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Core Drill Modification

IP.com Disclosure Number: IPCOM000079295D
Original Publication Date: 1973-Jun-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Rohr, RL: AUTHOR

Abstract

When holes have to be drilled in hard materials, such as glass and the like, there are generally employed diamond core drills. When a core drill runs very true, the drilled hole size is accurate and, correspondingly, the core of hard material in the center of the drill is also accurate. Because of this phenomenon, quite often it is very difficult to remove the core of hard material from the drill. Frequently, there has to be used a low-pressure coolant for drilling and then higher pressure to expel the core. This requires a costly adjustment to coolant pressure.

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Core Drill Modification

When holes have to be drilled in hard materials, such as glass and the like, there are generally employed diamond core drills. When a core drill runs very true, the drilled hole size is accurate and, correspondingly, the core of hard material in the center of the drill is also accurate. Because of this phenomenon, quite often it is very difficult to remove the core of hard material from the drill.

Frequently, there has to be used a low-pressure coolant for drilling and then higher pressure to expel the core. This requires a costly adjustment to coolant pressure.

In the modification of a core drill described herein, the core drill with the center hole is constructed to be slightly out of concentricity with the outer diameter of the drill. Consequently, in operation, the eccentric rotation of the center hole produces a core size which is smaller than the hole and the core of hard material readily is removed or falls out of the drill.

This modification produces many beneficial results. For example, it effects a time-saving when many holes are to be drilled. It is advantageously employed when low-pressure cooling water is used to minimize drill breakout, which can cause chipping of a brittle workpiece. It also enhances cooling flow to remove debris from the cutting area.

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