Drill Bit Sets

[etpm]

One thing to ignore when buying cheap drill bits or actually cheap cutting tools of any kind is the "titanium" coating. The gold colored coating is titanium nitride. When it is thick enough it does truly make the tools cut easier and last longer. But the cheap tools only have a cosmetic coating which is essentially useless. The properly applied coatings used these days are usually comprised of more than one layer and different different combinations of coatings. This is because of the different metals or materials and/or conditions the tool is being used to cut. But for general purpose drilling cobalt bits last the longest and are worth the extra cost. As an addendum to the cutting oil recommendation I should add that when drilling aluminum the cutting oil can be thinned with kerosene, lamp oil, or diesel fuel at a ratio of 20% cutting oil to 80% kerosene. And if drilling pure copper, which is quite soft and gummy, whole milk or half and half make good cutting fluids and won't stain the copper brown like the sulfurized threading oil sold at hardware stores.
Eric

 

[badger123]

I have bought these M42 Cobalt Bits. They stay Sharp and cut steel like butter.

21 Pc Cobalt M42 Drill Bit Set 1/16" to 1/2" by 32nds DRILL HOG - - Amazon.com

21 Pc Cobalt M42 Drill Bit Set 1/16" to 1/2" by 32nds DRILL HOG - - Amazon.com

www.amazon.com

 

[barts]

I have a Bridgeport mill, a 15" lathe, and various smaller tools. What drill bits to buy depends on what you're drilling and how much of a hurry you're in... Mild steel (angle, channel, etc.) are generally easily drilled, even w/ Horror Freight drill bits if you don't spin them too fast. If you use the speeds and feeds found here: Speeds and feeds - Wikipedia and stick towards to the lower end of the recommended speeds, even those cheap drill bits will easily handle mild steel or 304 stainless. However, if you're drilling 316 stainless or alloy steels, you'll want those cobalt drill bits. I've drilled hundreds of holes w/ a single 5/8" Chicago-Latrobe drill bit in mild steel and stainless... but anchored in a drill press or mill. Hand drills are hard on drill bits; they tend to break drill bits since it's hard to hold them square, and it's easy to drill too fast w/ larger bits.

Learning to take your time, and sharpen drill bits of 1/4" and over by hand will definitely pay if you do a lot of fab work.

- Bart

 

[NWOH_Grizz]

Lots of good advice here on what bits to use (and not use). Just as important as a good bit is the way you use it. Learn how to calculate proper speed for drill size and material, and use a proper lubricant. Your drill bits will thank you.

 

[Glue Guy]

It's time to buy new metal cutting drill bits. Probably ought to get a set of fractionals, numbers, and letters to half inch.
Who makes the best drill bits? Best price? Best durability?

rScotty

Try MSC Supply. You can select "Made in the USA", cobalt, HSS, or even full carbide. If it's not made in the US it's probably crap! Cobalt is far better than HSS (high speed steel). Learn how to sharpen your own drills or get a Drill Doctor. For sizes, you really can get along pretty well with a 1/16" to 1/2" set by 64th's. Add a Silver and Deming (1'2" shank) set from 1/2" up to 3/4" by 16th's and you'll rarely need anything else. Number and Letter sets don't see much use except as certain size tap drills (ie; a #7 is the correct tap drill for a 1/4-20 thread!) or if you are doing precision machine work. Same with metric sizes! Buy a digital caliper that reads in thousandths and is convertible to metric, download a drill size conversion chart, and you'll be surprised at how close you can come to any size required!