Drill Bits...

[618 Syndicate]

I worked in a machine shop like 18 years ago for a few months, it wasn't really my thing, but I did learn how to use drills and lathes properly, and how important material selection for application is.

 

[Erik the Awful]

Never used it but snap on over hear swears on the performance. Plus there lifetime warranty

I have a set of Snap-On bits I bought back when I was a tech. They're decent. "Lifetime warranty" doesn't mean as much if the Snap-On guy wants to whine and argue and be a pain in the butt whenever you try and get a tool replaced. The Harbor Freight cheapo cobalt bits I bought have worked better, but it may also be that I'm more experienced now. I buy the smaller bits in 10 packs from Amazon because they break. Just be sure and get cobalt or tungsten carbide.

 

[Erik the Awful]

Doh! I was using my drill set last night and realized I don't have cobalt bits. I have the Warrior titanium nitride set. Whatever, they cut. Then today I found Project Farm's drillbit test:

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[alpinecrick]

Brand is less important than material. For drilling hardened steel you will have better performance from tungsten carbide or cobalt bits.

This^^^
I have 2 sets of M45 (8% cobalt) bits, and any time steel is involved those are the ones I use.

 

[Schurkey]

Norseman brand.

I have a set of those. They're cut OK, except that they're thick-web, "split point" bits, and I hate thick webs and split points. Manufacturers often use thick webs to make up for using crappy steel. The steel is brittle, so without a thick web, the bit shatters easily. In other words, the thick web is a cost-cutting measure because they can cheapen the raw material.

My "good" bits are USA-made, HSS, thin-web Government-Surplus from decades ago. Properly sharpened, they cut like crazy. Sometimes, they break. And the ones that get used, are getting pretty short from resharpening.

Thick-web bits are stronger, so they take abuse better...but they're harder to push through the material. To sort-of make up for that, they sharpen them by splitting the point. Duplicating that when re-sharpening is hateful. And I've seen brand-new, factory-sharpened bits that have crappy geometry; they don't stand a chance at cutting properly.

For the record, I worked in a production environment for thirteen years. The Company sent out the dull drill bits to an outside contractor for re-sharpening. (Hundreds, if not thousands of bits at a time, and 11/64 was hugely popular.) The sharpening contractor did such a piss-poor job (Drill Doctor, or similar) that when we got the "sharpened" bits back, I'd have to put them against a bench grinder to make them cut. In other words, I could re-sharpen the bits by hand on a bench grinder and make them better than the "professionals" could resharpen them using a fixture and diamond wheels. (Dumbasses put no relief on the cutting edges, so the bit resisted going into the metal.) It got so bad that eventually the company quit resharpening bits smaller than a certain size--they just bought new ones. I've got five pounds of used, dull but otherwise OK smaller drill bits that someday I'll get around to sharpening, that I took home from that company. They were going in the dumpster otherwise.

SHI TTY CHINESE BITS ARE NEVER GOING TO CUT PROPERLY. The steel is no good. A proper sharpening gets them to cut nice...once. If the hole isn't too deep.

If you see drill bits that have a little "pilot" point on them, for Fo ok's sake don't buy them. They're a gimmick. Good luck resharpening them. They're junk drill bits with a fancy, factory-sharpened end that can't be duplicated. Use 'em once or twice, throw them in the recycle bin. Garbage.

IF (big IF) the steel is good, a drill bit can be sharpened to cut and to last...but thick webs make that a challenge. Not impossible, but not easy, either.

In my experience, drilling mild steel, broken bolts, etc--it matters less that the bits are "Titanium" coated; or Cobalt; or whatever Miracle Technology. The common stuff is made with cheap steel, thick webs and split points, and they don't work as well as a QUALITY HSS thin-web bit that's been sharpened properly with some relief on the cutting lips.




As others have said, don't sneak-up on the final hole size by drilling progressively larger. Select your final drill bit size. LOOK at the web of that bit. Select a pilot bit just a hint larger than the web. Drill the pilot hole, drill the hole "for real". Two steps--not five, or three, for any drilled hole likely found in automotive work.

 

[Hipster]

"Wurth" brand bits is the best set I have. HSS German tool steel blah, blah, blah. They've lasted a long time. Cutting fluid helps.

There all kinds of guides out there about drilling speeds, bit sizes, and base metals your drilling.

Also not a fan of Drill Doctors or miracle coatings.

Buying cheap bits is akin to buying cheap striking tools. The proper metallurgy just isn't there.

 

[Schurkey]

Buying cheap bits is akin to buying cheap striking tools. The proper metallurgy just isn't there.

...and they're dangerous.

 

[MrPink]

I use these in my home garage but when I was in a shop whether it were an autobody or mechanic shop I had Snap-on stuff. I still talk with my former snap-on guy but I haven't had to warranty a tool in a long time outside of the craftsman screw driver I broke a couple years ago and I have a 1/2" ratchet that is broken too sitting in my drawer.

Milwaukee SHOCKWAVE IMPACT DUTY Titanium Twist Drill Bit Set (23-Piece) 48-89-4631 - The Home Depot

The MILWAUKEE 23 Piece SHOCKWAVE RED HELIX Titanium Drill Bit Set is engineered for extreme durability and long life. The QUAD EDGE tip delivers a precision start and four cutting edges to create smaller

www.homedepot.com

 

[thegawd]

I broke my first cobalt drill bit yesterday. it's a 3 pointed bit and I'm sure I could properly resharpen it. I was breaking the rules and drilling in a tight spot on an angle, frustrated trying to fix my 35 year old lawnmower deck. It is an Asian product.... it shattered. anyways it broke in a way that almost seemed like it was ment to, shorter and completely usable almost like it never broke! I drilled 2 more holes with it.

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[thegawd]

Schurkey, the shattered parts off that drill bit were without a doubt little weapons. the one rule I wasnt breaking was wearing safety glasses. the shards were all little spears waiting to penetrate skin or eyeballs. I always clean up the drill bit shavings so they dont end up in someone's feet, so I was able to get a good look at them. I didn't take any pics though.

these drill bits normally work wonderfully, just remember to wear your safety glasses!