Are coatings any help in regards to durability?

Cliff Stamp

Oct 5, 1998
While there are some coatings that are mainly for corrosion resistance like Black-T, some are thicker and much harder and claim to extend life of machining tools and the like. What I was wondering is do any of the thicker more durable coatings add to the toughness of blades by their ability to resist bending and being deformed or are they simply too thin for such large scale issues?

In my experience with the cutting tools like taps and drills the coatings do add a tremendous amount of wear resistance.Some of them added a "slickness" to the tool that made them much less apt to gall when under extreme cutting prssures.

I have seen the drills bend under certain shop conditions and they would bend as easily as the uncoated ones.
I do think that many of the coatings like the one Buck uses (TiN?) go a long ways in stopping corrosion and rust as well as helping to hold an edge longer.I have wondered if they might be prone to very small chipping
due to thier hardness and no support
at the edge.

We started using the coated tooling for several applications where it was hard to get at to change.The added endurance of the cutting edge helped to prolong the tool life and up the productivity.
Some coatings were definitely better for some applications than others.
Bear in mind that have been out of the shop for almost 5 years now and many of the coatings are new and improved.
I know there were a couple of new ones just starting to be offered when I got out of the business.


The civilized man sleeps behind locked doors in the city while the naked savage sleeps (with a knife) in a open hut in the jungle.
In my experience coatings are much more valuable for corosion and wear resistence than toughness.

You're talking about a pretty substantial coating to have any effect on toughness. I think what Ysva saw was a result of the coated drillbit being made of higher quality materials or something. Also, there's coating, and then there's plating. Plating might have an effect.
Snick the drills were the same brand.
They were a super quality Gurhing made product and some were coated and somewere not.
The coated ones out performed the uncoated ones as much as 7 times.

You're right about the wear and corrosion versus toughness though.

Years ago we used a hard flash chromed tap for tapping aluminium.
Aluminium expands o.0008" for... Well I forgot and all my books are still in my toolbox.Anyway it expands a lot for every small degree of increase in temperature.

The parts were so thin that they expanded enough while they were being tapped as well as the other machineing going on that when they cooled off they were undersise.The part was the pretty nut that holds a famous fishing pole in the handle.
Each one was made in a little less than 6 seconds.on a Warner Swazey automatic screw machine with 6 spindles.
The coated tap helped to keep the parts on size.


The civilized man sleeps behind locked doors in the city while the naked savage sleeps (with a knife) in a open hut in the jungle.
How did the coating help, by reducing friction or conductivity?

I personaly hate aluminum, I don't even consider it a metal, but just a substitute for plastic or sometimes wood. Hot shortness can be a real pain whilst working it, and it's pretty soft too.

Titanium, though slightly heavier as I recall, is ten times the metal aluminum will ever be. If they could only bring the cost down... Not that titanium isn't a pain to work with too, but at least you get something worthwhile for your efforts.
Titanium question - In my local hardware store they claim to stock titanium coated tools to prolongue the tool's life. But when I got a Titanium Tiger from Newt L. it seemed like a soft metal.

What gives?
The titanium used for coatings is a nitride or oxide, not the "pure"(or alloy) metal that is used for structural applications.