F&C 226 Demystifying the numbers – choosing a system

[Dovetaildave]

I've just bumped into this article By Brian Green and found it very informative.

Being the owner of various sharpening mediums over 25 Years, I have found I generally go with Diamond plates and polish with either; worn diamond or King waterstone, wet n dry or leather strop and 25 year old autosol from my biking days.
In recent years I have accumulated some different steels including O1, A2, laminated smoothcut, etc
I found it interesting that the writer was confident to suggest a brand/medium to move to if you were using particular brand/medium, and a consideration to the steels being sharpened

I don't know if I'm allowed to cut n paste the entire article here, but I imagine I can include a little snip maybe....

"One micron = one-millionth of a metre. The symbol is ‘μ’. A typical human hair is approximately 40μ.
When converted to microns, it becomes apparent that particle size can vary greatly between brands. Recent testing reveals that not all 1,000 grit stones – or 4000, or 8,000 – are the same."

"As an illustration, a comparison of fine waterstones indicates these anomalies in our previous assumptions:
• Norton 8,000 stone is rated 3μ
• King 8,000 is 2.5μ
• Sigma 10,000 is 1.5μ
• Imanishi 8,000 is 1.2μ"

There's a lots to read and take-in in the two page article, I'm sure I will return to if for reference in the future years.
Thanks for this Brian =D>

 

[Cheshirechappie]

I'm not sure that level of detail matters too much, really. Interesting in passing, but by no means essential. As far as grit sizes go, bigger numbers mean a finer stone, smaller numbers a coarser one - and that's not far off all you really need to know.

Sharpening really boils down to a three-step process; coarse, medium and fine.

The 'coarse' step is used occasionally for the repair of gross damage and the re-establishment of a primary bevel after a lot of honing, and usually takes place on a grindstone; electrically powered, hand-cranked, dry or wet, it doesn't really matter as long as it suits you. Some people do their regrinding by hand on coarse stones or abrasive papers. This works, but it can take a long time.

The 'medium' step is the real workhorse of sharpening, often called honing. Whether you choose a fine India oilstone, a medium diamond stone or waterstone, or a medium grade of 'scary sharp' abrasive paper or film doesn't matter - again, choose one that suits you - it's the step that gives most tools their working edge. Either freehand or with a jig, doesn't matter which - they both work. A whap across a strop after honing helps to remove the last of the wire edge, and refines the edge a bit.

The 'fine' stage is reserved only for when you need a super-sharp edge, perhaps for finish planing or paring end-grain on something that will show on a finished piece. Use a stone with a very smooth feel - something like translucent Arkansas, Welsh slate, a high-number waterstone or diamond stone. Use it with a gentle touch on a freshly-honed edge to refine the finish on the very edge, that's all. Touch up the edge regularly to maintain that degree of sharpness. For the general run of stock preparation planing, chisels for chopping duties, marking knives and the like, this stage isn't needed.

The 'system' thus boils down to a grinder of some sort, a medium-number honing stone, a smooth-feel (biggish number) polishing stone and a bit of hard leather glued to a block of wood for a strop. For tools with straight edges, that's all you need. When you acquire any tools with curved edges, you may have to add a slipstone or two, or shape a few slips of wood and glue suitable grades of abrasive paper to them, even make curved leather strops, but follow the same idea of coarse/medium/fine.

Anything else is just over-complicating it, really.

Edit to add - choice of sharpening medium might be influenced a bit by the types of toolsteel you have.

If any of your tools are of the fancier modern steels such as A2 or D2, maybe veer towards ceramic or diamond hones and polishing stones. (Some people say A2 sharpens on oilstones, some say it doesn't - I don't know who's right!) If you stick with the simpler modern steels or with vintage tools, then diamonds, waterstones, oilstones, ceramic stones and 'scary sharp' abrasive papers and films will all work perfectly adequately - the choice is yours.

 

[Jacob]

.....
Sharpening really boils down to a three-step process; coarse, medium and fine. .......

Anything else is just over-complicating it, really.......

Agree. The numbers are just a confusing distraction!

 

[Corneel]

There's another problem with these micrometers. Different types of sharpening media have different sharpening characteristics. For example, in these tables the oilstones always look like roughing tools, because their grit particles are so large. But the shape of the oilstone particles and their way of grinding the steel is different from how a waterstone or sanding paper works. The latter always present fresh grit, while an oilstone has more rounded particles.

 

[David C]

I don't think there is a problem at all!

Fine waterstones produce better edges than oilstones. They also cut faster.

Stropping becomes unnecessary.

 

[JimB]

As said above, numbers on stones are just a comparative aid like numbers on a saw-set.

 

[Corneel]

I don't think there is a problem at all!

Fine waterstones produce better edges than oilstones. They also cut faster.

Stropping becomes unnecessary.

Well maybe, but waterstones are messy, they dish relatively quicky, they are easilly gouged when sharpening narrow or curved stuff and they are no fun in the cold.

Every sharpening system has its pros and cons. And it's up to the user to decide which cons he can live with or not.

And why would you want to make stropping unnecessary? It's a great way to keep gouges sharp for example.

 

[Phil Pascoe]

I've never found waterstones any messier than oilstones, in fact the opposite could be said - I'd much rather get a drop of water on my work than a drop of oil, and if you have to wipe oil off you'd just as well wipe water off. I wouldn't dream of using a waterstone for gouges anyway, but for all narrow things I use the side of the stone.
Anyway, each to their own. This subject has been well enough covered before.

 

[Jacob]

I've never found waterstones any messier than oilstones, in fact the opposite could be said - I'd much rather get a drop of water on my work than a drop of oil, and if you have to wipe oil off you'd just as well wipe water off. I wouldn't dream of using a waterstone for gouges anyway, but for all narrow things I use the side of the stone.
Anyway, each to their own. This subject has been well enough covered before.

Water makes tools go rusty.
Oil helps keep them rust free.

 

[Phil Pascoe]

If you wipe them off anyway, they are dry. Dry metal doesn't rust.

 

[bugbear]

BugBear

 

[SammyQ]

Drat. I was going to offer a large wooden spoon, but Bugbear's most excellent animation is miles better...Nice one Paul.

Sam

 

[Newbie_Neil]

Hi BB,

You beat me to it.

Neil

 

[Trafalgar]

Any speed advantage of waterstones is lost through their requirement for frequent maintenance, need for running water in the shop, potential unsuitability for gouges, etc.

As for polishing, there are extremely fine loose powders and alumina slurries that work much better and you are free to customise the firmness of the substrate to your requirements from compressible leather up to very hard substrates depending on the tool being sharpened.

When desired, nothing beats a smidgen of loose AlOx powder on top of a hard Black Arky or maybe diamond paste on the Arky. :ho2

Medium and fine India stones to establish geometry, a hard black Ark, and 50,000++ grit AlOx powder provide polish and refinement; $5 worth of the powder will last several years. If you need to polish gouges and carving tools then throw in a $20 piece of leather. For the total wonk, metal polishes and loose grits are available in sizes as small as .05 micron, much smaller than the .5 micron polishes frequently recommended. These products are cheap and a little goes a very long way. They can also be bought in bulk and shared in a professional shop, school, or amongst members of a woodworking club, for example.

Most of the time the edge off the fine India will suffice, certainly so off a black Ark, and off the charts smooth and refined with the range of powders and polishes available. Your choice. Your judgment. Stop at whatever point suits you and the task at hand.

Everything you need (powders and grits of all types, slurries, suspensions, pastes, diamond sprays, lapping solutions... everything):

https://www.emsdiasum.com/microscopy/pr ... plies.aspx

What's more is that this works on scrapers, router plane cutters, combo plane cutters, carving tools, turning tools, firmer gouges all the little and not so little sharpening jobs, and does it essentially without risk to the stone and without the need for frequent stone maintenance.