Selection, Installation, and Interfacing of Core Drill hydraulic Clamp

Technical Guide | Core Drilling

Selection, Installation, and Interfacing of Core Drill Hydraulic Clamp

JCDRILL Technical Support · Core Drilling Equipment

A JCDRILL core drilling rig; the clamp is matched to its pulling capacity and hydraulic control ports.

A wireline hydraulic clamp performs only as well as its selection, its alignment at the collar, and its connection to the rig's hydraulic circuit. Here is how to get all three right.

Selection

During the selection phase, one must look beyond mere external dimensions. First, determine the clamp body specifications based on the drill rig’s rated pulling capacity and the available installation space at the borehole collar, ensuring the unit can withstand operational loads. Second, select the slips (jaws) based on the specifications of the wireline core-drilling rods commonly used. This clamp model features interchangeable slips—supplied with standard NQ, HQ, and PQ sets—which can be swapped on-site as needed. A single clamp unit can thus accommodate various wireline drill rod sizes, eliminating the need to purchase separate clamping equipment for each rod type; this reduces equipment costs and enhances adaptability to diverse drilling conditions. As wear parts, the slips are designed for easy replacement, simplifying long-term maintenance.

Installation

During installation, maintaining coaxiality is of paramount importance. The clamp is secured via a flange at the borehole collar. When fastening, the center of the clamp’s bore must be precisely aligned with the center of rotation of the drill rig’s power head. Any eccentricity will lead to severe uneven wear on both the drill rods and the slips during drilling and extraction, while also increasing the risk of the rods becoming stuck or fracturing. The base bolts must be tightened evenly to prevent any displacement during operation. When installing the slips, ensure they are oriented correctly and operate without obstruction; perform a no-load test cycle to verify smooth movement before commencing load-bearing operations.

Clamp units packed with pre-fabricated high-pressure hoses and fittings.

Each unit ships with its clamp and release plumbing assembled.

Hydraulic Connections

Regarding the hydraulic connections, the clamp assembly comes with pre-fabricated high-pressure hoses and standard hydraulic fittings. It includes two independently controlled hydraulic circuits—one for clamping and one for releasing—which can be connected directly to the drill rig’s existing hydraulic control ports, typically requiring no major modifications to the rig’s main hydraulic system. Before connection, clean the interior of the fittings to prevent debris from entering the hydraulic system, which could cause wear to valves and cylinders. Ensure sufficient slack when routing the hoses to prevent them from being pulled or strained by the movement of the power head or vibrations from the drill rig. Once the hydraulic lines are connected, bleed the air from the circuit and adjust the operating pressure. Use the drill rig’s control handles to operate the clamp, verifying that the clamping force is sufficient to ensure a secure grip, while also confirming that the clamp releases promptly—meeting the requirements for tripping drill strings and making up or breaking out drill rods.

Routine Operation

During routine operation, follow proper handling procedures, regularly inspect hydraulic hoses and fittings for leaks, and check the slips for wear. Perform timely maintenance to extend the service life of the clamp and ensure that drilling operations remain continuous, safe, and efficient.