Tungaloy’s DeepTri-Drill Offers New Coated Guide Pads for Eco-Friendly Machining


Iwaki, December 2019 — Tungaloy’s DeepTri-Drill line of indexable deep hole drills now includes FH3135 grade guide pads.

DeepTri-Drill is a successful line of indexable insert gun drills that provides productivity and application security for drilling deep holes, while ensuring easy tool management by eliminating the need for regrinding. The drill line now offers a new FH3135 grade guide pad that was developed specifically to enhance thermal crack resistance when machining with water emulsifiable oils.

The tribological conditions during gun drilling between the guide pad surfaces and the wall of the hole being drilled are far more severe than those during other applications. To ease this harsh condition and maximize guide pad life, it is crucial to use cutting fluids with high lubricity in order to prevent dry rubbing and seizure at the burnishing contact areas. For these reasons, straight cutting oils have long been preferred among manufacturers in gun drilling operations for its high lubricity. However, in today’s environmental conscious machining, the call for eco-friendly water emulsifiable oils, more commonly known as soluble oils, are increasing over conventional petroleum-based coolants. These soluble oils have lower lubricity than straight oils and can adversely affect the guide pad quality during gun drilling.

To meet this challenge, Tungaloy has expanded its DeepTri-Drill guide pad options to include the FH3135 grade. Guide pad rupture is primarily induced by an increase in density of thermally-induced microcracks generated on the substrate due to poor lubricity and thermal capacity when machined with soluble oils. The dedicated carbide substrate of the FH3135 guide pad provides enhanced resistance to fracture and thermal crack, significantly reducing the risk of guide pad breakages. In addition, the new guide pad features a double-chamfer geometry on the corners of both ends assisting a smooth entry into the guide bushing or pilot hole, inherent when machining on dedicated gun drilling machines.  This reduces vibrant impact on the guide pads and the risk of rupture.

  • At a Glance:
    • Guide pads with high fracture resistance for use with soluble oils
    • Dedicated carbide substrate has superior resistance to fracture and thermal cracks
    • Double-chamfer geometry allows smooth entry into a guide bushing or pilot hole
    • Total of 13 items to be added