NTW, NQ and HQ are useful series references, but an order needs enough detail to match the bit, barrel and sampling task. Use this checklist when comparing spiral PDC core bits and hot-pressed NTW core bits.
1. Identify the barrel and cutting technology
Record the barrel manufacturer, exact series, existing part reference and whether the proposed bit is PDC, hot-pressed diamond or electroplated. The same nominal series on two pages is not evidence that their crowns and connections are identical.
2. Record each diameter separately
| Measurement | What to identify |
|---|---|
| Bit outside diameter | The cutting gauge defining the hole at the bit. |
| Crown opening | The opening through the annular cutting crown. |
| Required core diameter | The sample dimension needed by the project. |
| Barrel dimensions | Inner and outer tube dimensions and clearances in the assembly drawing. |
The FSDRILL catalogue reference for the dual-tube PDC family lists a 94 mm product and an 89 mm core barrel. The 89 mm barrel reference is not a stated core diameter. Keep those fields separate when preparing the assembly specification.
3. Check the connection drawing
Send the thread designation, gender, pitch or lead as applicable, shoulder and seating dimensions, and the mating barrel reference. A connection photograph is useful for identification; a dimensioned drawing establishes the interface to be checked. State the drawing revision on the quotation and order.
4. Identify the crown and flushing arrangement
Include the crown height and profile, flushing channels or ports and the intended water, mud or air arrangement. The catalogue distinguishes conventional and bottom-jet hot-pressed configurations. Confirm the selected version rather than transferring dimensions or operating conditions from another crown.
5. Describe the ground and equipment
Describe the formation and changes within the hole, abrasiveness or fracturing observed on site, target depth and sample requirements. Supply the rig model, available rotation and feed controls and flushing capacity. Keep project operating settings with their specific tool and conditions.
6. State the supply and acceptance scope
List the bit, barrel or additional components required, quantity by configuration, material or inspection documents, and acceptance dimensions. Identify whether an existing sample is a reference for geometry or a part to be replicated. Confirm the final configuration before treating similarly named products as substitutes.
Compare core-bit families · Choose a cutting technology · Send the completed specification