Hi, I only use the strop to polish the edge after stone sharpening. I didn't think the strop was intended for actual sharpening.

Got a couple issues here. 1. Don't compare abrasives from different manufactures by "grit". Go by the size of the abrasive in microns. For instance, a Shapton 8,000 stone is 1.84 microns and a Norton 8,000 stone is 1.2 microns. 2. You mentioned that the Tormek cuts faster than the red, green, etc paste. There is a reason for that. The Tormek paste is more abrasive. In fact, it has an abrasive of 3 microns. Your 8,000 grit stone is below 2 microns. You're DULLING your blade by using the Tormek paste after your 8,000 grit stone. The green stropping compound is 0.5 microns. And you don't want that on a thick spongey layer of leather. Go for a thin and relatively stiff veg tan leather. Or even MDF or the brown side of a cereal box.

Keep up the great work, Suman. As a neuroscientist/experimental psychologist, I really appreciate your efforts in terms of experimental design, data dissemination, and visualization. You’re carving a lovely niche in the KZfaq woodworking community, and I can’t wait to see what you come up with next!

Awesome video, but I was under the impression that the stropping was an addition to after final honing. I.e. a final polish to remove any nicks. There is no doubt that the the blade is sharp after the 8K stone, but what are the shavings like? Are there streaks on the piece and/or shaving? Can you go straight to finish? I suppose that the edge could be viewed using a jewelers lens, or other means, to see if there are any nicks on the edge that might cause streaking by just using 8k. Btw I don't strop, just finish with 16k stone.

A wise man once told me that stropping " technically does cause micro roundover and I think it makes the edge dull quicker because its a tad more blunt to begin with." So I stopped stropping and it saves me a TON of time! Oh wait! That was you in the comments of your "i don't know why more people don't sharpen like this" video. Your dedication to the scientific process for testing woodworking practices is unmatched! I really appreciate you going through all of the effort and compiling the data in a concise and informative fashion. Mixing these types of videos into the mix with build videos is great. That's one of the things I enjoy about JKM, yet your content is uniquely yours. Keep up the great work!

Stropping : and all others What a pleasure to see the scientific mathod applied to woodworking. Thank you Suman.

I like this guy; been watching woodworking on KZfaq for decades, and it’s rare I see interesting new video topics. Nice work friend!

Hi Suman, great video. I actually did a very similar experiment trying to prove the effectiveness of a strop. In my test, I stropped my blade after 400 strokes on hard maple and the sharpness on my blade went from about 500 to 250 on BESS scale after few stroppings. However, that didn't really last very long. I was back to 500+ range after only about 50 strokes. For stropping to be really effective, I found you need to strop in about every 50 strokes. With this approach I was able to maintain 300-350 sharpness even after 600 strokes.

I love your use of scientific method to demonstrate your conclusions. It isn't just about an opinion like so much in woodworking. I've seen too many times where people present opinion as if it where the absolute truth without data. Very nicely done.

Great video, I really appreciate you taking the time and energy to do this experiment.

I am not a woodworker or craftsman of any kind and I watch all your videos. They’re awesome!

Thank you for being so thorough in documenting your testing methodology. It gives me a lot more confidence in your results that you took multiple test cuts and averaged them, as well as comparing the two blades under identical conditions to give a sense of the natural variability in the materials and the process.

Excellent video Suman. I didn't find it dull at all! I appreciate you putting the time in to show us the science behind it.

Your work and your conclusions impressed me. Many thanks for that! I will stop stropping my chisels and other planer blades, just giving it a test without stropping for some weeks. I love videos like this, with no gimmicks. And yes, you are human (but in a very good sense), like most of us (hopefully). That's another plus.

Extremely thorough, great work!

Very informative! Thanks for taking the time to test and to share! You've gained a new subscriber.

This is very good to know. I am a beginner and from what I’ve watched its always been said to strop. Your video makes better sense to me, thanks for the clarification.

I love this science based woodworking stuff. Great video!

Excellent video and tests. Thanks

Good info. I will have to rethink my methods.

Thanks for all the effort you put into this test! Saves a lot of unnecessary work.

The man who puts the science in woodworking. Nicely done, Suman!

This is like the scientific method’s peer review and pressure testing processes in action for hobbyist woodworkers. Great content with backed up conclusions. I think that the comments pointing out flaws, oversights, or recommendations for improving the methodology have been great. Thanks for putting this together and having the courage to open yourself up to the inevitable trolls to provide the nuggets of good info to slip thru for those of us interested in finding them.

Great video. I had my suspicions about this very thing, which recently led me to switch from my Norton water stones (which require soaking) to diamond plates and Shapton stones (just need a quick spritz). Now, I find it just as easy to touch up my blades and chisels on my Shaptons as it would be to do a quick stropping!

Great job on using the scientific method. I was curious myself about stropping, because I've never used it for my woodworking and always wondered if it really did anything. I'll stick with using the stones.

Great approach and data collection!

Great video thanks for all your effort

Great video with outstanding content. Sharp blades that dull quickly are just impractical. Suman did an excellent job of designing a test that changes what I thought I knew about the benefits of stropping. Going to be retiring my strop and acquiring a fine grit stone.

Rounding over always happens of course due to the greater pressure at the very edge of the bevel, since it is compressing the strop there. But if your stropping angle and pressure is consistent, the pressure will reach an equilibrium where it is increasingly rounded-over as it gets closer to the edge. That is to say, there is only so much rounding over that will happen for a given stropping medium, bevel angle, angle of the edge to the strop, and pressure. This is documented somewhere on the Science of Sharp blog but it is also a pretty intuitive concept. But most people (including me) just freehand strop, so every time we strop to a higher sharpness, well, that bevel gets just a bit more rounded over.

Very interesting! Great video!

Good work, Suman! Thank you 😊

This was super informative! Nice to see some actual data behind recommendations. Now to get an 8,000 grit stone and look into hollow grinding

Thank you for this very interesting video. Although I strop my blades most of the times, I ALWAYS feel like they're duller after doing so, but somehow convinces myself that I must be wrong. This is definitely helpful!

Love the test and you cant argue with empirical evidence. I still strop in my shop and always will. For me it is a factor of convenience. A strop lives on my bench. When my tool dulls i run the blade over the strop a few times and i am back to work. The tool will dull overtime and eventually needs to go back to the stone. Data is great but it is important not to get bogged down in it. If i can still plane figured woods it is good enough. The strop saves me time to function the way i want to function. There are a thousand ways to get to a sharp tool and none of them are wrong! As a side note i dont know what type of leather was used byt horsebutt is the best accompanied with green compound.

i strop often and keep workin. love the videos

Dude- this video and it's scientific aspect has been so helpful!

I use a strop, but not the way you showed here. I refresh the edge by going to a medium stone for a couple passes, then stropping a few times. The method I use allows me to avoid spending money on an expensive fine stone because my cheap strop does the job quite well. Some people have money to burn and they love spending it. People, like myself, prefer to keep as much money in their pockets as possible.

Thank you for the awesome content!

Nice work.

Great job ! I m sticking to my stones !

Ouch! All those years of watching straight-razors being sharpened on a strop.... Never questioned it worked and just kept using the tool. But I always start on a new project at the stone to freshen my tools, and stropped them as I go.

Amazing work!!!!

I'm throwing out my strop right now... You are a hero.

Impressive video for sure. This is helpful for me (newer to the hand tool game) 😊

Great work.

Nice job!

I sharpen on a 1000 grit diamond stone then strop with veritas compound . Maybe there's no difference in sharpness but it takes out all the messing about with different stone grades .

I wish all videos were this good.

Interesting. First of all , thanks for all the effort you put in. I didn't see how you dealt with the back of the blades in your sharpening regime because after teaching many sharpening seminars I see that most peoples blades are ever so slightly "rounded" on the back ( about a 1/32 of an inch behind the cutting edge) I came to realize that like the face/cutting edge the ,back of the blade wears (just to a smaller degree). This can be corrected with a technique popularized by English woodworker David Charlesworth by simply using a very thin "riser" to elevate the blade insuring contact on the back of the blade right at the cutting edge.To the people who complain this introduces a unwanted back bevel I have measured the angle at less than 1/2 a degree and considering I don't use anything coarser than 6000x [which isn't much more than a polishing step] I have been very happy with the resulting very sharp cutting action.

Very impressive presentation 👍

Great video!

Mostly echoing everyone else - I love your approach and explanations. Keep it up! 👍👍

Great video and tests my young friend. Thanks for saving my arm...

Interesting stuff.

Thanks for the great test. I have noticed when I strop on leather that the blade is not as sharp as when I strop on mdf. Don't know how that compares to just stone sharpening...

Interesting, I can see that using a bevel up plane makes any bevel angle change is impactful. Whereas for a bevel down plane it wouldn't make much if any odds (see woodbywright plane iron tests for this). Most people don't strop instead of stones, they strop with stones. So the effort to get the edge back to baseline via a strop is not relevant to most people. Also, if you look at those that are proponents of the stropping method, they are typically stopping at a lower grit stone (circa 1k-1.5k, often diamond plates). So the strop is replacing your 8k, not following it. The bit I can't quite figure out, and bares more investigation is why the stropped blade dulls faster (but starts from the same approx starting level). Normally having a higher angle (which many would agree a strop can create) is more durable, but again, is this a difference with the bevel up plane? Is the higher angle putting more 'work' into the edge as it is turning the wood through a higher angle therefore dulling it faster. Would we see the same in a bevel down plane? Do you feel like a follow up video with a bevel down?

Interesting investigation, Suman. I have experience using a 4 water stone system and a 3 diamond stone and a strop system. Based on experience, the water stone system gave a much better edge. So I agree with the basic premises of your video that it is POSSIBLE to get a better edge on stones. But I much prefer the diamond stone and a strop system. The water stone system is very messy and time consuming to set up and maintain the stones. The average working sharpness of my tools is much better with the strop because I actually use it often vs. avoiding sharpening because of the stone. BTW - I use a 5 micron green bar compound that is roughly equivalent to my 4000 grit water stone. Works for me.

This is some project farm level comparisons here. Good work

Great test and I was surprised by the dramatic results. I have been stropping for decades and have found several things that may improve your results. As many have noted, using a soft leather is very bad. Stropping with wet compound is also counter productive since it leaves the leather even softer and the compound squishes up around the apex. I use diamond powder on thin leather and have found that if I don't let the diamond dry completely before use it will dull my stone honed edges. When the diamond surface becomes loaded and less effective, I give it a spray of water and agitate the surface to bring fresh diamonds into play. When dry, it works like new. Any time I can't get my desired results in less than 10 stropping passes I know I need to do a better job on the stones. Almost all my knives are "super steels" and attempting to strop on anything other than diamond or boron carbide is useless. I suspect V11 is similar (I have V11 plane blades but have always used diamond stropping with them.) Just some observations from a 71 year old woodworker with an obsession for sharp stuff!

Or you could use the strop to clean up the marks from your "1000 grit"/fine diamond stone and don't bother with those higher grits at all. That is what I do and I have patches of handtool pattern baldness on my arms.

I concur with Handlebar Workshops. I also am of the belief that many folk over sharpen... No real need to go past 1200 and a few swipes on the strop to achieve a workable and durable edge. The Old Timers I learned from only ever went to 220 and then stropped... You could shave with their blades. Sure, they resharpened more often, but that isn't a bad habit to get in to really.

Excellent video, that makes me reconsider stropping. How about one on how to sharpen planer blades for the Dewalt 735. I hate buying new blades all the time and haven’t come up with a good way to resharpen them effectively.

Like some of your other viewers, I only strop after sharpening to remove any left over burr if it doesn't get removed using a couple of strokes and the ruler trick on the flat side of the plane blade on my stone, and then it's only between 10 and 20 strokes on the strop.

I think this is interesting food for thought as a place to start. But like many others have said, who only strops their steel? For tools, knives and straight razors, it was always presented to me as a way to polish the edge and straighten out any burr that remained. I don't know one way or another if it's vital for woodworking, but the quality of the feel of the blade on your face is definitely improved by stropping a razor. I'd love to see a comparison between the stone sharpened blade, and one that has been sharpened then stropped. Possibly with some comparison between multiple compounds.

If you made 20 videos a week I would watch all of them, this is awesome!!

This is a fantastic video! Thank you for doing this. From what I've learned reading about the Unicorn Sharpening method the micro bevel can reduce edge damage from chopping impact with chisels. I would love to hear what you think about that. But you've clearly proven it's a waste to strop a plane blade!

Nice!

Tormek honing compound has an average rating of about 3 microns which equates to roughly 8000 grit (the actual grit will vary). The idea of stropping is that the polish you use is a high grit than your last stone. So for anyone who stops at, for example, a fine DMT diamond stone generally rated at 25 micron and then strops with tormek compound, they would see a difference. But people who use ceramic stones up to 16k grit and then tormek compound would actually be ruining their finely polished hone.

should have tried it with finer honing compound. And yes it's normal to strop with 50-100 strokes. But with very light pressure.

Love your videos, your a woodworking project farm in the making!! I use 3/4 MDF and rub my polishing compound on the MDF with a sharpening guide I feel it works much much better than leather

Stropping is something we do after we use stones. Not instead of stones. The only caveat is using a strop to prolong the edge of carving tools. Even then we take recourse to the stones when the strop stops working. This video is a useful illustration that a strop is not made for removing significant wear. It's a refinement step after the stones.

This is so wild!

Very interesting. I'd like to see a few more experienced woodworkers try this setup to confirm or disagree with these results. After all, this is science! Nice video.

Interesting video. I sharpen with a Worksharp so I don’t need to hollow grind. I just give it a quick whizz when it loses its edge. I use a diamond disc in it from China. These are cheap. If the edge gets notched I change the disc to a lower grit initially. For finish I change to a higher grit. I sometimes buff on a bench buffer. It certainly makes it shine. Anything compressible is going to round the edge when stropping. I will stop buffing seeing your results. It’s all logical.

This video show it’s better to use a stone to sharpen and hone. Your collaboration with Johnathan Katz Moses taught us that the media for sharpening is irrelevant. Both excellent videos dispelling some myths. I would love to see a follow up comparing the different methods for sharpening: hollow grind/freehand, flat grind/jig, and convex grind (aka Paul Sellers). Which holds the best edge? Gets the sharpest? Consistently? Speed? Etc.

Very cool video. I usually only use my leather strop on my carving gouges which are more difficult to freehand sharpen on the stones. When I do strop my plane irons (not often), I use a wood/MDF strop with diamond paste. I wonder how that would have fared vs the leather strop. The rigidity of the MDF/wood wouldn't round the edge like the leather did and increase the effective cutting angle.

stropping polishes and de burrs and finely hones the edge. you don't press hard and you swap between side every 5-10 strokes maybe 40 strokes each side and you have a razer edge, IF you edge was continuous and already set by a stone.. white compound isn't as fine as green compound either and you need your leather stiff and glued down to a flat block not like in the movies. you can round over an edge with soft leather because it will push over and around the3 edge of the blade.. also with a 9000grit diamond stone you are way past what many will have, a lot of people use like 400 -1000 - 1200 then strop to razer edge while the stones are for alignment and flattening.

Do you think using compound on a plywood would make difference? I sharpen to 1k grit on a diamond stone and strop. I definitely notice my blade dulls faster when I strop? Otherwise I'll just get an 8k grit plate and ditch the stropping all together.

Will you please test stropping with that green compound directly on a MDF board, a generic glass plate that can be found at a hardware store, one of those engineered flat/leveled tiles/stones, and any other “flat” object that consumers can easily find and see if they produce any better results? It would be worthwhile to see the effects of stropping in those instances and to determine if leather stropping is a relic of the past

Yeh but that mirror finish looks awesome. 😊

Outstanding work! If I were ruch I would buy you a ticket to some of those Japanese hand plain competitions with wide Japanese hand plains. The winner is chosen by measuring the "thinnest " shaving with a micrometer....!! I beleave there are valuable things to be learned here...!! Talk about a different approach! The plain looks like a wooden brick. The plain iron is a super thick combination of hard and soft steel! With adjustments by hammer. Like everything Japanese....there is a deep....deep set of traditions coupled with a myriad of very Suttle details. So .....how about the ultimate combination of east/west. Definitive measurable results investigation......? I believe you are just the guy.... All the best!! just jim

Weird. I haven't seen anyone use only a strop to sharpen. They usually use a fine stone followed by the strop. Does the stropping after stone sharpening make the edge more dull compared with using the stone alone?

This was great Suman! Amazing effort man! Don’t listen to Jon and Scotty. This video will go viral. :)

Great job, I have had the suspicion that stropping on leather might tend to round over the tip of the blade. Based on your results, it's looking that way!

Did you use the 8000 grit stone to remove the foil on the blade after sharpening? Because that's why I strop my blades.

A+ for method, but stropping is never supposed to be without re-honing on a stone. It's not a replacement, the idea is just that you can afford the strop compound more easily than a 16k or 30k grit ceramic stone. You're totally right about the rounding of the edge, which is best counteracts by using very stiff leather that is actually on the thin side--much thinner than the leather in your close up. Mounted to some 3/4 ply, it provides a polishing surface with much less give. Just my thoughts!

You're finding about stropping is different on this video than the one you did later with Katz. Is there a change in the hardness of the strop between the 2 sets of tests? The later tests found a soft leather was bad, but the hard leather worked. And surprisingly, MDF was a failure (and nor explained thoroughly).

Try stropping on a rigid piece of material like MDF or even hard maple. You'll not get the rounding over of the edge that way.

This is interesting because if you watch a video by David W called harbor freight chisel part 2 he buffs the crud out of the edge and it gets sharp and stays sharp. I think he said it puts a super tiny high angle microbevel that is next to impossible to recreate by hand.

It is possible, that 8000g stones, were not available in early life, and the strop was the best option to establish a keen edge. Times have changed and old habits die hard.

Strop is not a substitute for 8000 or higher grit stones. You can get only the polish level of your compound. If the stone is higher grit than a compound no surprise it will produce a better edge. Most people use strops after sharpening on a 1000 grit stone just to save some money by eliminating a need for additional higher grit stone.

Maybe I'm nuts, but would deburring or stropping on the backside of the iron help correct the rounding? Maybe you're doing that but I just missed it? Either way I think that logic would apply to both a sharpened or stropped iron.

Hey, Suman, great information and I have some honing compound for sale now if you're interested! Ha! Question for you. I also have the Veritas bevel-up jack plane like you. I see you have a jack or smoother up on your tool wall. What other planes do you use along with your bevel-up? Thanks!

The Project Farm guy got things sharper using a strop and it didn't get dull faster, so it's possible.

What are your thoughts on using a strop to remove the wire edge that occurs after stone shaping?

Great job on this video, your research paid off . It was so worth it. Thanks for sharing

Suman. Did you stropped also the back of the blade?

Well in knife sharping, I know the terms change as you go up from 1000 grit ( Sharpening ) to polishing often around ( 3000 grit & upwards ). It may seem like semantics but there is actual utility to making the distinction of sharpening, polishing & honing. It's still very interesting that honing's use case clearly doesn't fit the thickness of these plane irons it seems. My guess would be that honing is more suited to thin (As well as extremely acute angled) blades that need realignment & the added strength of a convex edge profile. I think most can envision a traditional straight razor. Its edge will sometimes be visably wavey & can start looking like a miniature saw if you use it on very dry (course) beards. Honing becomes very important but is still supplementary to sharpening. Edit: Some minor eng fix.

Wow ! Reality ! Science ! You go , Man ! already subscribed or I'd do it again. remember , Scissors Sam says " Be sharp "

Hello, Suman; I'll be 68 in few months & I've been able to sharpen all kinds of things for about 40 yrs. But until last year I never used a strop w/ polishing compound. Initially I was pretty disappointed w/ the results. It really does round the edge to strop on leather. To be clear, I've actually stropped knives on cardboard, newspaper, my boot or shoe, my palm even, for years. Just never tried it w/ compound on a leather strop. As stated, pretty disappointed. I got better results stropping w/ compound on a piece of wood than leather. Researching, I found most leather strops are too thick & too soft so that's where it fails. I have a Morakniv "Craftline Basic 511 High Carbon Steel". It is sharper now than when it was new. I strop it on the plastic sheath, no compound. So I agree w/ you, don't waste time "stropping", w/ compound, just sharpen & go. BTW, When I want to get a really sharp edge I finish by 'sword sharpening'. Have a GREAT day, Neighbor!