Drilling

What to consider when drilling convex surfaces.

Understanding the entire gundrilling system helps resolve tooling problems.

Test results show a new HSS drill can provide cost-effective performance when machining hardened plate material.

A new drill point geometry developed by a tool and cutter grinder. The through-coolant drill is ground in such a way that a hollowed out chamber on the face of the tip retains coolant in the cutting zone while hydraulic forces that are created push fluid to the cutting edge.

Gundrilling: going deep

For drilling standard holes in metal, there are three primary types of drills: twist, spade and indexable insert. This article discusses the pros and cons of each design and the applications for which each might be appropriate. Factors considered include hole depth, tool cost, drill speed, coolant delivery, tool inventory required, machine tool requirements and expected tool life.

When hole depths exceed four times the drill diameter, problems with cooling and chip evacuation can arise. This article discusses these problems and the drill geometries, machining parameters and coolant options that can minimize them. Charts are included giving speeds and feeds for various workpieces and drill diameters.

U.S. manufacturers are in a transition period, moving from inch to metric specifications. This article looks at the impact this change is having on the manufacturing and use of drills. The discussion also covers the advantages and disadvantages of going metric and the availability of metric drill sizes in the United States.

Indexable-insert drills offer several advantages for producing short holes. This article describes the drills' features, uses and benefits. Tips are provided to help select the optimal tool, insert and machine settings. A trouble-shooting chart is included.

A detailed description of a combination drill that machines six different
hole diameters. Used on a dedicated drilling machine that drills cast iron
cylinder heads, it was developed over a number of years. The six-in-one tool
is made of HSS and has carbide inserts.