Thread: Cheap water stone is that false advertising

Originally Posted by cotedupy1

That's very interesting about Wheal/Mt Osmond mine! I spent a little while recently trying to research about that kind of thing, and it's remarkable how little information or history I could find about (European) Australians' use of natural Australian whetstones. There was the quarry at Mudgee, but that seemed to be about it. Also interesting because I live about tens mins away from there, in Aldgate.

So I'm off now to spend an hour or two trawling through the internet to see if I can find out more...

That slate sure is pretty, if nothing else.

Here is a map of the old mines at/near Mt Osmond. But, I'm not sure which one of those was referred to as the source or for that matter the quality of the stone on offer.

https://www.weekendnotes.com/im/006/...kins-sil81.jpg

Very interesting discussion!

After maintenance sharpening my kitchen knives on 2 waterstones - 2000 then 5000G - I strop them on leather coated with green compound.

I then "revive" their edge after some use with a steel. In the process, I have noticed that the nice shiny edge left by stropping becomes quite scratched by the use of the steel. I would have thought that such scratches are the result of the abrasive action of the steel.

I would have also thought that achieving a keen edge by any sort of friction, including "honing" would be - by definition -the result of abrasion.

I have to confess that I do not appreciate the finer distinction and ultimate effect between honing as an abrasive action as opposed to honing as a "re-arrangement"?

Cheers,
Yvan

Originally Posted by yvan

I have to confess that I do not appreciate the finer distinction and ultimate effect between honing as an abrasive action as opposed to honing as a "re-arrangement"?

I expect few of us do, Yvan.

If my experience with burrs on scrapers is anything to go by (it may not be) a rearranged edge is going to be far less durable than a freshly exposed edge of base blade material created through abrasion.

Re-arranging the metal to reform a micro-edge may be quicker to achieve and effective for awhile, but not last as long as a freshly re-ground micro-edge that usually takes longer to achieve. Deciding where to put your effort then becomes an individual choice.

The "honing compound" that I use is clearly an abrasive. The black streaks of steel residue on the strop show that.
Of course, the surface appears polished. This is so finely scratched that the unaided human eye does not have the resolution to see it.
All the same, it seems to be an essential final step for the edges of wood carving tools to be used in very soft woods.

Originally Posted by Robson Valley

The "honing compound" that I use is clearly an abrasive. The black streaks of steel residue on the strop show that.
Of course, the surface appears polished. This is so finely scratched that the unaided human eye does not have the resolution to see it.
All the same, it seems to be an essential final step for the edges of wood carving tools to be used in very soft woods.

RV, I'm neither a shaver nor a carver of soft woods, so have no doubt that you have found the right solution for your particular needs.

Perhaps the following two blog articles that go into stropping, with some SEM images to illustrate what is happening at the micro level, may be of interest to you. My interest was/is in understanding how burrs form during the sharpening process. Your focus (no pun intended) may be quite different.


What is a burr? – part 2 – scienceofsharp

The Pasted Strop – part 3 – scienceofsharp

I agree. There might be something odd about my process.
However, it does an excellent job on blades from spoke shaves and Stanley planes.
I use a lot of black felt marker even now to follow the steps in the process.
I sharpen from my knees, never from my elbows. That seems to sustain the geometry of the bevel.
The burr shows that you have run the sharpening out over the edge so that step is complete.

I stop with 1,500 grit (3 micron) and do a final honing on a hard strop with CrOx/AlOx.
There are two pages of SEM photographs in Leonard Lee's book: The Complete Guide To Sharpening.
The photographic evidence showed me that there was really little need to go beyond 1,500 (3 micron)
as thin steels are soft and plastic.

Originally Posted by Robson Valley

There might be something odd about my process.

Nothing odd about it as far as I can understand. The old boot maker that I used to watch in his workshop back in the 1950s used almost the same process.

If it works for you, it works!

Sharpening from the knees up sounds a bit like what I tell anyone I am teaching to woodturn; turn from the hips, not the elbows; I abbreviate that to start the cut with the "lathe tango".

Originally Posted by Robson Valley

There are two pages of SEM photographs in Leonard Lee's book: The Complete Guide To Sharpening. The photographic evidence showed me that there was really little need to go beyond 1,500 (3 micron) as thin steels are soft and plastic.

Does Lee say what steel those SEM images are of?

As we know, modern blade steels vary in their alloy composition and that changes their plasticity/elasticity (ductility <---> brittleness).

Elasticity of steel alloys.jpg

The steel and blade making process also determines the carbide composition (austenite and martensite) and their distribution, which also changes its ductility, hardness, brittleness and toughness.

I find that some steels, for some uses, benefit from sharpening down to about 1 micron, while for others there isn't a return on the time and effort required to do that.

I've been experimenting with power stropping some of my turning tools with the DW's unicorn method, but I'm not convinced as yet that I'm getting an overall benefit from doing that. However, I can see the the benefits of getting a high 'polish' on gouge flutes and the upper bevel of scrapers using that method, if for no other reason that it is quicker.

Time to go and chop some wood. I find the edge at about #1,000 is sufficient there.

No Neil, Leonard Lee does not specify the steel except for a couple of sorry SEM of a Wilkinson Sword razor blade.
He just says it's a chisel. The geometry of the big SEM machines is such that you can't stuff the entire specimen into the chamber (chisel tip.)
No notes on bevel angles and certainly no evidence of service.
Get the book on some sort of an Interlibrary Loan and have a read. LL has tried to be all things to all people about sharpening.
I was disappointed just a little so I expect there is stuff missing in other chapters as well.

As I expected, all steels look the same. They feather out, thrashed with abrasive scratches.
Big or little, they all look the same because steel is steel. Not broken along a line of molecules as is knapped flint.
As thin as bevelled edges, the metal looks really soft and plastic.

Prices? I pay $40- $60 each for Pfeil gouges from open stock. Pacific Northwest crooked knife blades are about the same
but the adze blades run $100 or more USD. I figured out how to use junk hoof knife blades for $5 each.

OK. I carve soft western red cedar and some yellow cedar. I like to carve (Betula papyrifera) Birch as a featureless hardwood.
They are the traditional and local carving woods in my part of the world.

What can I do for a freehand sharpening process which is entirely adequate for a 940g lead-core mallet strike?
1. Look at the edge in LED light to see damage.
2. Bad? start with 600, good? start with 800.
3. Then 1000 then 1200, then 1500 (I use 3M wet&dry papers, the particle sizes are specified. No grit BS numbers.)
4. Honing on a hard flat strop with CrOx/AlOx is important as a final step. I can tell just by the "push" effort
to cut the wood when the sharpening process is finished and good for 30-60 minutes of steady work.
To this end, I have a dedicated "try" stick for testing edges.

I've not stropped previously*.

When buying a strop (RV above: hard flat strop) where/what does one buy this?

Is there a product I can buy that is GOOD... can anyone make a solid recommendation?


Should I even bother with a strop and simply just jump to the unicorn method? (I did read the long post/thread about it and I'm convinced of its application).


* a slight lie. I did do so with the inside-side of cereal box cardboard and a green bar of Veritas stick. But I'd regard it more an experiment than a process

Honing can be carried out using an abrasive compound/item. We hone engine cylinders, after re ringing or after reboring using aluminium oxide stones.

Wood Central has a lot of info on the Unicorn method and I think Derek Cohen has become a bit of a convert as well and may have some information on his website. As for honing, I have always done it on a piece of MDF, cheap, disposable and it works for me. There are so many paths to sharp but the Unicorn method seems the most economical especially as cheaper blades respond so well and then perform as well as blades that cost a lot more which was its intended use in the first place. DW has put up some YT video worth watching, I think the speed is what appeals to a lot of people.

Originally Posted by woodPixel

I've not stropped previously*.

When buying a strop (RV above: hard flat strop) where/what does one buy this?

Is there a product I can buy that is GOOD... can anyone make a solid recommendation?


Should I even bother with a strop and simply just jump to the unicorn method? (I did read the long post/thread about it and I'm convinced of its application).


* a slight lie. I did do so with the inside-side of cereal box cardboard and a green bar of Veritas stick. But I'd regard it more an experiment than a process

With the caveat that my experience is mostly of sharpening Japanese kitchen knives, not razors or tools... the inside of a cereal box is an *excellent* thing to strop on. Most of the best knife sharpeners I know use unloaded cardboard or paper.

Hard, flat strops. Anything flat that I can scribble with a bar of CrOx/AlOx Strips of cereal box cardboard, any hard flat packaging.
Glueing it down is a myth. Gravity is your friend. Dabs of masking tape at each end are perfect.

Because I carve so much with the crooked knives and adzes of the Pacific Northwest First Nations, I need mandrels.
Pieces of pipe, lawn chair legs, dowels, even a tennis ball. A big Stubai carving adze is a 7/75, perfect fit for a tennis ball.

On the cylindrical forms, I like 4" x 6" office filing cards.
Stuck at each end with a dab of electrician's tape or whatever else I can find at that moment.
Then scribble green. No sweat if it doesn't turn out too even, you knife will never notice.