Tapered Web Drill Bit for Handheld and Stationary Drilling
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Solution Overview
Problem
Current drill bits designed for hand held drills are unstable and fail quickly in stationary drill presses due to aggressive cutting angles and inability to dissipate heat, while those for stationary drill presses are too slow for hand held drills and brittle under lateral loads, lacking a combination that functions effectively in both applications.
Innovation Solution
A drill bit with a shanking end, a working end, and a helical flute portion featuring a tapering web and a helix length optimized for both hand held and stationary drill press use, made from high speed steel with at least 5% cobalt and coated with aluminum carbide or titanium aluminum nitride, hardened to enhance durability and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If aggressive cutting angles are used to increase cutting speed for hand held drills, then cutting speed is improved, but stability and heat dissipation capability deteriorate causing quick failure in stationary drill presses
Solution Approach 1:
The drill bit applies different web thicknesses at different locations: a thinner web at the working end for aggressive cutting and a thicker web at the shanking end for stability and heat dissipation. This local variation in geometry allows the single drill bit to satisfy both high-speed cutting requirements and structural stability requirements.
Solution Approach 2:
The tapered web design creates a dynamic balance between cutting aggressiveness and structural integrity. The varying web thickness along the length of the drill bit allows it to adapt its mechanical properties - being more aggressive at the cutting end and more stable at the shank end - enabling it to perform satisfactorily in both hand-held and stationary drill applications.
2Reliability
If less aggressive cutting angles and larger chisel edge are used to increase stability for stationary drill presses, then drill bit stability is improved, but cutting speed deteriorates making it unsuitable for hand held drills
Solution Approach 1:
The tapered web design creates local quality variations where the working end has thinner web for aggressive cutting while the shanking end has thicker web for stability. This allows the drill bit to exhibit both aggressive cutting characteristics and structural stability simultaneously in different locations.
3Speed
If high speed steel with aggressive geometry is used for hand held drills, then cutting speed is improved, but heat dissipation capability deteriorates causing quick failure in stationary drill presses
Solution Approach 1:
The thicker web at the shanking end provides increased thermal mass and heat dissipation capability, while the thinner web at the working end maintains aggressive cutting geometry. This local differentiation allows the drill bit to handle heat effectively in stationary drill applications while maintaining cutting speed in hand-held applications.
4Temperature
If drill bit material is made brittle to enhance heat dissipation for stationary drill presses, then heat dissipation capability is improved, but lateral load resistance deteriorates causing failure under lateral loads
Solution Approach 1:
The tapered web design places the heat dissipation function at the shanking end with thicker web section, while maintaining structural strength at critical locations. The high speed steel material combined with the optimized web geometry provides both heat dissipation capability and resistance to lateral loads.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The drill bit achieves satisfactory performance in both hand held and stationary drilling applications, capable of drilling a large number of holes without failure, exceeding the performance of existing 'Best of Class' drill bits in speed and longevity tests.
Implementation Method 1
the material used for their manufacturing is brittle. Accordingly, lateral loads applied to these drill bits cause failure. Thus, since the design factors for drill bits used in stationary drill presses is diametrically opposite to drill bits used in hand held drills, the technologies have not been combined to provide a drill bit that functions satisfactorily in both hand held drilling applications as well as in stationary drill press applications.
Implementation Method 2
The drill bit may be vapor vacuum coated including a layer of aluminum carbide, titanium aluminum nitride or combinations thereof.
Implementation Method 3
The drill bit is hardened at a temperature between 1160° to 190° C.
Data Source
AI summary
A combination drill bit for use in both hand held drills and stationary drill presses has a shanking end, a working end and a helical flute portion between the shanking and working ends. The helical portion has a helix length (L) ofL=(D×πtanα).The drill bit has a core that is tapered from the working end to the shanking end. A web thickness length at the working end is 10% to 35% of the diameter and the thickness length at the junction of the shanking end is 70% to 90% of the diameter. The drill bit is manufactured from a high speed steel including at least 5% by weight of cobalt.