Drill Bit Tech

[JOES66FURY]

Been doing a lot of work around the house and in the garage. Been building crap out of metal and wood. I also scored a nice drill press from the Goodwill down the street for a song. Been using a set of Craftsman bits for a while but, most if not all the bits are dull or worse.

So, I've been reading about different types of bits, HHS, Cobalt, Titanium etc.

I've read that Norseman HHS are quite good but, I am not in a financial position to pay 130 bucks for a set of bits right now. Other sets of HHS go for much more but, for my purposes, do I need HHS? Should I invest in 2 sets? One wood one metal? What do you guys do/use?

[TheSilverBuick]

I'm interested to hear other's thoughts.

I typically buy a new set of bits every Black Friday and throw out most the old ones. Keep the semi-commonly used ones that may still be good, like 1/8" and 3/16". But the 3/8ths and 1/4's typically just get thrown out with the uncommonly used ones. I gave up hoarding them a while ago. I bought a drill doctor but have only had marginal luck with the new sharp edge keeping its edge in the long run. I use WD-40 as the drill lube, maybe switch up to something else?

[JOES66FURY]

I'm interested to hear other's thoughts.
I use WD-40 as the drill lube, maybe switch up to something else?

A couple threads I read on a machinists forum said WD40 is a no-no, which, is one of the reasons I have WD-40 around so...CRC makes a cutting oil that I will try to find. CRC was recommended by a few users on that forum. Home Depot carries gallon jugs of cutting oil as well but, I cant see myself using a gallon of it withing the next 10 years....

[Loren]

HSS ("high-speed" steel) with the gold titanium-nitride coating works well for everything up to very-hard materials if you keep them cool, including in wood. In metal use some-type coolant from a squirt bottle, with wood just keep withdrawing the bit so as to not let it load up. I hate to buy Harbor Freight Chinese tools but frankly some of what the local hardware store has sold me for big prices has been such crap that I'll make an exception and suggest this:

I wound up with such a set a couple years ago and they've been living with my expensive USA-made bits and working just as well ever since. Being Harbor Freight that does not mean my experience will be same for everyone 'cause they do get their stuff from wherever and sometimes from mfr.'s reject bins, but it's a way to bet. The black-oxide coated drills are cheaper (by $15 in this case) but they seem to pick out better product to do the TiN coating on, all the really awful bits I've ever bought happened to be black-oxide only for some reason. I was given a giant set of bits with a well-known name brand on them for Christmas a couple years ago and man, they shouldn't have...the worst thing ever. They all wound up in a box on the shelf so they wouldn't get mixed in with the others and could just as well go in the trash. The small indexes such as fractional-sizes only are of-course cheaper.

Very high quality bits are a must in industrial situations but are best used in very high quality machines. Banging around in the workshop with a drill press and hand drills, it's better to just use cheaper ones and if you fry one here-and-there, no big loss.

Another place to score bits is CraigsList or yard sales when someone is selling a trayfull of old misc. that grandpa had. Almost impossible to keep organized though, and you'll probably have to sharpen half of them. It works to have two "sets" of bits, one set such as above that are all organized and you keep nice, and a tray full of old thrashers you just pick out of for odd use.

Sharpening bits by hand is not difficult when you understand the cutting edge they need to have. You won't attain the precision of machine sharpening but will still get the holes cut.

Re: cutting fluid, Tap-Matic from an industrial supplier is great, pipe-threading oil in a little can from the hardware store works OK, WD-40 works OK when there's nothing else within reach and is much better than nothing. "Flood" the hole, using only a tiny bit, when withdrawing the bit from the hole (called "pecking") and it will suck the fluid in. When you're making deeper or bigger holes in steel and need cooling, a pint of soluable oil from the NAPA store mixed with water as recommended and used from one of those squirt bottles they sell for WD-40 or a "chemically-resistant" bottle works well, keep the bit just cool enough that it's not making steam when you add the next shot.

Ever drilling in stainless steel? There'd be a specific set of advise/warnings for that. I won't bother here.

Love a drill press! Must-have.

[Russell]

There was a good discussion a while back about drill bits that talked about the angles of bits and why some were good and most were junk. I like to use ATF as cutting oil. I have a bunch of it that came out of a 5 speed with very few miles

[squirrel]

used to be the pipe thread cutting oil you'd get from Ace hardware was good stuff, but the modern formula is lacking...I ran out of the good stuff. I make do with the crappy stuff. I need to go shopping again, I guess.

I have a set of US made black jobber length drill bits that was kind of expensive, they are holding up well, and I do my best to take care of them. Cheap bits are cheap. If they have fancy grinding on the tip, or are gold colored, I don't really like them...good old US made quality bits like they've been making for decades, work best, for me.

Tap Magic...I have some for aluminum, but not for steel.

[Loren]

the modern formula is lacking..

Guys used to add a little carbon tetrachloride to cutting fluid, or use it straight-up. That may be one of the differences...I don't know. Uses and health/environmental hazards in Wikipedia.

[Deaf Bob]

We buy small packets of the sizes we use alot of.. Better in the long run.. We use lots of 5/16-3/8-1/2-3/4 and 1 inch.
Have a couple drill presses but like using the mag drill better..
I free hand sharpen all out bits.. We only chuck them if they break..
I like the ones with 3 flat spots on the shank.. Easier on my hands to tighten..
Have 3-4 partial bit boxes.. Cheapos get used in wood..

[anotheridiot]

I was told a long time ago, you do not use something (wd-40) or any lubricant that is supposed to reduce cutting and scoring to try to cut.

Bottom line, any steel, go for cobalt. Real cobalt. There are a ton of cobalt coated HSS drills out there, but real cobalt are the balls for cutting metal. Actually, Amazon is pretty damn good on prices if you are doing odd sizes. Got a pack of irwin cobalt #7 bits for the 1/4-20 I am constantly breaking in parts and I have used one over the past year.

I also got a pack of those step drills from one of the online places, said they were cobalt, but when they got here they were in a cute aluminum case and said cobalt coated. I would still choose that over that titanium coating from the harbor freight stuff, but when you really want to cut metal, drill thru hardened bolts that break off, I love cobalt.

[Deaf Bob]

We buy small packets of the sizes we use alot of.. Better in the long run.. We use lots of 5/16-3/8-1/2-3/4 and 1 inch.
Have a couple drill presses but like using the mag drill better..
I free hand sharpen all out bits.. We only chuck them if they break..
I like the ones with 3 flat spots on the shank.. Easier on my hands to tighten..
Have 3-4 partial bit boxes.. Cheapos get used in wood..

Yes..WD-40 is considered a no-no for drilling .
In the steel shop with punches that poke holes 1-1/4 in 1 inch plate..I talked them into using WD-40 onthe gang punches.. 8-12 holes per spray and not too messy but the iron worker got some thick motor oil like stuff.. Drill press got soluable oil.. 1qt oil to 5 gallons water..

At home I use cutting fluid for all thick drilling. Especially aluminum.. WD in a pinch but try not to..
Marvel Mystery oil or Atf with a bit of diesel.. Diesel is an oil, very thin one..

[Loren]

I've never used cobalt drill bits but then I rarely do what I'd call heavy work or drill into bolts etc. Using 5% cobalt bits on the lathe sometimes to good effect, I'd imagine it's worth the higher cost for tougher jobs.

WD-40 is good for punching, reduces material transfer onto the punch and "stripping" (pulling the punch out of the hole) is easier. A turret-punch shop I worked in, punching perhaps a few-million holes a year, used ATF applied with a paint roller when I was there, maybe they still do. Neither compound optimum for machining (as opposed to punching) I'm sure but again, by preventing galling and soaking heat away it's better than nothing. For me, the worst aspect of using the WD-40 is getting it back off if there's painting to be done. A body/paint shop I worked with wouldn't allow a can of the stuff in the shop, period, due to silicone fish-eye problems showing up in their finishing when it was around being used for corroded fastener removal and such.

I do shearing sometimes on electro-galvanized hot-roll sheet; using oil, WD-40 or any cutting fluid to forestall the galling problem creates a cleanup hassle due to how the plating seems to suck it in, which will create a paint adhesion problem for the customer. After some experimentation, what I found helps is...Windex. As long as it's wet on the metal, the blades run smooth, then it evaporates. I've seen other instances where soap works on metal also. I'm sure there is some residue left but cleanup amounts to a quick rinse. There is also something called vanishing oil but it's generally just a very light mix of oil (still) in solvent, it's the oil that does the work and the oil stays after the solvent evaporates. Fine for preventing rust but if the part is to be painted, no oil can be there.

[anotheridiot]

Yes..WD-40 is considered a no-no for drilling .
In the steel shop with punches that poke holes 1-1/4 in 1 inch plate..I talked them into using WD-40 onthe gang punches.. 8-12 holes per spray and not too messy but the iron worker got some thick motor oil like stuff.. Drill press got soluable oil.. 1qt oil to 5 gallons water..

At home I use cutting fluid for all thick drilling. Especially aluminum.. WD in a pinch but try not to..
Marvel Mystery oil or Atf with a bit of diesel.. Diesel is an oil, very thin one..

even bar soap is good for aluminum, like on cutoff wheels.

[Deaf Bob]

even bar soap is good for aluminum, like on cutoff wheels.

Candle wax on cut off blades for aluminum keeps them from clogging

[JOES66FURY]

Okay, so cliff notes

-Buy crappy bits for "honey'do's"
-Buy quality cobalt (not coated) bits for the real stuff.

WD40 is not good for cutting. A whole bunch of other stuff may or may not be, some used to be but is'nt anymore...

Copy all!

I think I will save my nickles and dimes and get a good set of cobalt bits...Time to go shopping.

Thanks for the input Gents!

[squirrel]

If you can find quality HSS bits for less money than cobalt bits, buy them. They work fine for normal drilling. I guess if you like to abuse drill bits, then cobalt may be the way to go?