Why is lubrication important when tapping or cutting?

• A. Reduces friction, heat, and wear; improves thread quality and tool life.
• B. Increases cutting speed
• C. Improves only surface finish
• D. Prevents rust on the machine bed

Answer: (A)

Lubrication is essential because cutting and tapping generate a lot of heat and friction where the tool meets the workpiece. The lubricant creates a film between the tool and metal, which reduces contact and the shear stresses that cause wear. With less friction and better heat management, the cutting edges stay sharper longer, the tool life increases, and the risk of the tap breaking decreases.

Lubrication also helps form and support the correct thread shape, so the finished threads are more accurate and consistent. It aids chip control and prevents galling or welding of metal to the tool, which further improves the surface finish indirectly and keeps the process smoother overall. While lubrication can influence surface finish and play a role in corrosion prevention in other contexts, its primary benefit during tapping and cutting is reducing friction, heat, and wear to produce better threads and longer-lasting tooling.