Hole Saw Pilot Tip Segmentation for Drilling Accuracy

Solution Overview

Problem

Hole saws often experience skipping or walking during drilling, particularly in metal, resulting in inefficiencies and increased time spent drilling pilot holes, with two-thirds of the time dedicated to pilot hole creation and only one-third for actual hole drilling.

Innovation Solution

A hole saw design featuring a twist drill bit with a pilot tip and a cup-shaped member with a skirt, including a first and second cutting edge of different diameters, where the pilot tip rapidly enters the workpiece to prevent skipping and enhance drilling speed, coupled with a helical flute for efficient cutting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional drill bit is used to create a pilot hole, then the pilot hole can be drilled, but the drill bit skips or walks on the workpiece surface, resulting in poor positioning accuracy and increased drilling time

Engineering Contradiction:

Improvehole positioning accuracyVSAvoidpilot hole drilling time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The drill bit is segmented into two distinct cutting edges: a first cutting edge (pilot tip) with a smaller diameter designed to quickly penetrate the workpiece surface and establish accurate positioning, and a second cutting edge with a larger diameter that completes the pilot hole. This segmentation allows each cutting edge to perform its specialized function, eliminating skipping and walking while reducing overall drilling time

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first cutting edge performs the preliminary action of penetrating the workpiece surface and establishing the pilot hole position before the second cutting edge completes the hole. This preliminary action ensures accurate positioning and prevents skipping during the subsequent cutting operation

Inventive Principle:

Principle #10Preliminary action

2Productivity

If a conventional drill bit is used, then the drilling operation can be performed, but two-thirds of the time is spent drilling the pilot hole while only one-third is used for actual hole drilling

Engineering Contradiction:

Improveoverall hole drilling speedVSAvoidpilot hole drilling time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The drill bit is segmented into two distinct cutting edges: a first cutting edge (pilot tip) with a smaller diameter designed to quickly penetrate the workpiece surface and establish accurate positioning, and a second cutting edge with a larger diameter that completes the pilot hole. This segmentation allows each cutting edge to perform its specialized function, eliminating skipping and walking while reducing overall drilling time

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first cutting edge performs a partial cutting action by creating an initial penetration point, which is sufficient to prevent skipping and guide the second cutting edge. This partial action significantly reduces the time required for the complete pilot hole drilling operation

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS7556459B2Hole saw having a drill bit with a pilot tip

Publication Date: 2009.07.07 BLACK & DECKER CORP

AI summary

A hole saw has an arbor and a cup shaped cutting member. The cup shaped cutting member has an annular skirt with a plurality of teeth at its free end. A drill bit is secured on the arbor. The drill bit includes a pilot point with a first cutting edge. A second edge is formed on the body portion of the drill bit to form a constant diameter hole in the workpiece.