drill bits

[yamahayfz450]

whats the best brand of drill bits to buy(especially for metalworking)? i have bought drill bits from dewalt but they just break to easy. What kind do you guys use? Im looking to buy a 115pc set and dont mind spending the extra $$$$ for a good quality set. Thanks


Mike

 

[eschoendorff]

whats the best brand of drill bits to buy(especially for metalworking)? i have bought drill bits from dewalt but they just break to easy. What kind do you guys use? Im looking to buy a 115pc set and dont mind spending the extra $$$$ for a good quality set. Thanks


Mike

I have had good luck with Irwin (USA) bits. Google Magnum Super Premiums... those are good too.

 

[bmwpower]

I second Irwin. I have some of their cobalt bits and they've held up very well, but at a price.

 

[Mike F]

I recently was stuck and had to go toHD and buy a 1/4" Dewalt cobalt bit. I was very disappointed with it. I was drilling through steel angle iron, and while the split point part of the bit went through easily, the remainder of the bit did not. I had to slowly step up sizes using my Irwin HSS bits until I could get the Dewalt to punch through. To be fair, I was using an electric (corded) drill with a max speed or 1200 rpm. I am going to try the Cronatrons next, as I have heard really good things about them .

 

[Canadian Charlie]

I've never had any luck with drill bits so the cheap stuff works fine for me

 

[MXtras]

Cobalt is a good choice (it's an "ingredient" in the metal alloy, not the name brand from Lowes). Cobalt adds toughness to the steel and will hold an edge longer than plain HSS.

HSS is the minimum material for a drill - it stands for High Speed Steel and it is a grade of tool steel. Your typical, run-of-the-mill milling cutters are HSS, so it's tough material. Look for drills that state they are made from "HSS" or "cobalt" and stay away from anything that doesn't tell you what they are made from. Carbon Steel is worthless for a cutting tool unless all you plan to cut is wood and is what the cheap sets are made from - you can tell when you grind it. Sparks from HSS are short and bright white or yellow. Sparks from carbon steel are orange and long - and sometimes sparkle.

I use Titex drills available from MSC, but you won't want to pay the price I am sure - they are pretty pricey but they run very well and last a very long time.

Search this site - there are a lot of threads on this and related topics.

Welcome to the boards, by the way!

Scott

 

[Roospike]

Get the bronze looking cobalt drill bits not the shiney gold looking cobalt drill bits .

The bronze looking bits are made with cobalt , the shiney gold looking cobalt bits are an outside coating and dont last as long or stay sharp as long.

I do a lot of metal fabrication and the bronze cobalt bits will out last the gold 10x .

 

[chad s]

To be fair, I was using an electric (corded) drill with a max speed or 1200 rpm.

1200 rpm is actualy too fast for cutting through steel. You will ruin the bit that way, very quikly. Slower speeds, proper feed rate (pressure in the case of a hand drill), and cutting fluid are the keys to proper drilling through metal. Chances are, the heat buildup you got from drilling so fast ruined the bit, possible on the first hole.

I highly reccomend a drill set from Chicago Latrobe, Precision Twist, or Champion Cutting Tools.

 

[MXtras]

1200 rpm is actualy too fast for cutting through steel.....

I highly reccomend a drill set from Chicago Latrobe, Precision Twist, or Champion Cutting Tools.

Spot on, Chad.

1200 RPM in steel would be a pretty small drill. For a larger drill - say 1/2", your RPM will be around 500RPM on a machine and probably around 300 or less by hand with a small pilot hole.

Remember - if you are making noise, you are making heat and you are cooking your drill. If you are making chips, you are making a hole. When you finish driling, the drill (bit) should NOT be hot to the touch. If it is, you were either spinning to fast or not applying adequate pressure. Adjust speed and feed until you obtain long, curly or stringy chips and your drill will only be warm when you finish - the chips will carry almost all of the heat. Most of the time you will be suprised how slowly you will be spinning the drill and your drills will last for many, many years requiring only minor touch-up every once in a while. Use a Drill Doctor if you are not well versed in sharpening.

Make good chips - the hole is the by-product.

Precision Twist drills are your best bet I think.

Scott

 

[kartracer55]

whats the best brand of drill bits to buy(especially for metalworking)? i have bought drill bits from dewalt but they just break to easy. What kind do you guys use? Im looking to buy a 115pc set and dont mind spending the extra $$$$ for a good quality set. Thanks


Mike

The Dewalt bits break "easily" because of the user, not because of inferior quality. No offense or anything, I am just saying... Your using Dewalt Cobalts presumably? on a hand drill. The wobble from the drill while in a steel hole is going to snap them. I learned that lesson.

Also look for Chicago Latrobe Cobalts. These are what I buy locally and I have not had to sharpen any of them after a few years of weekly (not daily, 1-2 times a week usually) use. If your drilling by hand, go for a Coated HSS bit because they are more forgiving. Not as "brittle"

Just an opinion

Jim

 

[Mike F]

From another thread:

-lecroix-
Senior Member



Default Re: Black oxide drill bits... buy or pass?
The secret is using the correct speed and feed on ANY drill ... regardless of the coating.

Rule of thumb:

(4 * CS) / Dia. of drill = RPM

CS = Cutting Speed

CS for most common metals:

50 for most cast iron
75 for most stainless steels
100 for most carbon steels
500 for most aluminum

example for a 1/2" HSS drill in steel

(4 * 100) /.5 = 800 RPM

Hope this helps.
Last edited by -lecroix- : 02-13-2007 at 08:07 PM.

Using this formula, (4 x 75)/.25 = 1200
so that's how I arrived at the speed. I did try lower speed initially since it's a variable speed drill. Is this formula not correct or am I misinterpreting something?

 

[-lecroix-]

Machinists around the world use that formula ... whether drilling manual or programming a CNC.

 

[Jared]

i thought the 4 was if you were drilling aluminium.

jared

 

[wilbilt]

I have had good results with Triumph drills. Not real pricey or fancy, but they do the job if you respect them.

I just bought a Drill Doctor, and have sharpened a few bits so far. There is a little bit of a learning curve, but I think I have the hang of it. Using it will be much better than tossing the dull bits and buying new ones...

 

[-lecroix-]

i thought the 4 was if you were drilling aluminium.

jared

4 is a constant in this formula regardless of material ... the only number that changes is the CS ... in the case of aluminum, the CS is 500.