High speed are used for soft stuff like plastic. They last a while on metal.
Colbalt and black oxide and titanium are supposed to last longer than high speed.
Carbide are for masonry, ceramic, glass, etc.
I'm not sure an indsutrial is any better. My problem is that most drill assortments take up a couple dozen cubic inches of air space around a dozen or so drill bits. They used to sell drill bits in a flat case that I really liked.
HSS are good enough for most home uses.
A Black Oxide drill is just a coating that makes the original drill lasts a little longer than HSS, but the drill loses its benefit once the coating is gone.
Cobalt last much longer
Titanium coated drills are for very hard steels but once the coating wears you lose the benefits.
Carbide drills made for metal are for extremely hard materials but chip with interrupted cuts. Hard to sharpen. Must use a diamond wheel for sharpening.
**************** HSS and Cobalt can be sharpened easily without losing any quality. This can be done by hand with a little practice. You can buy a drill gauge to lay the drill against and check your work.
Don't worry. They'll turn up. Or they won't.
Steve
Ebay is simply a tool which gives results dependent on the expertise of the user and how well they read the manual. It's not a "friend". In fact, without excercising care and RTFM it's one of the easiest places there is to get screwed.
Twayne
Life is like that in general, is it not? No matter where you go and what you do, your results depend on your expertise, and if you are not cautious you can easily end up screwed.
Speak for yourself if you wish, but eBay is my friend, and with a little care and experience, it can be the friend of the OP. It it is a good place to find drill bits.
I usually lose or break them before they wear out except for paddle bits...I have worn them out...Never thought about sharpening them though I just replace them.....How do you do those ???
I just use paddle bits to drill a raggedy hole. That's about all I can get from them. I have never tried to sharpen one, but I guess it could be done with a small wheel on a Foredom, Dremel, or even a Makita die grinder. If I need a decent hole, I use a Forstner, and I have gotten a lot of those at garage sales. If I had to buy them new, I wouldn't. Some of these are so old, I have to cut off the faceted end to get them to chuck up.
Steve
I was drilling 3/4 and 1 inch holes through 150 year old petrified 4X4's in my dads house for plumbing and heat(copper pipe)....After a while they just start burning their way through...Boy did that old wood stink when they started smoking...Went through a few...LOL...
I use a mill bastard "flat file" to sharpen paddle bits or any other bit I'm using out on a job. Of course a drill sharpener or bench grinder used with appropriate skill is much better for sharpening twist drills.
TDD
Hmm, Define friend. I use eBay a lot but it is not a friend.
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