Hardened or Coated-Steel Knife Material

Use and value considerations of plasma-coated or hardened cutters. August 30, 2007

Is anyone using Titan Knife brand M2 moulder knife stock? I have no clue if they are any good. They say they have a V3 grade steel with diamond vapour deposited films for added tool life, but I am not fond of Chinese made tools (you get what you pay for!). I'm curious to know if anyone has success with these.

Forum Responses
(Solid Wood Machining Forum)
From contributor R:
Yes, we use quite a few Titan products as well as Leitz and WKW. I thought the same as you did about the Asian products, but after much testing, our customers are very pleased with the results. I use a great deal more of their M-2 black nitride. The V3N is very hard, and a bit tough to grind, but will last a long time. The black nitride will also last a long time but is a bit easier to grind. Their standard M-2 will stand up to most standard M-2 steel. We use American steel, German steel, and Asian steel, and you can rest assured they all are good quality products. Check out Global Tooling in Oregon - they are the importer of Titan steel and are just great people to work with.

From the original questioner:
Thanks for the assurance. Do you know if the V3 is troublesome to grind?

From contributor R:
I wouldn't say troublesome, but you will notice it is harder to grind and it will burn easier. Lots of coolant from the bottom of the knife and sides, and keep your grinding wheel dressed - it will load up more often. In short, grindermen hate it, and moulder operators love it. Try a bar of the black nitride as well as the V3n - I think you will like both of them but the black nitride will be easier to grind.

From contributor J:
We use M3+ with good results in the grinding room and on the moulder. Would V3N or the black nitride last longer in between sharpenings than M3+ milling hard maple? Something I might want to try?

From contributor M:
I personally stay away from too brittle a tool steel... Had a Weinig m3+ knife shatter on me. I'm lucky I didn't wear it. Thing is, too, you don't know what the exact country of origin these are manufactured in is these days. In all, M2 at 62 Rockwell hardness is easier to maintain.

On an additional note... I was talking to one guy who plasma sprays carbide, chrome and ceramic onto moulder bed plates to refurbish them. He tells me he has seen plasma/thermal spray knife stock with Carbide/ceramic. He says it's very prized by his customers. I have yet to try this out.

From contributor R:
Yes, you would notice longer run times with either of them, but keep in mind, the harder and higher you go up the Rockwell scale, the more prone to chipping, as mentioned. Also, a borazon wheel for the harder steels is recommended. Try it, I am sure you will see a difference.

From Dave Rankin, forum technical advisor:
There are some concerns about knife steel and some of these have been presented already.

The heat treating process of the tool steel is very important. The metal makeup is also important. I have tested and had the metal makeup checked on many tool steels. I agree with some of the posts, the name M2 normally indicates a certain makeup of steel. However, I have discovered at least three steels that are listed as M2, but test out as something different. Caution should be given to buying tool steel by grade only. Knowing and trusting your supplier is very important.

The heat treating process can cause the steel to be brittle. This is uncommon. The things I look at in a tool steel include:
1. Surface ground versus radial ground on the face.
2. Flatness of the steel; this indicates much about the heat treat process.
3. Depth of corrugation.
4. Alignment of corrugation.
5. Method of heat treating.
6. Metal makeup.

As for the coated steel, there are many available. Many of them work very well. Others do not. Potential problems with coated steel include:
1. Too thick of coating resulting in flaking of the coating.
2. Improper or inadequate coating.
3. Variation in the coating thickness.
4. Damage caused while grinding from the grinder's tool rest.
5. Damage by the operator.

Coated steels should not be honed on the face, as this can result in damage to the coating. Many of your vacuumazation processes provide a consistent layer and improved life of the tool. The DGK-ACT coating that we have used for 7 years does this. Heat reflection of over 2200 degree F, hardness exceeding carbide, ground with standard abrasives, increased lubricity of the tool face and long tool life.

Look at your production run requirement, cost of the tool steel, grind time and overall real cost to determine which tool steel to use.

I have used laminated steel, sold by many different companies over the years, and most of the time it runs well. I have, however, experienced several times where the backing was not strong enough to handle the rotational load, resulting in a tool breaking or the backer rolling back against the head body. Once again, buy from a company that you trust. There are many of these throughout the world.