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Reddit mentions of Drill Hog 10 Pc Spiral Screw Extractor Left Handed Cobalt Drill Bit Set
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Reddit mentions: 1
We found 1 Reddit mentions of Drill Hog 10 Pc Spiral Screw Extractor Left Handed Cobalt Drill Bit Set. Here are the top ones.
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5 Left Handed Drill Bits Cobalt M42 Sizes: 5/64", 7/64", 5/32", 1/4", 19/64"Includes 5 Spiral Screw Extractors #1, #2, #3, #4, #5Removes Broken Bolts, Screws, and StudsLeft Hand Threads Designed for Counter Clockwise OperationLifetime Warranty
Specs:
Might want to practice on a spare bolt, especially depending on how much experience you have drilling steel.
You'll want a very sharp tip, a lot a pressure, and as slow a speed as your drill will do because you don't want to work harden the steel by heating it up. For that reason pull out and pause a lot too, and again use plenty of cutting fluid, or at least WD40 or motor oil.
If you're making powder or not cutting at all you need more pressure and/or less speed. If you're getting ribbons of metal coming out that's correct. Cobalt might be better than HSS in case you end up work hardening it a bit, but carbide will probably snap from the pressure in a hand drill because it's more brittle. Definitely use a center punch so the bit doesn't dance at the beginning.
Can maybe use a piece of tubing or just a cut up pen tube or marker body to protect the thread, and a tape wrap on the drill bit can be used to control depth.
If you can get a reverse twist drill you might be able to prevent over tightening the bolt by drilling it, or even just turn it out if it jams.
This looks like a good set with matching extractors. There are cheaper ones, but with mixed reviews due to sharpness or not actually being cobalt.
https://www.amazon.com/Drill-Hog-Spiral-Extractor-Handed/dp/B07SSCNSHP/