Exotic Steels for Scrapers

[chipmunk]

Have others tried using Cobalt HSS tool steels for scrapers?

Hamlet produce turning tools in ASP 2030 and ASP 2060 which contain Cobalt for better wear resistance (M2 has no Cobalt) and I seem to remember a few reviews of these tools as bowl gouges which were positive in the mostpart but almost certainly I reckon because of the cost they don't seem to have caught on.

I like making small boxes and so have made a few of my own scrapers - usually out of metalworking HSS toolbits which are often 5% or 8% Cobalt. Although these are harder to shape and grind than good old M2, they seem noticeably better at holding their edges.

Since I reckon the unsupported cutting in a scrape is harder on tools than supported cutting I think it might be worth trying more exotic steels here. Any thoughts?

Jon

 

[Richard Findley]

Hi Jon

You might find this article of interest: http://www.cindydrozda.blogspot.co.uk/2 ... d.html?m=1

Cheers

Richard

 

[chipmunk]

Hi Richard,
Thanks - yes that's very interesting.

I must admit I haven't tried any scientific or even informal testing - it was just a hunch that the Cobalt based steels were better than M2 at holding an edge while scraping.

The relative merits of M35, M42, ASP20X0, which get their wear resistance from Cobalt, and 10V, 15V, which gets theirs from Vanadium, seems to be a bit of a debatable point, particularly since ASP20X0 and 10V/15V are proprietary steels rather than standardized "recipes", but all do have better resistance than good old M2.

It's reassuring to know that someone else is thinking along the same lines though that scrapers benefit from that wear resistance and Cindy was saying that negative rake scrapers especially benefit. I also agree with her point about the sharpening of these exotic steels - M42, in particular, certainly is tough stuff but can be brought to a good edge with a diamond hone.

The ironic part is that when I checked the Hamlet website looking at the ASP2030 and ASP2060 range, the picture showed big bowl scrapers but the range now only seems to include gouges and parting tools :roll:

Thanks again
Jon

 

[KimG]

Doesn't she say that M42 can be sharpened satisfactorily with standard stones? But it is the 10v carbide types that require a CBN or similar to get an edge due to the brittle nature of the steel and the inadequacy of lesser stone to cut such steel, thus leading to shattered rather than sharpened edges.

I am pretty sure she doesn't say that M42 cannot be sharpened with any type of standard or hard stone. At least that's how I read the piece anyway.

 

[chipmunk]

Hi Kim,
A case of too many M numbers I think :wink:

I don't think Cindy mentions M42, just M2, which is the usual HSS almost all turning tools are made of.

M42 has 8% Cobalt and M35 has 5% Cobalt - these are the exotics that metalworking toolbits are often made of.

HTH
Jon