Steel question - sharpness vs hardness

[Thom Sturgill]

I just took a weekend course with Alan LeLand. He re-grinds his spindle gouges between 35 degree for normal work and 25 degree for finish cuts. Naturally he goes through gouges rather quickly. I know from my neander leaning period that there is a curve - Hardness on one scale, sharpness on the other and you need to find the sweet spot - soft enough to take a sharp edge and hard enough to keep it long enough to be usable. Neanders want good carbon steel. We (normally) want cyrogenically treated HSS.

We DO NOT sharpen our gouges as sharp as a neander does his plane, but we keep a usable edge much longer in terms of cutting inches. Carbide is currently the leader in hardess, but does not get as sharp an edge (newer micro-carbides are much better than say router bits) but are more expensive and need special sharpening tools so they are typically limited to screw on tips and don't have the finesse of a well ground tool.

Here's the point of this ramble - if I intend to dedicate a spindle gouge to the 25 degree grind and use it only for finish cuts, I would probably *hone* at each use. Carbon steel would probably work, but no one (that I know of) is currently manufacturing carbon steel turning tools. Now, I love my Thompson's (I have six), but I wonder if I would not be better off with some other steel (M2?) for a dedicated finish-cut gouge. And which steel / brand would I want?

What's the collective experience say? Is there some particular gouge (spindle or bowl) that you turn to for those finish cuts because it takes a sharper edge? If so what is it?

[Clint Baxter]

If I remember correctly, you can get a sharper edge off a harder edge, (remember glass here), but the problem ends up with that edge being too brittle. You're more likely to chip that super sharp edge because the steel doesn't have enough ductility. The other problem is finding something that will sharpen that hard steel, if you want to get it super sharp as well. The best knives I have are the hardest as well, (and the hardest to sharpen). But when I get a keen edge on them, they hold it for a much longer time as well. If you sharpen your Thompson up to a razor edge, (I do for my skews), it should hold that edge much longer than an old high carbon turning tool.

I use my Tormek for those tools that I'm going to hone after grinding, and polish the edge using the leather wheel.

Even if you back off to a HSS tool, the same applies, it just won't hold it's edge as long as the PM tools will.

[Gary Conklin]

I love my Crown gouges for a nice sharp edge, use them for my finish cuts.

[Thom Sturgill]

Here (http://www.britishblades.com/forums/showthread.php?105462-what-steel-takes-the-sharpest-edge/page4) is a discussion of hardness vs sharpness. Another (http://bladetest.infillplane.com/html/steel_and_sharpness.html)site talks about sharpness and edge retention in plane blades. Reading these I don't think the type of steel is as important as the treatment, so the question stands. What gouge gives you the *sharpest* edge? I'm not as interested in your sharpening technique (that's a separate subject) as I am the steel. My primary workhorse gouge will remain the Thompson.

[Joshua Dinerstein]

There is a cheap set of tools from Harbor Freight. I started with them years ago. Where you got 8 tools for $9. I was told when I upgraded to the HF HSS set that they were high carbon steel. I don't know that they really are or that you would be interested in such tools but I thought I would mention them to you.

In fact come to think of it, I have still have a new and almost entirely unused spindle gouge from that set. It is yours for the cost of shipping if you want it. :)

Joshua

[Thom Sturgill]

Joshua, I have the same tools. The spindle gouge fried when Alan tried to sharpen it with a thin edge (35degree fingernail grind), so they will not work for what I want.

[Gary Conklin]

My Crown tools are not the PM versions, but the regular M2 HSS.

[Bernie Weishapl]

My Thompson tools (spindle and bowl gouges) stay sharp for at least twice as long as my HSS tools. I sharpen all my gouges on a Tormek and all are honed. This is just my opinion that the tools including HSS I dress and prepare with the tormek including honing stay sharp a lot longer than off the dry grinder. It may be me but those are my observation.

[David Walser]

Thom,

I'm not sure if I followed your question. Rather than regrinding the gouge for rough cuts and again for finish cuts, I think I'd buy two gouges and keep one at my "rough cut" bevel angle and the other at my "finish cut" angle. (Which sounds like your plan.) With either gouge (35 degree or 25 degree), I would hone. I've become a believer in honing the edge of all my turning tools.

Allan Batty has a video out, The Skew Chisel, in which he discusses the proper bevel angle. He says the proper angle depends on several factors. Softer woods need sharper angles to cut cleanly. Such angles, with their thin edges, won't survive long when used on harder woods. The swirling grain of some figured woods will also come into play in determining the "ideal" bevel angle for a clean cut. So, the ideal bevel angle for getting a clean cut may differ from one blank of wood to the next. In addition, the bevel angle also affects what kinds of shapes you can turn. For example, a skew sharpened at a 25 degree angle may have a very long bevel. Such a long bevel may make it difficult to use the skew for turning a small bead (but it might be perfect for a planning cut).

Allan's bottom line: the proper bevel angle is typically a compromise of sharpness, durability, and geometry. He suggests finding one angle that works for you and the woods you typically turn rather than switching from one angle to another. It's easier to master proper technique if the tool geometry is consistent, and proper technique and a light cut is apt to produce better results than a sharper bevel with so-so technique.

Here's a link to his video: http://www.woodturnerscatalog.com/store/Videos___Techniques___The_Skew_Chisel___batty_skew _vid?Args=

[Thom Sturgill]

David that is the point - I have three 5/8 bowl gouges each with a different grind for different aspects of bowl turning. As I return to doing spindle turning, I want to improve the tools at hand and keep several versions of the most used size, each with a different grind.

For that final, clean up pass the critical aspects of the tool are sharpness and the ability to accept the desired grind. Not how long it holds the edge. I also hone all my tools as I find that they both get a sharper edge and hold that edge longer. I often compare a honed tool to a good chef's knife and a ground edge to a serrated kitchen knife.

So again, what STEEL (or Manufacturer?) takes the best edge in your experience?

[Ryan Baker]

For the sharpest edge, I would go with M2 over any powdered metal. I would not drop down to carbon steel -- the benefit over M2, if any, is just not significant.

[Joshua Dinerstein]

Joshua, I have the same tools. The spindle gouge fried when Alan tried to sharpen it with a thin edge (35degree fingernail grind), so they will not work for what I want.

Bummer. Sorry. I had hoped it would help you. Good luck on locating a better one. I would think that your best bet is probably the old craftsman tools that show up on Craigs list and garage sales from time to time. I saw a number of them at a garage sale about a year ago.

Good luck,
Joshua

[Doug Thompson]

My thought on part of your question is...

If you grind steel with a 80 grit wheel you'll have scratches from a 80 grit wheel it doesn't matter what grade steel is ground. If you need a sharper edge use a finer grit... that's why the leather wheel on a Tormek works so well.

[Thom Sturgill]

Personally, I would not consider anything coming off of an 80 grit wheel anywhere near sharp.I forget whether it is 120 grit or 150 grit, followed by compound on an MDF wheel followed by an 'ultra fine' diamond hone with occasional 'touch ups' with the hone.

[Neil Strong]

Found my Ellsworth sig gouge gets the sharpest edge for fine finishing cuts.

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[Thom Sturgill]

Found my Ellsworth sig gouge gets the sharpest edge for fine finishing cuts.

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Which Ellsworth ? - its available both as M2 and PM. (I like mine too, I have the M2 version ) - ahh the signature version is listed as M2 and the PM version does not say 'Signature'.

[Doug Thompson]

Let me clarify my last statement, any piece of steel will be just as sharp as the next when sharpened the same way, one steel won't be sharper. A tool sharpened to 25 degrees will need to be sharpened often no matter what steel is used.

IMO - pick the tool that you have the most control when using and sharpen that to 25 degrees.