Drill bits - what do you buy ?

[American Locomotive]

Going to vote Norseman here, too. I bought a set and they are great bits. I will say they are extremely sharp out of the box. So sharp you really need to be careful when drilling through steel with a powerful drill on the largest bits.

 

[Oh_Snap]

I'm just a DIY guy. I don't have the time or the talent to sharpen drill bits. 1/8" and 1/4" are "disposable". When you into Silver and Deming bits ( >1/2") they are getting pricey !

So I need to enlarge a 1/2" hole to 5/8" in a 1" thick piece of steel. Shouldn't be a problem, right ? Brand new (Chinese) black oxide S&D bit. About 1/2 way through it just stopped cutting !. I was trying to use a slow speed and not excessive pressure, but the bit is DEAD !

Drill Hog sells M7 "Hi-Molybdenum" bits and M42 "Cobalt" bits. They also come with a lifetime warranty.

So are the M42 bits worth the extra money ?

I bought Irwin's Hanson's USA Cobalt set --- the higher end Jobber ones, and I also ended up with one of their titanium coated sets.

Both the big sets of 29 pieces.

Ended up being pretty terrible drills in general.

The real hell is the replacements. They would break, and instead of sending me 1, or 2 drills ... they'd send me out another entire 29 piece set.

Now I have like six of these sets of drill bits that drive me nuts, but what's the point of buying more drills when I have a bazillion of these drills?

 

[Ilikeike]

I bought some Cle-Line mechanic length.

I use beater De-Walt jobber bits for thrash and trash jobs.

 

[NWOhioChevyGuy]

We have a few tapered reamers in the shop, used frequently when working on large truck and tractor frames. (Yes MUCH thinner material)
Brother In Law is a Semi Driver, farm shop etc.

 

[neophyte]

I bought Irwin's Hanson's USA Cobalt set --- the higher end Jobber ones, and I also ended up with one of their titanium coated sets.

Both the big sets of 29 pieces.

Ended up being pretty terrible drills in general.

The real hell is the replacements. They would break, and instead of sending me 1, or 2 drills ... they'd send me out another entire 29 piece set.

Now I have like six of these sets of drill bits that drive me nuts, but what's the point of buying more drills when I have a bazillion of these drills?

The information varies, but Cobalt bits likely work better at higher speeds, preferably in a drill press.
Cobalt high speeds steels handle heat well, do the heat isn’t really an issue with higher drilling speeds.
Cobalt steel is more brittle than regular high speed steel, or the High Molybdenum steel used in the Norseman/Viking Magnum drill bits.
This is the reason higher drilling speeds are recommended, because the drill bit will take less material per revolution at the higher speed.

Maybe there is some other issue with the bits, but if you have a bunch of extras, test it with a size you don’t use from an incomplete set.
Also, if you need single drill bits, check eBay, or see if a local Grainger will get the bits in for you.
An Irwin Hanson bit is likely yo be one of the standard readily available bit designs.

 

[Oh_Snap]

The information varies, but Cobalt bits likely work better at higher speeds, preferably in a drill press.
Cobalt high speeds steels handle heat well, do the heat isn’t really an issue with higher drilling speeds.
Cobalt steel is more brittle than regular high speed steel, or the High Molybdenum steel used in the Norseman/Viking Magnum drill bits.
This is the reason higher drilling speeds are recommended, because the drill bit will take less material per revolution at the higher speed.

Maybe there is some other issue with the bits, but if you have a bunch of extras, test it with a size you don’t use from an incomplete set.
Also, if you need single drill bits, check eBay, or see if a local Grainger will get the bits in for you.
An Irwin Hanson bit is likely yo be one of the standard readily available bit designs.

The largest issue with them is that they simply don't drill. It's as if they aren't sharp. Not for drywall, or wood, obviously, but aircraft grade aluminum, etc.

 

[2ndGearRubber]

The information varies, but Cobalt bits likely work better at higher speeds, preferably in a drill press.
Cobalt high speeds steels handle heat well, do the heat isn’t really an issue with higher drilling speeds.
Cobalt steel is more brittle than regular high speed steel, or the High Molybdenum steel used in the Norseman/Viking Magnum drill bits.
This is the reason higher drilling speeds are recommended, because the drill bit will take less material per revolution at the higher speed.

Maybe there is some other issue with the bits, but if you have a bunch of extras, test it with a size you don’t use from an incomplete set.
Also, if you need single drill bits, check eBay, or see if a local Grainger will get the bits in for you.
An Irwin Hanson bit is likely yo be one of the standard readily available bit designs.

Side note- why does the bit take less material off as rpm rises?

Is this a function of torque loss of the machine as rpm is required to rise? Thus feed pressure has to be lower? Or a fundamental factor I'm not considering in how the bit cuts?

 

[Hohn]

Enlarging a hole from 1/2 to 5/8 in a 1" thick piece of steel is nuts. You're cutting all with the flutes, not the center of the bit. For a thinner material I'd say use a step bit. For that thickness, no "regular" drill bit is going to work well, even in a drill press. I'd be looking to hog it out with a carbide burr if you can deal with a very sloppy fit. You could try a 1" step bit, but that's going to struggle immensely. I'd buy some quality cutting oil. LOL

Sounds like OP needs a reamer or 3 and some Tap Magic.
I find that a lot of times people blame the drill bit when their own technique is contributing to the failure. They are often drilling dry and way too fast, burn up the bit, then get mad at the "junk drill bit."

At least that was me until I learned. I might be the only one that obtuse, however.

 

[Hohn]

For Machine tooling, of any kind, my general preferences are 1) Swiss or German 2) USA 3) Taiwanese.

Walter makes some pretty good stuff if you can find them. They're like the A team of drill bits. But I also don't spend the money for premium on the small ones that I'll likely break anyway.
For those, I just buy decent Taiwanese or Japanese. The Hitachi set I bought is pretty decent for the money, I was surprised. Not sure where it was made.

Our local Lowe's sells Cle-Line, which was baffling to me. Did SBD buy Cle-line too? LOL!

 

[mogandave]

I like "Triumph Twist Drill", but if I only had one hole to drill and got halfway through with a cheap, sh*t-grade bit, I would just buy another cheap, sh*t-grade bit and get the rest of the way through.

For the "disposable" sizes I buy the Triumph "Thuderbits" in the multi-packs.

 

[RoninB4]

This is the reason higher drilling speeds are recommended, because the drill bit will take less material per revolution at the higher speed.

-Care to elaborate on how this is possible at a constant IPR feed rate?

 

[bb29510]

i threw my pos drill doctor away and learn how to sharpen on a bench grinder, I can sharpen a drill bit in less than three second. most time they just need a touch up

 

[neophyte]

Side note- why does the bit take less material off as rpm rises?

Is this a function of torque loss of the machine as rpm is required to rise? Thus feed pressure has to be lower? Or a fundamental factor I'm not considering in how the bit cuts?

-Care to elaborate on how this is possible at a constant IPR feed rate?

It depends on if you are plunging the drill press by hand or whether it is automatic, and geared to the chuck speed.
If the plunge rate is geared to the chuck speed, and done automatically, change the plunge rate, or buy different drill bits.

Higher rpm means the bits will grab less material if you lower the drill press at the same speed, putting less stress on the bit.
This is similar to the reason European router buts have an anti-kickback design.
The router bits have a shoulder that limits the amount of material that can be removed with each revolution of the router bit.
This limit reduces kickback from the router bit by preventing to fast a feed rate.
This doesn’t seem to be possible with smaller drill bits. (It also isn’t found on smaller diameter router bits)
Router bits also usually are run at a way higher speed than drill bits (usually 8,000-30,000rpm)

 

[RTM]

here is a brief description of what he's talking about on router bits. There is a chunk of metal preventing too deep a bite.

Benefits of Anti-Kickback and BG Test Router Bits

toolstoday.com

 

[Jim greengo]

The better dewalt bits for metal,Irwin self feed bits mostly for wood.
I do have a set of while Bosch spade bits that are supposed to be nail eater.

 

[clutch47]

In the OPs case, I'd go slow with lubricant and steady pressure.
I swear by these bits..
http://wintersdrillbitcity.com/

 

[RoninB4]

It depends on if you are plunging the drill press by hand or whether it is automatic, and geared to the chuck speed.
If the plunge rate is geared to the chuck speed, and done automatically, change the plunge rate, or buy different drill bits.

-Your recent post is different than the previous flat statement claiming
"This is the reason higher drilling speeds are recommended, because the drill bit will take less material per revolution at the higher speed."
-Higher RPM is supported by the drill material, not necessarily recommended. Cutting speed largely depends upon the material being cut as well as what the cutting tool itself is made of. Speed in RPM doesn't affect the amount of material being cut, the feed rate into the material does.

Higher rpm means the bits will grab less material if you lower the drill press at the same speed, putting less stress on the bit.

-Gee no kidding. Same feed rate at higher RPM cuts less material is a change in IPR (Inch Per Revolution). This is a more valid explanation than the first statement that increasing RPM alone will cut less material. Feed rate is also expressed as chip loading per tooth and a different, but related, topic for another time.

This is similar to the reason European router buts have an anti-kickback design.

-Using router bits and drilling are not the same subtractive processes, even in plunge routing. The flute geometry, cutter material, and material being cut (if it's not metal) are nowhere near the same. The "anti-kickback" you reference limits the feed, not speed.

the heat isn’t really an issue with higher drilling speeds

-This is a blatantly false statement, heat has a LOT to do with what occurs with almost all machine cutting methods. Speed generated heat, abrasion, and material (being cut) properties are what dull a cutting tool. Does work hardening mean anything to you?

-You're entitled to believe what you want but several of your posted statements are either misleading or just flat out wrong. This is not a personal attack on the OP. For those wanting to learn I would suggest not blindly accepting what either of us post, do your own research and decide for yourself. I've only been a professional toolmaker for 30+ years so what would I know?

 

[neophyte]

-Your recent post is different than the previous flat statement claiming
"This is the reason higher drilling speeds are recommended, because the drill bit will take less material per revolution at the higher speed."
-Higher RPM is supported by the drill material, not necessarily recommended. Cutting speed largely depends upon the material being cut as well as what the cutting tool itself is made of. Speed in RPM doesn't affect the amount of material being cut, the feed rate into the material does.

-Gee no kidding. Same feed rate at higher RPM cuts less material is a change in IPR (Inch Per Revolution). This is a more valid explanation than the first statement that increasing RPM alone will cut less material. Feed rate is also expressed as chip loading per tooth and a different, but related, topic for another time.

-Using router bits and drilling are not the same subtractive processes, even in plunge routing. The flute geometry, cutter material, and material being cut (if it's not metal) are nowhere near the same. The "anti-kickback" you reference limits the feed, not speed.


-This is a blatantly false statement, heat has a LOT to do with what occurs with almost all machine cutting methods. Speed generated heat, abrasion, and material (being cut) properties are what dull a cutting tool. Does work hardening mean anything to you?

-You're entitled to believe what you want but several of your posted statements are either misleading or just flat out wrong. This is not a personal attack on the OP. For those wanting to learn I would suggest not blindly accepting what either of us post, do your own research and decide for yourself. I've only been a professional toolmaker for 30+ years so what would I know?

Higher speed does usually result in less material removal per revolution.
Most people don’t jam the bit into the workpiece as hard and quickly as possible when manually plunging a drill press (some do, most don’t).
The higher drill speed will therefore result in a thinner chip or shaving, which will torque the drill bit less.
For drill bits with a harder more brittle alloy, like Cobalt Steel, this may be important to prevent drill bit breakage, and similarly for solid carbide drill bits.
The major issues with drilling steel and certain alloys with slow drilling is if the metal may work harden.
Other than higher hardness the addition of Cobalt adds to High Speed Steels, the advantage is increased heat resistance while maintaining hardness.