A question on historical sharpening.

[Robson Valley]

Hey man! That's not fair!
You're supposed to be rubbing one rock against another and making grunting noises in front of an open fire.
But thanks for all the pictures, anyway.
The round white "crumpet-stone" is the one I want. Really fine grained. That one is the keeper.

Water slurry. No. Don't. The slurry is a slop of smashed abrasive particles which plugs up the cutting stone's surface.
Like oil, the water is no more than the vehicle to flush the swarf off the stone face to keep it cutting cleanly and not plugging up.

On a water stone, after a grind, you can fake a finer grit by letting the swarf build up. I never do.
I want to know that my 1500 grit stone is cutting cleanly at 3 microns average particle size.

Now to action = which way will you go?
Move the stone over the knife edge OR, move the knife edge over the stone?
Which will give you a more consistent bevel angle, stroke after stroke?
What did Mungo Martin do? Hint: One way works far better than the other.

 

[Janne]

excellent experiment.

Next one should be the old bushcraft way. Do NOT flatten the surfaces, use the stones as you found them.
It works.
Do not cut yourself! Slow is pro' !

By keeping the metal/stone slurry, you will increase the cutting abilities.
Do you have a Granite ( natural stone) or Gneiss work top in the kitchen?

The slabs are usually cut with a wire or flat steel band, rotating loop, and the cutting is done by the slurry that forms.

First picture, the top right stone: Granite or Gneiss? One of them I think.

 

[Hammock Hamster]

excellent experiment.

Next one should be the old bushcraft way. Do NOT flatten the surfaces, use the stones as you found them.
It works.
Do not cut yourself!

I tried the stones au naturale on an old beater blade before starting the lapping and they did indeed work, the lapping was really just to see if it was doable and I think I also have that unreasonable modern mindset that sharpening stones should be flat.



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[Hammock Hamster]

Hey man! That's not fair!
You're supposed to be rubbing one rock against another and making grunting noises in front of an open fire.
But thanks for all the pictures, anyway.
The round white "crumpet-stone" is the one I want. Really fine grained. That one is the keeper.

Water slurry. No. Don't. The slurry is a slop of smashed abrasive particles which plugs up the cutting stone's surface.
Like oil, the water is no more than the vehicle to flush the swarf off the stone face to keep it cutting cleanly and not plugging up.

On a water stone, after a grind, you can fake a finer grit by letting the swarf build up. I never do.
I want to know that my 1500 grit stone is cutting cleanly at 3 microns average particle size.

Now to action = which way will you go?
Move the stone over the knife edge OR, move the knife edge over the stone?
Which will give you a more consistent bevel angle, stroke after stroke?
What did Mungo Martin do? Hint: One way works far better than the other.

The “crumpet” was the smoothest of the lot by far and ground to a really smooth flat edge.

I have been pondering the best way to utilise them and normally I would move the knife over the stone as that is how I use most of my current stones, that said they are mostly for scandi grind carving tools where that makes a lot of sense.

Given that they are quite small I could easily move a pocket knife over the flattened area but for larger knives and axes I think I will be moving the stone over the knife which always conjures images in my mind of a farmer sharpening a scythe or perhaps a ancient soldier methodically sharpening his sword before battle.


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[Janne]

I personally also move knife over stone. Less risk of bloodletting.

I have one of those beautiful, expensive sharpening sculptures. The knife is fixed and the stone is moved at a predetermines, adjustable, angle.
Great for the anal-ish sharpening of my Japanese kitchen blades!

 

[Robson Valley]

Ah. So much to learn. As a general class of working tool, early metal edges must have been expensive, hard to make and therefore small.
Won't take much of a stone for upkeep. I think that as you hinted, you are going to come around to long oval shapes as the stones of practicality.
And for heaven's sake, don't get cut. These stones will make a grand, steak-knife "toothy" edge.

I have been cutting up raw bison meat roasts in my kitchen with flint. Those edges are not as long as my little finger.
You would never know that from the speed and ease of preparation, but hopeless for veggies!.
Can't see how a steel edge needs to be any bigger.

Watch Mongo sharpen his knives. He's moving the stone over the stationary knife. I hold my knives to the top of my knee (sitting) and sweep the stone (sandpaper rods) over the bevels.

 

[EdS]

Moulton Whetstone is what you want

 

[Robson Valley]

EdS: does that Moulton Whetstone come from a quarry with a Paleo history?

 

[EdS]

Joys of auto spelling......

Moughton Waterstones. A banded mudstone from the Yorkshire Sales. Traditionally used to hone Sheffield razors.

https://www.google.co.uk/search?saf...1.........0i13j0i13i30j0i8i13i30.zSlrCByHKW8=

 

[EdS]

I've some smalush bits kicking around the garden if you'd like a bit to look at / make a pendant whetstone

 

[Robson Valley]

EdS: thank you and how very interesting.
Would you care to make a subjective guess to compare the grit of the stone to any sandpapers?

I have family in NYorks, just in from Whitby.
Might be a case for a combo birthday/Christmas prezzie.
I can bank roll my curiosity for a piece perhaps a big as my hand.

I suppose that the day came quickly when Paleo people tired of foraging for stone
and discovered quarry deposits that also meant trade opportunity.

It certainly did happen in eastern North America with the Washita and Arkansas stones.
Stone is never an issue in the Rocky Mountains where I live.

 

[santaman2000]

.....I've a book on natural stone hones somewhere. I don't recall which types of rock or where the quarries are for uk based stones. The most well known in modern times would be the american washita and arkansaw(sp?) Stones and the belgium coticule; all are still available from good tool shops like dictum and workshop heaven.....

Be advised you'll probably pay premium prices for genuine quashita (washita) stones though. Those quarries played out decades ago.

 

[santaman2000]

Granite and other stone doorsteps all had odd-shaped wear along them when I was a boy from where folk just went outside and used them to sharpen tools, kitchen knives, scissors etc.

The alternative was to pay a tanner to the travelling men to sharpen it all, but four or five rounds of that would take all the steel and then they'd offer to sell you replacements

This brings back memories of watching my grandmother sharpen the kitchen knives on the back steps.

 

[Billy-o]

I found it! At about 4:30, you see Mungo Martin sharpen his carving tools with rocks.
He carves a watertight, kerf-bent box from western red cedar.

Martin gets a chance to look accomplished here. Better than the poor shot that Pinnock Smith got working with Ray Mears .... bit of an embarassment that program was. I still think it shouldn't have been broadcast, though I expect it all worked out for everybody in the end

 

[MartiniDave]

I grew up in a smallish village in the Cambridgeshire fens. There were one or two houses that hand window sills that had been worn dished over the years by land workers using them to sharpen their "shut-knives" on them. There were also some large paving stones worn dished where the road-men had used them to sharpen their shovels.
I must go back and see if they are still there.

Dave

 

[EdS]

It is sub 5 microns so 4000 to 6000 grit

 

[Robson Valley]

Thanks again, EdS. I think that I can imagine how the stone surface feels.
I use 3M brand fine finishing W&D sandpapers for sharpening wood carving gouges.
They say that 1,500 grit = 3 micron, nominal particle size. They call a 1 micron paper 2,000 grit.
At least they have the common sense to describe real particle sizes.

Stone isn't a building material of interest in my district. Despite having mountains of it, it's all very hard or badly fractured.
It's deep and cheap forest from one tree-line to the next so everything here is wood. See the log pieces in my avatar?
Maybe a little brick (chimneys) and more recently concrete foundations but none of our constructions
are more than 100 years in age. Just plain Paleo, before that!

 

[Hammock Hamster]

Well bit of an update.
For those of you following my other thread this beast of a Bowie arrived today which is intended to be part of my experimental historical/frontiersman kit.

Yes I know it’s hardly the most practical thing for bushcraft but it’s something I have had in the back of my mind for a long time and has now become something of a personal goal to see just how it fares.

Anyway the blade came dull with a oily/waxy coating and once removed showed what look like grinding marks on the blade bevel (happy to be corrected here)

As per my OP I duly brought out my found stones and set to working the edge in the manner of a farmer sharpening his scythe.
The results were interesting as the dull blade now cuts paper with ease and bifurcated a thick cardboard box with no resistance but if anything the blade looks worse in the photos.

The saw tooth appearance doesn’t really show up with the naked eye so either my camera is better than I give it credit for or there is a trick of the light going on here.
Either way the blade both feels a lot sharper and is cutting 100% better than it did out of the box.

I also shot a short video of the sharpening which was even more enlightening.
You will have to excuse the poor camera work (I was trying to reach over a hastily balanced phone and ended up looking a bit jerky) but it did show my hand rotating towards the end of the sweep which in real life felt like it was a perfectly straight and flat trajectory.

If I can’t/don’t correct it I wonder whether there will be a visible change in the blade tip over time?

Anyway I hope this was of some interest and I will let you know how things go over time with this knife being sharpened only with found stones and if I discover any that are particularly good.

Cheers, Hamster


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[Robson Valley]

Fix the blade or fix the stones. Both are wiggling. Impossible to be consistent and repetitive.

 

[Robson Valley]

Another early fault of my sharpening technique:
I was running the stones along the edges. Parallel to the edge. Don't do that.
I learned that the scratches from the abrasive allowed the edge to fold up like the flap on a postal envelope.

Holding the needed bevel angle, the abrasives have to run out at right angles across the edge.
Means a lot of short strokes with a small stone and a bigger risk of getting cut. Gloves?