Gun Drill Oils

Gun Drill Oil for Deep Hole Drilling

Reliable gun drill oil is critical for precision deep hole drilling. It provides the lubrication, cooling, and chip evacuation needed to maintain straightness, surface finish, and tool life at extreme depth-to-diameter ratios. This category presents our three viscosity options (ISO 12, 24, 36) so you can match the oil to your drilling parameters and material.

What Gun Drill Oil Does

• Chip evacuation: Carries chips out through the flute/channel to prevent flute-packing and tool seizure.
• Friction reduction: Forms a stable film between guide pads, hole wall, and cutting edges to minimize wear.
• Heat removal: Extracts heat from the cutting zone to stabilize geometry and reduce thermal cracks.

Selecting Viscosity for Your Process

Choose viscosity based on tool diameter, spindle power, feed/speed, and depth. As a rule of thumb:

• ISO 12 (low viscosity): Best for small diameters, very deep ratios, and finishing where penetration and fast flushing are paramount. See EASYCUT NMO121.
• ISO 24 (medium): A versatile “workhorse” for mixed materials and general deep hole drilling when you need balanced lubrication and flow. See EASYCUT NMO241.
• ISO 36 (higher viscosity): Favoured for larger diameters, higher currents/loads, or aggressive roughing where a stronger film helps prevent film rupture. See EASYCUT NMO361.

Target circulation temperature typically falls in the +30 to +50 °C range. Too cold reduces flow and can increase tool stress; too hot accelerates evaporation and ageing.

Best Practices for Stable Deep Hole Drilling

• Flow & pressure: Maintain the manufacturer’s recommended flow and pressure to keep chips moving and the tool supported in the bore.
• Filtration: Use appropriate filtration media and intervals to prevent recirculating fines that erode margins and pads.
• Viscosity control: Match oil grade to diameter and depth; adjust if you see film rupture or flute-packing trends.
• Thermal control: Keep oil in its working temperature window to stabilize viscosity and reduce thermal distortion.

Common Problems and How Oil Choice Helps Prevent Them

• Excessive heat / thermal cracks: Often due to insufficient flow or pressure. A viscosity better matched to the job and proper delivery reduce heat load.