Diamond core drilling bits

The bond hardness must be inversely proportional to the hardness of the material being drilled. For hard, non-abrasive rock (like granite), choose a soft bond to ensure new diamonds are exposed quickly. For soft, abrasive materials (like sandstone or green concrete), a hard bond is essential to prevent the matrix from wearing away prematurely. Using the wrong bond can lead to segment glazing or extremely short tool life.

Buyers must verify the thread connection type, commonly 1-1/4" UNC for large rigs or 1/2" BSP for handheld drills. Additionally, confirm the effective drilling length (standard is often 350mm-450mm) and the segment height (typically 10mm-12mm). Higher segments generally offer a longer service life, provided the diamond concentration is consistent.

Laser-welded bits offer the highest safety margin and are mandatory for dry drilling applications, as they can withstand extreme heat without segment loss. Silver-brazed (high-frequency welded) bits are more cost-effective but must be used with water cooling to prevent the solder from melting, which could cause the segments to detach and pose a safety risk.

Prioritize suppliers who hold ISO 9001 for quality management and EN13236 safety certification for superabrasive products. For the European market, oSa (Organization for the Safety of Abrasives) certification is a premium indicator of high safety standards and rigorous testing protocols.

Request a pre-shipment inspection (PSI) and ask the supplier for a technical data sheet specifying the diamond grit size and concentration (e.g., 25% or 30%). For large orders, it is advisable to use Made-in-China.com's Secured Trading Service to ensure payment is only released after quality verification.

Focus on Total Cost of Ownership (TCO) rather than just the unit price. Negotiate for tiered pricing where the unit cost drops by 10-15% for full container loads (FCL). If you are a first-time buyer, request a sample kit at a discounted rate to test performance on local substrates before committing to a high MOQ.

Diamond bits are heavy and susceptible to rust. Ensure the supplier uses anti-rust oil coating and individual plastic tube packaging. For sea freight, specify palletization with shrink-wrap to prevent movement and moisture damage during transit. Ensure the HS Code (typically 8207.50) is correctly declared to avoid customs delays.

If you are sourcing OEM/Private Label products, ensure you provide a Trademark Authorization Letter to the supplier. Verify that the supplier is not infringing on patented segment shapes (e.g., roof-top or turbo shapes) held by international brands to avoid seizure by customs in the destination country.