Drill bits

[ldj]

Are titaniun nitride coated bits worth the extra cost? I have heard they are the same as the M2 high speed steel except with the coating. Wouldn't that coating ware off or at least be gone with 1st sharpening?

 

[Christopher S.]

My Personal Favorite are cobalt bits, try here.
click here

 

[TimV]

As a rule, drill bit coatings are a great way to charge $2.00 for a $.50 bit with $0.01 of coating on it. In some cases (highly abrasive materials, for one, hand tapping for another), they can help either decrease wear or ease friction, but in most they're not worth the cost. A quality uncoated bit will outperform and outlast a cheap coated one every time.

 

[Gun guru]

True.
If you buy the high quality bits (made in USA) then it doesnt matter if they have the TiN coating or not. TiN coating works best on milling cutters and carbide inserts for lathe bits and shell milling cutters.

If you are drilling into hardened material then buy M42 drill bits or get carbide drill bits, just run with a slower speed and use lots of oil for lube and cooling.

 

[Eric in IL]

Question 1: Probably not if you are doing farm shop type work. Maybe, if you are doing repetitive controlled feed work on something tough like some of the stainless steel varieties.

Question 2: Sharpening a roughing end mill will remove the TiN coating from the cutting surface. The coating on the cutting surface of a drill will still be intact after sharpening. The tip that you grind when sharpening should not contact the metal you are drilling.

TiN coating is applied to poor quality drills as well as high quality drills. Buyer beware.

 

[MarkB_MI]

Cobalt is mo' betta. I've seen some very crappy gold-colored drills.

 

[NCWayne]

Please explain your answer to number 2. I've sharpened alot of drill bits over the years and can't for the life of me figure out what part of the bit your sharpening that doesn't touch the metal when drilling. The cutting edge getting dull from contacting the metal is the very reason you have to sharpen the bit. In other words, no other area on a drill bit does any cutting but the cutting edge at the end of the bit that has to be ground to sharpen, so I'm really curious as to what you mean.....

 

[Eric in IL]

I guess my answer to #2 was somewhat misleading. There is a small portion of the drill tip that will contact the work. It is at the center of the bit, or web of the drill. The rest of the contact area is at the cutting edge, which I do not call the bottom of the bit. As the bit becomes dull you do have contact or rubbing at the bottom of the bit.

The point I was trying to make was that sharpening and consequently removing the TiN coating on the bottom of a drill bit should have very little effect on the intended purpose of the coating.

Sorry for the confusion.

 

[Fred Martin]

Chris, I guess if I was coaching a farmer on what type of twist drill to buy, I wouldn't advise him to buy cobalt. Yep. they're a lot harder and will drill more holes than high speed...BUT, a lot of the farmers work is with a hand drill and in my opinion their too brittle and break too easily unless you have a drill press or a vertical milling machine. I like them too. I wouldn't advise him to use the ones with the real thick web either because to use them in a hand drill, you need to thin the web at the chisel point because if you look at it theres no cutting edge on the very point of the drill...it has to push it's way through the metal. And for a farmer (most of them) it's hard enough to tell them how to sharpen a dull drill. ohfred

 

[Christopher S.]

True on all accounts, thanks for your supplemental info

 

[dan osborne]

What about the Turbo-Max bits or the Black and Decker Bullit bits?

 

[Dick L]

Any thing over a 1/4" hole I always drill a pilot hole which solves all of those concerns. I thought everyone did. If you don't first drill a pilot hole ya gotta love pushing on the drill. At 73 I don't got the push I usta have. I seem to still need to drill a bunch of holes. Drilled 24 Sunday. I have never chipped a cobalt dill bit hand drilling. Chipped or broke my share of carbide for sure. Probly drill twice that many Wednesday.

 

[ohenry]

/Cobalt is the only way to go. They last longer and can be used on stainless. Coated bits seem to wear quickly if used on hard steel. Cobalts will out last all other bits by a factor of 3 or more.

 

[MarkB_MI]

Dan, I know nothing about those products. If it ain't cobalt, I don't buy it.

Cobalt drills are available at reasonable prices from The Yard.
The Yard

 

[RodinNS]

I've tried quite a few different drills including the high dollar cobalt variety. For general use, farm repair type work... I seem to keep coming back to the cheapest miserable set of HSS china crap I can buy. They all break. They all dull. They're all basically crap... so I might just as well have cheap crap.
For larger drills I most often make a point of buying Cleveland HSS and those have served me well.
I found the cobalt bits were great to drill with... the problem was that they were so hard the chuck didn't want to grip them. Some had three sided shanks to solve tht problem... and when they caught... they either broke off or bent. There's just no cheap lunch with drills... so I buy the cheap stuff and learn to sharpen them.
But to answer your question... yeah, once you sharpen the titanium off... you basically have a cheap nasty HSS bit.

Rod

 

[60 acre hillside]

Kind of like I do. I buy some odd stuff from Wholesale Tool of Oklahoma, I shapren and abuse and sharpen again

 

[RodinNS]

I was doing some cleaning here a couple months ago... I found the cases for I think six 29 piece sets and I don't have enough drills left to make ONE complete set. Probably enough to make 2 fairly full sets... then a couple more very sparse partials... including the half length stubbies that've been broken off and resharpened.

Rod

 

[Dick L]

I made the part on the right Tuesday using a Harbor Freight gold colored drill bit, a band saw and a Craftsman jig saw with a Black & Decker metal cutting blade to square the slot using the part on the left as a pattern.

 

[36 Coupe]

Sad to say Ive found some china drills that do good work.Ive been sharpening drills for over 50 years.They do get dull, no matter who makes them.