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US3258284A
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Drill bit and rod coupling
|
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US3258077A
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Piercing point hammer drill bit
|
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US3071201A
|
|
Piercing point rotary drill bit
|
|
US2740612A
|
|
Two-arm rotary drill bit
|
|
US2607562A
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Self-piloted rotary drill bit
|
|
US2660483A
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Percussive drift drill
|
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US2648525A
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Core-breaking drill bit for doubleflute augers
|
|
US2572280A
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Drill stock power drive coupling
|
|
US2578593A
|
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Auger-type drill bit
|
|
US2532783A
|
|
Self-piloted rotary drill bit
|
|
US2521089A
|
|
Mining machine cutter bit
|
|
US2524570A
|
|
Core drill bit
|
|
US2507221A
|
|
Single edge percussion bit
|
|
US2507222A
|
|
Multiple edge percussion bit
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