Effectiveness of leather strops (and polishing compounds)

[David C]

Jacob,

I was being kind and assuming that you might have something like a hard Arkansas stone.

David

 

[Cheshirechappie]

Something the experimenters might like to investigate is the lasting quality of edges sharpened in different ways. For example, with modern equipment such as diamond lapping films it appears possible to achieve almost insanely sharp edges, but how much service will such an edge give before breaking down? What's the optimum level of sharpness that gives good results with minimum time spent maintaining the edge, and maximum time cutting wood, on different duties?

Karl's point about how sharp an edge needs to be for different tasks seems to me the key point. For example, there seems little milage in sharpening and honing a mortice chisel to the sort of edge angles and sharpness normal for a finish carving tool, as the edge would break down almost at the first whack of the mallet.

In the 18th and 19th centuries, when the only sharpening stones readily available were the likes of Turkey, Charnley Forest and Welsh Slate, stropping on dressed leather (which was fairly cheaply and easily available) was a realistic way of quickly refining an edge. (I've never tried this, but I think you can strop an edge on the palm of your hand; seem to remember this written in one of Charles Hayward's many books.) Now that the technology of sharpening has developed, it would be surprising if no better method of achieving a very fine edge than stropping had been developed. However, that doesn't mean that stropping is dead - it quite plainly worked very well for many craftsmen over several generations, and much fine work was done by them to prove the point; so it will still work just as well.

 

[Paul Chapman]

Karl's point about how sharp an edge needs to be for different tasks seems to me the key point.

But it's not just about sharpness. Very often it's about matching your tools and techniques to the wood. I was planing lots of Sapele today. It was horrible stuff with all the usual reversing grain. No matter what I did I couldn't get a decent finish with my normal planes - just lots of tearout and general roughness. So I got out my scraper planes (the large Veritas and small LN #212) and had a silky smooth finish in no time

Cheers :wink:

Paul

 

[Jacob]

Jacob,

I was being kind and assuming that you might have something like a hard Arkansas stone.

David

I have a black "surgical" Arkansas stone. It's too fine for woodwork purposes. Probably why it's termed "surgical".

 

[Jacob]

Karl's point about how sharp an edge needs to be for different tasks seems to me the key point.

But it's not just about sharpness. Very often it's about matching your tools and techniques to the wood. I was planing lots of Sapele today. It was horrible stuff with all the usual reversing grain. No matter what I did I couldn't get a decent finish with my normal planes - just lots of tearout and general roughness. So I got out my scraper planes (the large Veritas and small LN #212) and had a silky smooth finish in no time

Cheers :wink:

Paul

It's sapele which set me off on the perfect planing hunt. It's not hard all over, quite the opposite in parts, and very crossed reversing grain. Some parts impossible to plane even with my LV la smoother. OK it might have been possible if I'd spent several hours crazy sharpening and then repeating between strokes, but I gave up and bought a Bosch ROS.
My planing did improve a lot during the exercise so it wasn't an entire waste of time.

 

[Derek Cohen (Perth Oz)]

Hi Jacob

I know that you are a professional woodworker and I am a mere amateur .... actually it is because you are a professional woodworker .... that I really struggle to grasp why you want to work with chisels that are not hair-popping sharp (don't take that literally, you know what I mean). The danger of crushing timber fibres rather than severing them cleanly is an ever-present risk. Why would you wish to put yourself in this situation?

Note that despite my hobbiest status as a woodworker, I am not a sharpening hobbiest. I just pay attention to sharpening issues and own decent sharpening media. Perhaps I am too naive to think and work like a professional.

In my experience there is a world of difference in paring, for example, endgrain with a sharp edge, especially in either softwoods or very hardwoods. Dull edges are dangerous as you are required to use more force than necessary. "Sharp enough" in my book is VERY sharp. I cannot get that off a 2000 grit whatever (waterstone equivalent). At least 8000 grit is my target (I generally go to 12000). This usually only requires a 1000 and 12000 stone to achieve this level, and a couple of minutes at most. In terms of time and effort I just do not see what the fuss is about.

Just what do you consider "sharp enough" to be? And how do you determine this in the work you do?

Regards from Perth

Derek

 

[St.J]

Dear all,
I've been lurking here a long time, what a great resource.
It's a bit sad that the first time I've felt able to offer something the thread is about sharpening...

Those interested in the different merits of green rouges (is that an oxymoron?) will enjoy this fabulously geeky post about the granularity of Lee Valley compound: (at this point I tried to post a link but my account won't allow it so try the google search term "lee valley rouge micron consumer alert" and it's the top hit.

I use a hollow grind on most of my edges and then work my way down through three Arkansas oilstones. Because I sharpen freehand this takes very little time and while working I rarely go back to the coarsest stone.
I rarely strop my woodworking tools: plane irons, chisels etc. but do strop my carving tools.

I have two leather strops, one with Boron Carbide paste (1 micron?), the other with Chromium Oxide (0.5?). If the light is angled correctly the surface of the first strop appears shiny. When I take the first stroke it goes black. - dull and perhaps rougher. I believe that this is the very fine wire edge created by the finest Arkansas stone coming off. The next few strokes make the strop go shiny again.

I don't strop my carving tools because it makes them sharper (it might, but after a couple of minutes use who can tell?). I do it because it polishes the bevel and makes them less grippy, easier to push through the wood. And because Chris Pye tells me to :wink:

In short - stropping makes my paring tools seem sharper because they're polished. And it removes the wire edge. I think.

St.John

 

[shim20]

(I've never tried this, but I think you can strop an edge on the palm of your hand.

yep what i do in the palm of my hand, its not as dangeorus as it sounds never cut myself doing it

 

[Jacob]

.........
Just what do you consider "sharp enough" to be? And how do you determine this in the work you do?

Regards from Perth

Derek

It's a question of striking a happy medium between time and effort spent sharpening and the requirements of the job in hand.
If the job particularly requires very sharp edges (clean finishing cuts) then frequent honing on finer stones may be required. Or not, as the case may be - hacking out a mortice and you can go a lot longer between honings. The limit then isn't the finish quality but the force required to make the cut.
In other words - it's perfectly self evident isn't it? Why am I having to spell it out? :lol:

 

[Paul Chapman]

Karl's point about how sharp an edge needs to be for different tasks seems to me the key point.

But it's not just about sharpness. Very often it's about matching your tools and techniques to the wood. I was planing lots of Sapele today. It was horrible stuff with all the usual reversing grain. No matter what I did I couldn't get a decent finish with my normal planes - just lots of tearout and general roughness. So I got out my scraper planes (the large Veritas and small LN #212) and had a silky smooth finish in no time

Cheers :wink:

Paul

It's sapele which set me off on the perfect planing hunt. It's not hard all over, quite the opposite in parts, and very crossed reversing grain. Some parts impossible to plane even with my LV la smoother. OK it might have been possible if I'd spent several hours crazy sharpening and then repeating between strokes, but I gave up and bought a Bosch ROS.

You should have tried a scraper plane, Jacob. No need for any crazy sharpening :wink: I've yet to find a piece of wood with difficult grain that can't be tamed with a scraper.

Cheers :wink:

Paul

 

[Jacob]

...
But it's not just about sharpness. Very often it's about matching your tools and techniques to the wood. I was planing lots of Sapele today. It was horrible stuff with all the usual reversing grain. No matter what I did I couldn't get a decent finish with my normal planes - just lots of tearout and general roughness. So I got out my scraper planes (the large Veritas and small LN #212) and had a silky smooth finish in no time

Cheers :wink:

Paul

It's sapele which set me off on the perfect planing hunt. It's not hard all over, quite the opposite in parts, and very crossed reversing grain. Some parts impossible to plane even with my LV la smoother. OK it might have been possible if I'd spent several hours crazy sharpening and then repeating between strokes, but I gave up and bought a Bosch ROS.

You should have tried a scraper plane, Jacob. No need for any crazy sharpening :wink: I've yet to find a piece of wood with difficult grain that can't be tamed with a scraper.

Cheers :wink:

Paul

I might try it one day. Stanley 80 is pretty good but slow if there's a lot to do.
NB I'm not religiously committed to hand processes, I just like the idea and the results, but in the end it's getting it done wot counts.

 

[custard]

I've yet to find a piece of wood with difficult grain that can't be tamed with a scraper.

Or a 20 degree back bevel...

 

[Jacob]

.....The danger of crushing timber fibres rather than severing them cleanly is an ever-present risk. Why would you wish to put yourself in this situation?

I don't put myself in that situation; I'm not insane. :roll:
If the tool is "crushing timber fibres rather than severing them cleanly" I hone it a bit more until it cuts! Is this the wrong thing to do?
In fact "crushing timber fibres rather than severing them cleanly" defines a blunt blade, which answers your other question.

If an edge "crushing timber fibres rather than severing them cleanly" it needs "sharpening". Just thought I would repeat that for those who don't get it. :roll:
Do you really not get it? is it a wind up or are you all in a trance of some sort? :lol:

 

[Jacob]

........
In short - stropping makes my paring tools seem sharper because they're polished......
St.John

Candle wax has a similar effect, particularly on a plane. It can transform it as though freshly sharpened and set, for just a quick squiggle.
"Seems" sharper is the same as "is" sharper. In other words there's more to sharpening than meets the eye :shock:

 

[David C]

I have a black "surgical" Arkansas stone. It's too fine for woodwork purposes. Probably why it's termed "surgical".

Jacob,

I think these conversations would go better if you did not express your opinions as facts.

Arkansas stones were highly prized by cabinetmakers for more than a hundred years.

David

 

[bugbear]

In the 18th and 19th centuries, when the only sharpening stones readily available were the likes of Turkey, Charnley Forest and Welsh Slate, stropping on dressed leather (which was fairly cheaply and easily available) was a realistic way of quickly refining an edge. (I've never tried this, but I think you can strop an edge on the palm of your hand; seem to remember this written in one of Charles Hayward's many books.) Now that the technology of sharpening has developed, it would be surprising if no better method of achieving a very fine edge than stropping had been developed. However, that doesn't mean that stropping is dead - it quite plainly worked very well for many craftsmen over several generations, and much fine work was done by them to prove the point; so it will still work just as well.

Absolutely - the historical use of stropping exists in a context where Arkansas, let alone waterstones hadn't been introduced. Even when Ark stones were available they were hugely more expensive than a strop.

And for carvers, a slightly yielding strop is ideal for the many curved gouge edges involved.

BugBear

 

[Jacob]

I have a black "surgical" Arkansas stone. It's too fine for woodwork purposes. Probably why it's termed "surgical".

........
Arkansas stones were highly prized by cabinetmakers for more than a hundred years.

David

As were/are many others.
What I'm saying, and having to repeat over and over again, is that the "surgical' sharpness possible with the right kit, is not necessarily desirable ALL the time for ALL woodworkers, and in fact could be counter productive for those wasting their time on creating and maintaining insanely sharp edges, sharper than required for the job in hand.
To which one of the (very stupid) replies tends to be to imply that woodwork which does not require insanely sharp edges is somehow inferior.
Crazy sharpening is particularly unhelpful to beginners IMHO as it sets the fence too high, whereas a simple trad routine with double sided oil stone is good enough for starters, in fact with only a few add-ons is good enough for life!

 

[Philipp]

Hi Folks,

Haven't read all the posts in this thread, so I hope the following has not been written in this thread before.

When grain sizes are being compared to each other it is essential to know how they were determined. Grain size determination can be done by different analytical methods, each giving different results. Even one and the same analytical method, using the same equipment but in different laboratories can give different results.
Also the material itself (i.e. the geometry of its particles/crystals) has a strong influence on the measured grain size.

Certainly, a "10-micron-powder" (whatever that may mean: D100 (haha)? D90? D50?) is very most likely coarser than a "1-micron-powder" (again: whatever that may mean: D100 (haha)? D90? D50?).

But assuming that a powder with a median grain size of, say, 0.5 µm is considerably finer("better") than a powder (perhaps with another chemistry or from another supplier) with, say, 0.8 µm is complete nonsense.

Regards, Philipp (not caring about the digit behind the decimal point)

 

[Jacob]

In the 18th and 19th centuries, when the only sharpening stones readily available were the likes of Turkey, Charnley Forest and Welsh Slate, stropping on dressed leather (which was fairly cheaply and easily available) was a realistic way of quickly refining an edge. (I've never tried this, but I think you can strop an edge on the palm of your hand; seem to remember this written in one of Charles Hayward's many books.) Now that the technology of sharpening has developed, it would be surprising if no better method of achieving a very fine edge than stropping had been developed. However, that doesn't mean that stropping is dead - it quite plainly worked very well for many craftsmen over several generations, and much fine work was done by them to prove the point; so it will still work just as well.

Absolutely - the historical use of stropping exists in a context where Arkansas, let alone waterstones hadn't been introduced. Even when Ark stones were available they were hugely more expensive than a strop.

And for carvers, a slightly yielding strop is ideal for the many curved gouge edges involved.

BugBear

Reality check - Arkansas stone was introduced in the paleozoic era, stropping (and sharpening) has been going on since the paleolithic.

 

[Paul Chapman]

Reality check - Arkansas stone was introduced in the paleozoic era, stropping (and sharpening) has been going on since the paleolithic.

Blimey, Jacob, you must be older than we thought :shock: :lol:

Cheers :wink:

Paul