using a strop

[Jeff Farris]

.... I have seen it mentioned on several carving sites.

Carvers dub their edges because they would rather take a beating than have to reshape their tool. They push the process far past its effective use. They work until the tool isn't performing, then to make the next cut, they cheat the angle while honing and repeat that again and again until their cutting edge is rolled over to the point that their effective cutting angle is in the high 40's to low 50's. That's the impatient carver scenario.

The patient carvers I know hone on leather long before they notice a decrease in performance (as Bob mentioned). They do it carefully and precisely in line with the original bevel. I know some whose tools haven't touched a stone in years.

[Sandy Stanford]

But Sandy, let's say you had your Shapton 8000 grit a few feet away, and your Shapton 15000 right next to it. Wouldn't you return to the 15000 grit stone to re-touch your blade? And if so, why wouldn't you return to a .5 micron "strop" if it were sitting next to the Shapton 8000 instead?

I doubt it Mark because I think there are other important attributes to a honing stone beyond nominal grit size and I think these attributes apply to your scenario since you are essentially using a strop as a honing stone.

I'm not convinced that a haphazardly charged leather strop won't cut serrations (scratches) into the leading edge of a chisel or plane plane. This is the nasal spray analogy again. A serrated edge doesn't cut all that badly but it breaks down making you go back to the strop over and over again. Contrary to another poster's opinion, I think that will inevitably dub the edge and I frankly don't think it takes to many trips to the strop for this to happen.

My question remains - what do you lacking in your finishing stone causing you to feel the need to continue to abrade metal?

[Sandy Stanford]

Carvers dub their edges because they would rather take a beating than have to reshape their tool. They push the process far past its effective use. They work until the tool isn't performing, then to make the next cut, they cheat the angle while honing and repeat that again and again until their cutting edge is rolled over to the point that their effective cutting angle is in the high 40's to low 50's. That's the impatient carver scenario.

The patient carvers I know hone on leather long before they notice a decrease in performance (as Bob mentioned). They do it carefully and precisely in line with the original bevel. I know some whose tools haven't touched a stone in years.

A little 'tooth' is not a bad thing to have on a carving tool either.

[Jeff Farris]

...
I'm not convinced that a haphazardly charged leather strop won't cut serrations (scratches) into the leading edge of a chisel or plane plane. ...
My question remains - what do you lacking in your finishing stone causing you to feel the need to continue to abrade metal?

Then I suggest you not be haphazard in the application of compound.

Let me turn your question around, why buy an $150 finishing stone that is about 1 micron, when you can use an $8 tube of compound that has exactly the same (or slightly better) abrasive properties? If you don't like leather, you can use it on MDF, which for practical purposes is as flat as a plate of glass.

One of the aforementioned WoodNet sharpening fanatics recently wrote me privately that he has close to $5,000 worth of bench stones from the very latest designs from Shapton to quarried Japanese natural stones. Today he uses PA-70 on MDF.

[Sandy Stanford]

I have to agree with Jeff, based on experience and use.

Wear, dubs edges. Stropping might not remove enough material to easily correct this dubbing, but if done properly and regularly, stropping can even slow the dubbing caused by wear. I strop the moment I think the blade is not perfect. Two to four strokes on a side does not take long and keeps tools pretty nice. Paradoxically. the longer you wait between stropping, the more you will dub the blade.

An ideal edge is keen. Such as this side view of an edge on a sharpening surface.



As the edge gets worn down and corrected, and as we rock the blade while stropping or honing, the edge starts to recede from the surface.



In the illustration above, without rocking the blade, or grinding down and eliminating the secondary bevel, sharpening on a hard surface means the edge is not going to contact the sharpening media. If you rock the edge, you are as likely to shift the angle even more and this will accelerate dubbing.
If you are sharpening and sharpening and not getting any results, then this is the probable reason, and you need to regrind the edge to true before you can make the edge keen.

A somewhat flexible media, used with a gentle touch will allow for this, without requiring an increased angle. If you strop with an increased angle, you will accelerate dubbing, if you push down hard, you will accelerate dubbing.

Oddly enough a touch of dubbing is not such a bad thing. It strengthens the edge. A dubbed edge can still be keen. The problem is that as it wears down, eventually you will need to either bear down (heaven forbid) or start to shift to a higher angle in order to contact the actual edge and return it to keen.


The effect of stropping and wear in combination could be considered similar to a micro-bevel. A fairly obtuse edge can still cut fibers, as long as it is keen. If you look at the illustration above and think of it as a dubbed blade in use instead of a stropped edge, you can see where wear on a well stropped, slightly dubbed blade, can to a certain degree correct the previous wear damage.

Wear caused by use, combined with regular low pressure stropping at low or no angle, can allow you to continue using an edge for quite a long time. Proper stropping means contact with abrasive, but no strong distortion of the blade or edge. The actual abrasives involved are tiny, so the pounds per inch of force applied as the abrasive drags across the blade can be quite large despite the gentle touch being used.

If when you strop, you stroke the edge more side to side than you drag it base to point, you will tend to produce a smoother, more unified edge and therefore keener edge.

If when you strop, you find yourself needing a higher angle to get results, then it is time to hone or even grind your blade back to true.

Ideally you want a hard, flat slab of leather for your strop.
If you take a section of vegetable tanned leather, preferably horse butt, wet it and then let it dry to the point where it still feels cool and damp, but looks dry, then you can compress it between two flat plates in a vise and turn it into a very hard smooth leather surface. Hammering, at this moisture level, was the traditional method to compress leather for making shoe soles, but this can give an irregular surface that will need to be sanded down before used on a strop. After this drys completely, this can then be glued to a flat board with the flesh side up. The smooth skin side is ok, but the rough textured side is preferred for stropping.

Plain, ungritted leather will strop to as fine an edge as you might want, but will not be as fast as a strop that has been treated.
With fine monocrystalline diamond grit, working it into the leather while it is still wet will make for a faster strop that will hold up a long time. Rubbing a good honing compound on the surface also works wonderfully. I keep my strop barely supple with some non-drying oil. Camellia, olive or Ballistol all work well for this.

When using a strop after you hone, to remove feathers, you should start out flat on the strop with pressure just hard enough to maintain even pressure. The term 'kissing the leather' is pretty much dead on. Raise the angle a bit as you discover the feathers are not coming off. The higher the angle, the more dub, but the faster the feathers are removed. So you want the lowest angle that will flex the feathers enough and wear the feathers base enough for them to come off.

After the feathers are gone and you are touching up the edge, start out stropping with the bevel flat against the strop, take about four strokes on each side and test the edge. If it is not sharp enough, then raise the back of the blade a bit, take four strokes on each side and try again. Once you find the right angle stropping should be pretty fast. Almost all of my blades will sharpen fine, flat on the strop. A few seem a bit more resistant to stropping and need a higher angle. Some only need a couple of strokes to get back to a keen edge.


All of this said, it is very hard to beat a fresh bit of unadorned and untreated vegetable tanned tooling leather for stropping. Just lay it on the table flesh side up and a few gentle even strokes with the flat of the bevel parallel to the leather. This is how I take care of my leather working tools, and they stay wicked sharp. I think the original skin, and perhaps the materials used in tanning put enough of a polishing agent in to allow for a pretty good strop, at least until those materials wear down.

Bob

I strop bench plane irons and bench chisels on uncharged leather purely to remove rag and remnants. I use oilstones. My finest finishing stone is a Black Ark.

If I used high grit papers regularly (I have used them extensively enough) or owned fine grit hybrid ceramics I would not waste my time stropping. I would simply go back to the paper or my ceramic finishing stone. As it is, I go back to my Black Ark because my strop is not set up to abrade. If ever I felt I wasn't getting what I needed from my Ark set up I'd buy a finer stone and the Black Ark would become a 'next to last' stone. I wouldn't use a strop as a proxy for a stone when there are better solutions than doing so.

Simple as that.

As I said in an earlier post, stropping has value for carvers. But the OP is not a carver apparently.

[Jeff Farris]

A little 'tooth' is not a bad thing to have on a carving tool either.

I know several thousand carvers who would wholeheartedly disagree with you on that.

I'm also not sure where you're coming up with this "tooth" concept. While the article you linked early in this thread mentioned toothy edges, that was in comparison to .5 micron micro-finishing abrasive paper. It was also using compounds that I'm not sure how he chose, but they weren't enlightened choices.

Sandy, I think what a couple of us have tried to point out to you is that there are many paths to a properly prepared edge, not just one. If you don't like to hone with compounds, then don't, but you came on a little strong in the beginning of this thread, comparing compound honing to sugar pills. As the day is waning here, I took my copy of Thomas Lie-Nielsen's sharpening book off the shelf and was glancing through it. I also spent several years working beside Deneb at the Woodworking Shows and discussing sharpening techniques. If high polish is the goal, and I certainly think it is, then looking at TLN's book and Deneb's work, I will stick to leather and compound and/or MDF and compound.

[Kevin Adams]

Thanks for your thoughts, Jeff. I've been happy with PA-70, but was just wondering about something finer. Diamond paste would be even more expensive and you will run into the same cost:benefit scenario.

Kevin

[Jeff Farris]

... but was just wondering about something finer.
Kevin

Can I ask why? If you're not getting a mirror (and I do mean mirror) polish, let's figure out why.

[Bob Strawn]

As I said in an earlier post, stropping has value for carvers. But the OP is not a carver apparently.

Good carvers like good oboe players know sharp. Their tools vary in bevel angle, curve and skew. They do detail work in pine where every other curve is more endgrain than not. A good carver must know leverage, deflection, grain and patience. If you are doing detail work, crunched wood is no good. A carver may wail out their work a bit at the beginning of a project, but details pop off if their tools are not dead on sharp. Take a look David Calvo's work and imagine doing it will dull tools.

I personally use a lot of methods that Brent Beach has detailed. I have learned a lot from him. I agree with most of his points.

Two years ago, I would have argued that a strop was an inferior method. I find that loose grit on a steel plate is amazing fast, inexpensive and elegant. Diamond dust bedded into steel by hand pressure is amazingly versatile and can be used to sharpen in ways that almost nothing else can. These are both websites by me, so they serve to illustrate my dedication to these methods.

However my motto is, 'I would rather look stupid today, than be stupid tomorrow.' So I make sure to examine everyone's methods to be sure I have not missed something. When I studied old fashioned shaving, I found out that they still liked strops. When I studied carving, I found that they still, despite all the advancements in technology, liked strops. When I studied leatherworking, I found out that a lot of leatherworkers don't have strops. They need sharp tools to make nice cuts in tough leather, but a lot of them just use the untreated leather they are working, as they go. No need for a special strop or paste.

So I started practicing and playing with strops. I made quite a few strops using wood.


And I made quite a few leather ones charged with 0-0.25 micron monocrystaline diamond dust.

Over time I learned that I could put a blade back into top end service faster and more easily with a strop than I could with a nice stone, a honing guide, even a belt sander or sharpening wheel. I can carry a strop with me, and use it in the field. I can tap out the blade on my Japanese smoother, touch up the edge, and then tap it back into position to make transparent shavings in less than a minute, and I did not need oil, stones, water or even spit to do it.

I can keep doing it over and over, and unless I have damaged the edge of the blade on a miserable knot, I don't have to pull out a stone or take a lot of care and time to sharpen. More importantly, I am removing the minimum material from the blade. Best of all, this is easy to learn.

Bob

[David Keller NC]

But Sandy, let's say you had your Shapton 8000 grit a few feet away, and your Shapton 15000 right next to it. Wouldn't you return to the 15000 grit stone to re-touch your blade? And if so, why wouldn't you return to a .5 micron "strop" if it were sitting next to the Shapton 8000 instead?

While not addressed to me, I can (sort of) comment on why I, and other carvers I know strop their edges rather than going back to a stone.

Particularly with a plane blade, it's one whole heck of a lot easier to strop the edge than it is to go back to the honing stone, particularly in my case since I'm using waterstones and I don't store them wet.

But while this discussion (argument?) is academically interesting, I still think it's a distinction without a difference. One pass of the newly sharpened plane down a hardwood board will render defects in the edge far larger than the difference between a freshly honed or freshly stropped blade.

[Jeff Farris]

Bob,

Thanks for sharing the link to David Calvo's work.

Here's another carver whose work is inspiring, to say the least.

http://davidesterly.com/

[george wilson]

I know a professional life long harness and saddle maker now 75 years old. He says that getting leather knives too sharp is not the most useful thing to do,as cutting the leather quickly removes the super sharp edge. So,he doesn't strop.

This is in reply to the post above that mentions stropping leather tools.

As for loose diamonds,I am very leary about letting loose diamonds possibly contaminate something in the shop-like my metal lathe,etc.. I use diamond stones where the diamonds are trapped in a nickel matrix. Even then,though,I am careful about throwing any wipes used on them into the trash after using them. The trouble with diamonds is that they last a very long time if you get them on any precision sliding surfaces that they somehow land on,turning them into laps.

[Bob Strawn]

I know a professional life long harness and saddle maker now 75 years old. He says that getting leather knives too sharp is not the most useful thing to do,as cutting the leather quickly removes the super sharp edge. So,he doesn't strop.

This is in reply to the post above that mentions stropping leather tools.

As for loose diamonds,I am very leary about letting loose diamonds possibly contaminate something in the shop-like my metal lathe,etc.. I use diamond stones where the diamonds are trapped in a nickel matrix. Even then,though,I am careful about throwing any wipes used on them into the trash after using them. The trouble with diamonds is that they last a very long time if you get them on any precision sliding surfaces that they somehow land on,turning them into laps.

I think you are wise to have a healthy fear of loose diamonds. They can migrate like invisible grease. When using fine diamond on steel, after a while the grit beds into the steel and makes for a nice sharpening surface. This can be washed off and the diamonds that have bedded into the surface will remain and will function wonderfully. So I use different surfaces for different grits. When working through grits, if you don't clean and wipe down the tools you are sharpening, it is pretty easy to move course grits to finer grit beds and thus ruin them for fine work. I waste a lot of napkins when I am doing diamond work. So while I love diamond grits, I am very careful with them and wear disposable gloves so that my hands don't become vectors of tiny abrasive dust.

Fine aluminum oxide is not as bad as diamond, but it can still be pretty horrid. One time I foolishly decided to polish a cedar workbench with fine aluminum oxide and it bedded into the surface. The only way I found to remove it was to use a scraper. It was an amazing amount of work, since aluminum oxide bedded in cedar is ideal for removing a bur. A few good strokes and It stopped being a good scraper. Fortunately a few more strokes would clean up the scraper and make it ready for burnishing. But I spent as much time burnishing as I did scraping.

On the plus side, eventually the diamonds will probably round off and become nice low friction protective studs on a surface. At least l hope they will. Since diamonds slowly evaporate into the air, I wonder if the really small ones will eventually become sharper, kind of like a file in vinegar.

Bob

[Sandy Stanford]

Good carvers like good oboe players know sharp. Their tools vary in bevel angle, curve and skew. They do detail work in pine where every other curve is more endgrain than not. A good carver must know leverage, deflection, grain and patience. If you are doing detail work, crunched wood is no good. A carver may wail out their work a bit at the beginning of a project, but details pop off if their tools are not dead on sharp. Take a look David Calvo's work and imagine doing it will dull tools.

I personally use a lot of methods that Brent Beach has detailed. I have learned a lot from him. I agree with most of his points.

Two years ago, I would have argued that a strop was an inferior method. I find that loose grit on a steel plate is amazing fast, inexpensive and elegant. Diamond dust bedded into steel by hand pressure is amazingly versatile and can be used to sharpen in ways that almost nothing else can. These are both websites by me, so they serve to illustrate my dedication to these methods.

However my motto is, 'I would rather look stupid today, than be stupid tomorrow.' So I make sure to examine everyone's methods to be sure I have not missed something. When I studied old fashioned shaving, I found out that they still liked strops. When I studied carving, I found that they still, despite all the advancements in technology, liked strops. When I studied leatherworking, I found out that a lot of leatherworkers don't have strops. They need sharp tools to make nice cuts in tough leather, but a lot of them just use the untreated leather they are working, as they go. No need for a special strop or paste.

So I started practicing and playing with strops. I made quite a few strops using wood.


And I made quite a few leather ones charged with 0-0.25 micron monocrystaline diamond dust.

Over time I learned that I could put a blade back into top end service faster and more easily with a strop than I could with a nice stone, a honing guide, even a belt sander or sharpening wheel. I can carry a strop with me, and use it in the field. I can tap out the blade on my Japanese smoother, touch up the edge, and then tap it back into position to make transparent shavings in less than a minute, and I did not need oil, stones, water or even spit to do it.

I can keep doing it over and over, and unless I have damaged the edge of the blade on a miserable knot, I don't have to pull out a stone or take a lot of care and time to sharpen. More importantly, I am removing the minimum material from the blade. Best of all, this is easy to learn.

Bob

I think the differences between honing carving tools vs. bench planes and chisels is more than nuanced. There are a whole lot of differences in play. I appreciate the information you've conveyed here but it's not necessarily on point with maintaining the simple geometry involved with bench planes and chisels, and whether stropping those two classes of tools is even necessary when a very fine finishing stone has been acquired and is available for use.

[Callan Campbell]

Then I suggest you not be haphazard in the application of compound.

Let me turn your question around, why buy an $150 finishing stone that is about 1 micron, when you can use an $8 tube of compound that has exactly the same (or slightly better) abrasive properties? If you don't like leather, you can use it on MDF, which for practical purposes is as flat as a plate of glass.

One of the aforementioned WoodNet sharpening fanatics recently wrote me privately that he has close to $5,000 worth of bench stones from the very latest designs from Shapton to quarried Japanese natural stones. Today he uses PA-70 on MDF.

"Very Privately", so that his wife didn't read his post[5K in sharping equipment]