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A layman's musing about HSS, ASP, M and Rockwell C

I once posted for fellow dummies, my way of thinking about phase of electric power. Some of you pretended to like it, so I'm brave (dumb) enough to post my way of considering the steel in our turning tools. It may help somebody to understand catalog descriptions and manufacturer's specs. Engineers, chemists, metallurgists and machinists can leave now or stick around to correct my errors, cares and woes.

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Five properties of steel that concern us and can be made to vary independently are:

  1. resistance to bending or deforming as in bent spindles or mushroomed knockout bars (hardness)

  1. resistance to chipping or fracture or breaking at notches as in broken files and tangs. (toughness)

  2. resistance to abrasion or eroding as in quickly dulling a gouge edge (wearability) note that this need not be related to hardness

  1. Resistance to softening with heat as in bluing carbon gouges (annealing)

  2. Resistance to spending money as in staying within budget (price)

I think of steel as a soft iron matrix with hard and tough particles of a carbide (a compound composed of a metal and carbon) suspended in it. Sort of like the silicon or aluminum grits suspended in a grinding wheel's matrix. The metals and the size and distribution of these carbide particles determine the above five properties for our steel turning tools. There are three basic types: high carbon, high speed and powdered. Solid carbide isn't considered. It's hard but not tough.

  1. High Carbon Steel tools in which carbon is mixed with iron to make hard iron-carbide particles. The more carbon the more particles and the more the better up to the point where excess carbides join together to become large irregular and poorly distributed particles in the iron matrix. Just adding more carbon doesn't help, so the performance of high carbon steel tools has a limit.

  1. High Speed Steel tools made of metals that produce carbides with higher qualities than iron-carbides. Usually these metals are chromium, molybdenum, tungsten and vanadium in ascending order of their superiority ....and cost.

  2. Powdered metal tools in which superior carbide particles of small (powder) size are distributed uniformly in an iron-cobalt matrix. This powder is compressed into steel bars of higher qualities....and price.

This is just a way of thinking. I hope it isn't too inaccurate or even more confusing than texts or authoritative discourses. Anyway, I've gone too far to erase it now, so smile, forgive and add a grain of salt to the steel. :)

Turn to Safety, Arch Fortiter

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Arch
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Arch:

I've been reading the current Craft Supplies USA catalog. Let me quote some of it...

"Testing: Hamlet ASP2030 and ASP2060 vs Standard M2 High Speed Steel"

...

"ASP2030- The ASP2030 gouge cut fast and clean, removing more than 2,083 cubic inches of material, nearly 300% more than the M2 gouge."

"ASP2060- The ASP 2060 gouge performed similar to the 2030 tool regarding cutting ease and fast removal. However, this gouge removed more than 3,160 cubic inches of ash, the cutting edge lasted 4 1/2 times that of M2, and exceeded the edge life of the ASP2030 gouge by nearly 50%."

Now let's go to the description of the Mike Mahoney Signature Tools...

Mike's tools consist of three different gouges. The roughing out gouge is made from 2060 and the finishing gouge is made from 2030. Now, the description of the Mahoney interior bowl gouge...

"...The M2 tool steel is softer than the ASP2060, but can be ground to a sharper edge, therefore producing a cleaner cut on the wood...."

Most of us have bought into the theory that carbide is great for router bits but lousy for turning tools -- it just can't be made sharp enough. So how is the case with powdered metals any different?

Also, it seems to me that if Most of my bowl gouges are M4 (Oneway), the other store-bought tools are M2 and the home-made ones are, variously, of M2, O-1 and sometimes I don't even bother to harden specialty tools. I just don't believe that powdered tools will make me a better turner, nor a faster one.

Bill

Arch wrote:

Reply to
Bill Rubenstein

Arch, These issues arise for bench chisel and hand plane users as well as wood turners. There are some objective findings in that arena that are most informative for woodturners. Steven Elliot has been engaging on some of the best objective comparisons of blades of various alloys and has some most interesting findings, primarily that all steels can achieve a sharp edge if you use the right abrasives (a finding I will immodestly say I have long held). And, of course, the edges considered important for hand plane use far exceed the edges customarily put on turning tools, even skews. Indeed, for those of the 80 grit is good enough belief, the carbide inclusions are miniscule compared to the abrasive grooves.

Steve's site is here:

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the some of the most pertinent information available at the Summary of Results link.

Lyn

Arch wrote:

Reply to
Lyn J. Mangiameli

Thanks Bill & Lyn for your usual good responses. I hope my thread prys up more like them. I was mostly musing about the components of our steels and why all high carbon or high speed steels are not created equal, rather than about using them. Actually, all my tools are M2 or 'Sheffield carbon'. I suppose that it's not only the sharpness of the edge to be considered, but also that solid carbide tips fracture much easier than powdered steels.

Turn to Safety, Arch Fortiter

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Arch

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