 mm tolerance.
| Source designation | Bit OD [in] | OD [mm] | ID [in] | ID [mm] | Reaming-shell OD [in] | OD [mm] |
|---|---|---|---|---|---|---|
| AO | 1.875 | 47.6 | 1.062 | 27.0 | 1.890 | 48.0 |
| BO | 2.345 | 59.6 | 1.433 | 36.4 | 2.360 | 59.9 |
| NO-3 | 2.965 | 75.3 | 1.775 | 45.1 | 2.980 | 75.7 |
| NO | 2.965 | 75.3 | 1.875 | 47.6 | 2.980 | 75.7 |
| NO-2 | 2.965 | 75.3 | 1.995 | 50.7 | 2.980 | 75.7 |
| NO-2 Oversize | 3.032 | 77.0 | 1.995 | 50.7 | 3.032 | 77.0 |
| HO-3 | 3.763 | 95.6 | 2.406 | 61.1 | 3.783 | 96.1 |
| HO-3 Oversize | 3.830 | 97.3 | 2.406 | 61.1 | 3.830 | 97.3 |
| HO | 3.763 | 95.6 | 2.500 | 63.5 | 3.783 | 96.1 |
| HO-Oversize | 3.830 | 97.3 | 2.500 | 63.5 | 3.830 | 97.3 |
| HO-Oversize | 3.850 | 97.8 | 2.500 | 63.5 | 3.850 | 97.8 |
| PO-3 | 4.805 | 122.0 | 3.270 | 83.1 | 4.828 | 122.6 |
| PO | 4.805 | 122.0 | 3.345 | 85.0 | 4.828 | 122.6 |
Technical source: Q139, page 3.
Additional dimensional variants from the older source
The following five rows are absent from the newer 13-row table. They remain distinct dimensional variants with source provenance.
| Source designation | Bit OD [in] | OD [mm] | ID [in] | ID [mm] | Reaming-shell OD [in] | OD [mm] |
|---|---|---|---|---|---|---|
| AWG, AWM | 1.875 | 47.6 | 1.185 | 30.1 | 1.890 | 48.0 |
| ADBGM | 1.875 | 47.6 | 1.193 | 30.3 | 1.890 | 48.0 |
| BWG, BWM | 2.345 | 59.6 | 1.655 | 42.0 | 2.360 | 59.9 |
| NWD-4 | 2.980 | 75.7 | 2.060 | 52.3 | 2.980 | 75.7 |
| NWG, NWM | 2.965 | 75.3 | 2.155 | 54.7 | 2.980 | 75.7 |
Technical source: Q061, page 7.
Zenesis and Explorer: rock selection
The map connects rock characteristics with Zenesis and Explorer series. Abrasive formations are on the left, competent rock on the right. The two hardest Explorer columns share Zenesis #10; the six comparison ranges remain separate.
| Hardness class | Zenesis | Explorer | Rock formations | Series comparison |
|---|---|---|---|---|
| Soft | #2 | 1 | Claystone, Calcite, Sandstone, Serpentine | 1-3 |
| Medium | #4 | 2 | Dolomite, Schist, Peridotite, Barite | 4-5 |
| Medium-hard | #6 | 3 | Basalt, Diorite, Quartz, Volcanics | 6-7 |
| Hard | #8 | 4 | Pegmatite, Gneiss, Granite, Porphyry | 8-10 |
| Extremely hard | #10 | 5 | Jasterite, Rhyolite, Quartzite, Chert | 11-12 |
| Extremely hard | #10 | 6 | Jasterite, Rhyolite, Quartzite, Chert | 13-15 |
Technical source: Q139, page 7.
Explorer and Geo-Pro: supplementary matrix mapping
The older source gives separate mappings for five Explorer and four Geo-Pro series. This matrix is not identical to the six-column Explorer/Zenesis comparison. The programmes remain separate. Explorer and Geo-Pro list sizes A, B, N, H and P, with oversize options on request.
| Programme | Series | Formation description |
|---|---|---|
| Explorer | I | Extremely abrasive, broken, coarse, fractured: shales, limestone, sandstone |
| Explorer | II | Abrasive, medium/coarse grain, solid/fractured: dolomite, granite, peridotite |
| Explorer | III | Moderately abrasive, medium/fine grain: basalt, diorite, quartz, volcanics |
| Explorer | IV | Low abrasive, hard/very hard: diorite, granite, gneiss, quartzite |
| Explorer | V | Extremely hard, non-abrasive: jasterite, rhyolite, quartzite |
| Geo-Pro | I | Extremely abrasive, fractured, coarse grain |
| Geo-Pro | II | Abrasive to moderately abrasive, fractured |
| Geo-Pro | III | Slightly abrasive, medium hard |
| Geo-Pro | IV | Extremely hard, low abrasive, solid |
Technical source: Q061, page 3.
Core-sample cutting blades
For core samples on table or bridge saws. The source length field 40 is retained as the source field “Length”; the table lists height values of 10/12 and maximum operating speed 63 m/s. Length, thickness and height have no explicitly printed unit in the header and are checked against the drawing.
| Nominal diameter | Length | Thickness | Height | Max. peripheral speed |
|---|---|---|---|---|
| 12 in (300 mm) | 40 | 2.8 / 3.2 | 10 / 12 | 63 m/s |
| 14 in (350 mm) | 40 | 2.8 / 3.2 | 10 / 12 | 63 m/s |
| 16 in (400 mm) | 40 | 3.2 | 10 / 12 | 63 m/s |
| 18 in (450 mm) | 40 | 3.2 | 10 / 12 | 63 m/s |
Technical source: Q139, page 6.
Casing shoes and reaming shells
Explorer casing shoes combine concentrated diamond, natural diamonds and inner/outer gauge wear protection. Heavy-duty reaming shells add natural diamonds, carbide pads and TSP to the matrix. The older source additionally lists standard reaming shells, Geo-Pro casing shoes, and two-, three- or four-ring stabilisation designs.
| Design | Sizes / dimensions |
|---|---|
| Explorer casing shoe standard | BW, NW, HW, PW; diamond depth 0.250 in |
| Explorer casing shoe oversize | NW, HW; diamond depth 0.315 in |
| NW oversize shoe | OD 3.875 in x 2.992 in |
| HW oversize shoe | OD 4.875 in x 3.975 in |
| Heavy-duty reaming shell standard | B, N, H, P |
| Heavy-duty reaming shell oversize | N 3.032 in; H 3.830 / 3.850 in; P 4.900 in |
| Geo-Pro casing shoe (Q061 p4) | BW, NW, HW, PW; diamond depth 0.250 in |
| Standard reaming shell (Q061 p5) | B, N, H, P |
| Reaming shell stabilisation (Q061 p5) | Two-, three-, four-ring designs |
Technical source: Q139, page 6.
Source variant OE30P: wet concrete drilling
The older source lists OE30P for hard or cured concrete, reinforced concrete, concrete brick and blocks. Equipment: electric, gasoline or hydraulic core drills. Standard core length 14 inches; other lengths on request.
| Code | Source dimensions [in] | Segment height |
|---|---|---|
| OE30P02014A | 2 x .145 x 1 1/4-7 | 8 mm D |
| OE30P02214A | 2 1/4 x .145 x 1 1/4-7 | 8 mm D |
| OE30P02514A | 2 1/2 x .145 x 1 1/4-7 | 8 mm D |
| OE30P02714A | 2 3/4 x .145 x 1 1/4-7 | 8 mm D |
| OE30P03014A | 3 x .145 x 1 1/4-7 | 8 mm D |
| OE30P03214A | 3 1/4 x .145 x 1 1/4-7 | 8 mm D |
| OE30P03514A | 3 1/2 x .145 x 1 1/4-7 | 8 mm D |
| OE30P04014A | 4 x .145 x 1 1/4-7 | 8 mm D |
| OE30P04214A | 4 1/4 x .145 x 1 1/4-7 | 8 mm D |
| OE30P04514A | 4 1/2 x .145 x 1 1/4-7 | 8 mm D |
| OE30P05014A | 5 x .145 x 1 1/4-7 | 8 mm D |
| OE30P05514A | 5 1/2 x .145 x 1 1/4-7 | 8 mm D |
| OE30P06014A | 6 x .145 x 1 1/4-7 | 8 mm D |
| OE30P06214A | 6 1/4 x .145 x 1 1/4-7 | 8 mm D |
Technical source: Q061, page 6.
Source variant OA30P: wet asphalt drilling
For asphalt and abrasive concrete. The older source lists electric, gasoline or hydraulic core drills and standard core length 14 inches.
| Code | Source dimensions [in] | Segment height |
|---|---|---|
| OA30P04214A | 4 1/4 x .145 x 1 1/4-7 | 8 mm D |
| OA30P04514A | 4 1/2 x .145 x 1 1/4-7 | 8 mm D |
| OA30P05014A | 5 x .145 x 1 1/4-7 | 8 mm D |
| OA30P06014A | 6 x .145 x 1 1/4-7 | 8 mm D |
| OA30P06214A | 6 1/4 x .145 x 1 1/4-7 | 8 mm D |
Technical source: Q061, page 6.
Source variant SB10UT: wet core-sample cutting
These three coded blades remain separate from the newer Zenesis dimension table. Equipment: table or bridge saws.
| Code | Source dimensions [in] | Segment height |
|---|---|---|
| SB10UT1409EN | 14 x .090 x 1 | 10 mm D |
| SB10UT1812EN | 18 x .125 x 1 | 10 mm D |
| SB10UT2012EN | 20 x .125 x 1 | 10 mm D |
Technical source: Q061, page 6.
Match your application
State formation, drilling system, size designation, outside/inside diameter, matrix and waterway. Add spindle speed, flushing, required diamond depth and wear pattern. Supplementary regional source designs are checked for specification and current supply using their codes.
EHWA Europe: info@ehwadia.de · +49 6173 997780
Editorial date: 14 October 2026.
Questions about tool selection
Which diamond tools are included in the EHWA exploration programme?
The programme includes impregnated core bits, Explorer and ZENESIS designs, reaming shells for borehole guidance, casing shoes and blades for cutting core samples. Dimensions and matrix data are listed in the respective product sections.
How are a core bit and matrix selected?
Selection combines the rock formation, drilling equipment, flushing and waterways with matrix and diamond distribution. Inner and outer gauge protection and the required crown profile are specified for the drilling task.