Tool Steel Wear

[Todd Bin]

Hello all,

I was recently looking at some turning tools and noticed the various steels available. Some claim 3X the wear some even more. In searching the edge of the internet today I found this data. It is interesting and the study appears to be quite scientific. I have posted a graph of the data in case someone doesn't like the link to the article. It says that compared to M2 steel, ASP60 has the best performance at 2.5X the wear time.

http://www.theokspindoctor.com/ -- see the last article

Enjoy.

Todd

[Nathan Hawkes]

Todd, the link doesn't work. It takes you to the "spin doctor" website, but says "oh no, we couldn't find anything". I am somewhat skeptical of the analysis graph, only in what specific wear analysis they perform. I find my 10V tools to outlast my 2030 and pro-PM tool steel turning tools. This seems like a very subjective analysis, in terms of "predicted
relative wear" rather than, for example showing a microscopic analysis of a tool edge before and after a certain amount of cutting, with the same amount of time turning a given piece of wood.

Many "tool steel" comparisons that I've seen are geared towards machining metal, and not cutting wood on a lathe. I'd love to read the article, but could not find it on that website.

[Todd Bin]

That is frustrating. I am looking for the article again. If you pm me your e-mail I could send you the article once I find it. I am not sure how to attach it here.

The study was done on wood with a constant feed rate. SEM images were taken from the edge of each type of tool. Additionally the monitored the current necessary to maintain a constant feed rate. The current increase is how they knew the tool was getting dull. It appears to be very well done. Lots of graphs, explanations and data.

I will post once I can find it again

~Todd

[Jake Helmboldt]

Here is a link to the study. I haven't read it, but the table is the same so this should be where it originated. It was conducted at NC State, so it wasn't just some hobbyist's perceptive review of wear resistance. But that is also no guarantee of anything. Also, while the various tool steels have different wear resistance, there comes a point where they may not dull further very uickly, but may be too dull to be truly useful. In other words, it is the keenest edge that cuts well and quickly degrades, regardless of the material. The longevity of an edge if determined by which can hold that reasonable degree of sharpness at say (arbitrarily) 80% of "max sharpness vs. another that may continue to degrade beyond the "kind of sharp" stage.

http://www.morewoodturning.net/reviews/Tool%20Wear%20Testing%20by%20Jim%20Staley.pdf

[Todd Bin]

Yep, this is it. THanks for posting a link that works.

~Todd

[Dale Miner]

In reading the data and looking at the charts, I'm not sure that I understand the conclusions. With M2, at about 4 cubic inches of wood, the milliamps were over 220. With the 15V it took about 22 cubic inches of wood to make the required amperage reach the same mark that M2 did with 4 cubic inches and it appeared that the amperage was pretty much leveling off at the 220 mA mark with the 15V, while the amperage was rapidly climbing with the M2 at 7.5 cubic inches, and reportedly was burning the wood on the final cuts. It would have been interesting to see charts of the increase in power needed to spin the disc during the cuts.

Also, the tests were done using tooling in a neutral rake scraping mode. I wonder how the different tools would do in an actual high positive rake peeling cut mode.

I actually bought my tools for the flute shape anyway.

Later,
Dale M

[Bill Blasic]

I agree Dale and I know from actual use of A11 that it lasts way longer than M2. Of course I'm using a lathe and not a Ring Master.
Bill

[David Gilbert]

This article is the same one that Ernie Conover referenced in his "The Frugal Woodturner" book. He uses the data to estimate the relative cost of tools with the different steels. If an ASP60 tool costs less than 2.4 times the cost of an M2 tool than it is a better bargain. If it cost more than 2.4x than it isn't. Note that his book focuses on being frugal. Ernie also notes that tool steel wear on wood isn't the same as wear on metal cutting. Another good point that Ernie makes is that if you are just learning to sharpen your tools, it is better to learn on the cheaper HSS tools rather than the expensive powdered metal ones.

Cheers,
David

[David E Keller]

This article is the same one that Ernie Conover referenced in his "The Frugal Woodturner" book. He uses the data to estimate the relative cost of tools with the different steels. If an ASP60 tool costs less than 2.4 times the cost of an M2 tool than it is a better bargain. If it cost more than 2.4x than it isn't. Note that his book focuses on being frugal. Ernie also notes that tool steel wear on wood isn't the same as wear on metal cutting. Another good point that Ernie makes is that if you are just learning to sharpen your tools, it is better to learn on the cheaper HSS tools rather than the expensive powdered metal ones.

Cheers,
David

Not to hijack the thread, but how is that book? I've thought about buying it, but I haven't pulled the trigger yet.

[David Gilbert]

Not to hijack the thread, but how is that book? I've thought about buying it, but I haven't pulled the trigger yet. David,

I borrowed the The Frugal Woodturner book by Ernie Conover from my the Rochester Woodworkers Society library so I haven't had to buy it. I like the book and it has some very interesting sections and suggestions about getting good value for your money. There are a number of very useful suggestions about tools and jigs that you can make or buy. I think that the book is targeted more at the beginner/intermediate turner. This isn't a lot about technique or methods of turning but there is a nice section on sharpening. I was planning on buying it but our library got it first so I'll probably get another book.

Cheers,
David