Does Dead flatness Matter

Not really, but it’s just a reference face and we generally need something to shoot for. What is funny is that those advocating this thing called dead flatness are the ones selling all the gear and the sooner the support gear wears out the sooner you are back for the next batch of abrasive paper, film or whatever cuts steel to the fine edge you want. Gluing abrasive to a dead-flat glass plate or granite works but then you must remove, replace, clean off and reglue more abrasive paper to keep the flatness without bumps that you need. Sheet abrasive of almost any kind will do the job and is fine to get you started but it’s not nor should it be a long term sharpening solution to sharpening. Not only will it prove the most expensive option if prolonged over months and years, but it’s also more the impracticality that may well not be so evident at first. in the start out, if you’ve accomplished sharpening a tool at least, then that can be enough appeal alone. Ultimately, what you want and need is the immediacy of sharpening. Don’t be misled into believing that sharpening an edge means the edge will last for hours of use. Mostly it won’t, in fact, it might well be a matter of minutes before you must return to the abrasive. That being so, better to choose an abrading system that will not need such constant replacement. Oh, and don’t fall for hyperbole titles like “scary-sharp” systems. It was and always will be silly. Any and all abrasives will give you the same level of sharpness and so too any bevel of between 25-35 degrees will give you the edge you need whether it is micro- or maxi-bevel or anything in between; believe me.

This white line at the cutting edge shows the edge fracture that occurs soon after starting to use the plane.

Please remember that just about all magazines are primarily supported as media companies charging advertisers for adverting their wares and then too expecting the magazines to actively promote what they make be that a gardening magazine selling hosepipes or woodworking magazines promoting power routers, fancy table saws, and bandsaws. You get what you pay for and what you are paying for is at least 50% of the pages dedicated to the advertisement of stuff. At any and all woodworking shows, stores, etc it is the same. The ones pushing the planes are sales staff and not experts in anything more than making that plane look good for a few minutes. It’s at the workbench in your workshop where the rubber hits the road.

A newly sharpened edge shows no white line because light cannot reflect off a sharp edge.

I have watched the gurus you may well know and watch spend a good hour setting up the equipment to make them and their equipment look good in front of the audience. Anyone and everyone can make a plane cut any grain in any wood for a few minutes. In the reality of benchwork is where it all matters. These artificial environments are really quite unreal and not at all part of my world whether teaching or making. In my world, a plane needs to go from dull to sharp, reinstalment and reset in under three minutes. Anything else is totally unacceptable. I know, that’s just me, but its the woodworking that is the most important to me. What helps me to achieve fine woodworking is a crisp sharp edge. I might sharpen 20 edges in a given day. I can’t give up 10 minutes just to remove abrasive from plate glass or even have baths for slopping stones around in. Sales staff can be great actors after a few days of selling and then they can come across as really experienced in the field. I know a dozen or so of them and as it is with most people in sales, what matters at the end of the day is how much they sold. Not cynical, reality. I know some who 20 years or more ago did little more with wood than set up their sales pitch to sell planes, chisels, saws and such at the show venue and then pitch to the public. Nothing wrong with that at all. But that made them experts and in the land of the blind, the one-eyed man is king. That began their careers as experts selling on the show floor not really experts in the zone of woodworking.

Creating the penultimate flatness takes some sophisticated equipment at Lee Valley Veritas.

Back to the point. Dead flatness needs rarely if ever be as flat as people say or we might believe we need. Often the ambition is beyond possibility for several reasons not the least of which is having the right equipment. Visiting Lee Valley Veritas in Canada to see how their tools are made made me realise just what it would in fact take to achieve a truly flat surface. Their equipment is very sophisticated and their standards are very high to match.

Recalibrating equipment to optimize machining is highly skilled and maintaining standards is all part of Veritas and their output

In fact, it is almost impossible for anyone with the kind of equipment we have access to use to get a meeting face to a bevel truly dead flat. That fine edge is indeed crumbling even as we sharpen, albeit very fractionally, and perhaps to a level that the edge fracture cannot be seen by the unaided eye. The larger the abrasive you begin with the more the leading edge will indeed rounded by fracture caused by the particulate itself. Our reducing the particulate size in step-down abrasive sizing helps. Of course, it does. But no matter, it still results in the leading edge appearing slightly rounded but rounded it is, by degree at least.

I elevate the chisel two degrees or so to optimise its presentation for the best cutting ability

The two areas we generally look at for sharpening are plane irons and chisels. Most of us do not use draw knives and the spokeshave is a plane with side handles instead of inline totes anyway. All planes offer the cutting edge of the iron at an incline anyway. Never is the flat side against the wood as such. Bevel-up, bevel-down, all plane blades present the underside face if the cutting iron bevel or flat at an angle between 12-15-degrees. Few might realise there is so little difference between the two plane types. Also, as a practical issue, these edges fracture ALL the time. Mostly it is edge fracture not wear that turns the edge from crisp sharpness to unusable. The longer you procrastinate the more work it takes to get nearer to the sharp edge again. This breakdown of quality is in your hands. I rarely wait until the edge is dulled for more than a few strokes if I even get a hint of being near to that point. Perhaps this will give you an idea of why paper and film abrasive is not really a long term solution for the total sharpening option.

OK. The conventional bevel-down plane held by lever caps with cap iron (not really called chip breakers because they don’t break chips) sandwiched in between need not be dead flat across the large underside flat face of the cutting iron. Why on earth would anyone say such a thing? Well, with good reason, I do and always will.

This assembly shows the gap snugged up with finger and thumb until the two parts meet…
…whereas this image shows the take up of the gap just with and extra two turns with the fingers and not yet with the screw fully tightened by a driver. I think that is remarkable and shows how both the cap iron and cutting iron physically bend against one another. that being so, why flatten the cutting iron at all?

The relationship between the cap iron and the cutting iron is critical to bevel down planes with thin irons, even if the thin irons have indeed been replaced with so-called thicker irons. Cutting the side off a plane helped me to see the reality the power of the lever on the lever cap had at this critical juncture in the plane iron assembly beneath it. The lever at the top of the lever cap is powerful. Pressing the lever from open to close is a transfer issue whereby the foredge at the lowest point or edge of the lever cap applies force along the hump of the cap iron that in turn applies pressure along the whole of the flat face of the cutting iron to press it wholly to the leading edge of the rear part of the plane’s sole a d then too the lower area of the bed of the frog right up as close as possible to the cutting edge of the iron.

Lever cap open releases all pressure at the forend of the cutting assembly
Locked down, the pressure transferred to the cutting assembly forces the edge and takes out any resistance to flatness
Notice that the rear of the cutting iron by the bevel edge sits tight against the sole fore-edge.

Even if the cutting iron was twisted, hollowed or bellied by a great amount, which they rarely ever are, it could not resist the pressure to conform to the frog by the single pressure from the lever on the lever cap. If the frog is flat along its width by the leading edge, the blade will end up flat too. On bevel-up planes, the fore-edge of the cap is forced down by applying pressure via the knurled bolt and the reverse cantilever that pivots via the central setscrew. Again, the force you apply easily conforms a twisted, bellied or hollow iron to the mating surface.

Now on chisels. Whereas I might admit that a dead-flat face is of some value, that is rarely essentially the case in terms of using them and actually it is as I said earlier, rarely possible for anyone with the kind of equipment we have access to use to get a meeting face to a bevel truly dead flat. That being so, we should rethink why we actually need the chisel to be so dead flat. Let’s say that 50% of chisel work is chopping and the other half is paring. In both cases, dead flatness is not really needed. Experience through the years tells me that we constantly micro-adjust the presentation of the chisel to the task by what we feel and see as we use it.

Normal work is undertaken by raising and lowering the handle end until the chisel bites. Very rarely do we need a chisel to pare when it is level with the surface of the wood. We create the cutting dynamic by equalling out the top and bottom pressure as we push the cutting edge into the wood be that with the grain or across it. Whereas we may well pare a plug level to a surface, even in this we rarely can without elevating the handle a degree or two to equal out the pressure above and below the cutting edge to effect the cut evenly with pressure to the top and underside. If that is the case, and it is, then let’s just aim for flat without sweating it.

Chopping mortises or recesses for inlaying wood or hardware is really the same. No need for dead-flatness here either.

Let’s break out! Take a step away from legalism and just enjoy sharpening to near enough. Rethinking from my youth and watching skilled men just sharpen up and get on with their work was magic. We can have that too. If you do enjoy extensive methods for sharpening though, just carry on. As long as you enjoy it what does it matter?

53 Comments

  1. There a few out there, that think a plane’s sole MUST ground flat, by a surface grinder, at that…..And they seemed to think any “Vintage” plane sole HAS to have been warpped out of flat….and NEEDS the flattening to make the sole perfectly flat. same people also charge $$$ to provide this service…even to a Stanley No. 110 block plane. They also claim mere sandpaper will only make things worse..

    Then there are the 16,000 grit sharpener people, who seem to think a highly polished bevel and back will make the perfectly sharp edge….remember this..you can get the same mirror like polish on a butter knife..it it will barely cut warm butter…

    Soles? I use the 2 finger test….one finger at each end of a plane’s bottom casting….press down with the tips at the centerline, and at diagonals to each other…does the plane rock? No? Put the plane to work, making shavings.

    I sharpen to 2500 grit, then the strop…and can pull see-through shavings….with just a simple 25 degree bevel. Flat back is merely to keep the shavings from getting stuck under the chipbreaker, nothing more.

    1. Flattening the sole of the plane has little if any effect. If you think what happens when you plane the wood behind the blade is lower than that in front of the plane therefore that part of the plane if flat does not touch the wood. The only parts of the plane that touch the wood one the plane is fully on the work piece are just in front of the mouth and the extreme end of the heel. There is plenty of evidence to support this – hard used planes develop a hollow just in front of the mouth as that is one of the two contact points. This needs to be removed eventually. You can simulate what happens if you put a piece of wood a few millimeters thick under the front of the plane, just in front of the mouth and seeing what touches. Of course you don’t take cuts several mm deep with a hand plane so this does not normally show as clearly. The other piece of evidence is to look at the design of a hand power planer. Here the front of the plane is raised by the depth of cut – indeed raising the front of the plane is how you set the depth of cut on a powered planer. In the case of a power planer the wood should be in contact with both the front & rear part of the sole.

    2. You can’t have a plane sole look like a banana, but dead flat is a fool’s errand. As soon as you grip the plane the sole flexes, even if it is a thou or so.

  2. This is interesting and makes perfect sense …NOW. See I bought a Buck Brothers jack plane about 30 years ago at home depot. I could never get it to work right. Even with the iron razor sharp. Well a few years ago after watching your youtube video on restoring a plane, i decided to try it on the Buck plane. What it was was the frog and mating surface were both spray painted so the frog had 2 thick layers of runny enamel between, so it rocked and never really sat right. Scraping all the enamel off showed me that the casting was pretty bad too. I had to file the surfaces flat. Once this was done i was finally able to get it setup and working right for the reasons you mention here.

  3. There is a certain satisfaction obtained from flattening plane soles, irons, and chisels beyond what’s really necessary. Especially when you’ve spent a long time restoring rusted, neglegted, useless hulks to workable tools. Often beyond what the factory ever cared to do.
    A mirror finish on the back of a chisel for example, says; this is the best it can be, I value my tools, and as the new owner I take pride in their looks as well as their function.
    I don’t disagree with the points you’ve made, just saying, aiming for perfection can be satisfying too. Especially when starting out with secondhand vintage finds which were covered in crud & paint flecks. It’s hard to stop when you see the results.

    1. I’m totally the same. On occasion, I’ll spend way more time that is useful getting a tools as flat as I can. There is certainly some satisfaction here. That said, I’ve move on from feeling I have to be constantly grinding on everything perpetually!

  4. Lets see…picked up a handplane Friday afternoon…part of a me day shopping trip. plane was large, and heavy….couldn’t see any real defects….except someone had painted everything but the sole and the wood handles an ugly maroon colour….$22.50 + tax. brought it home..wire wheeled the ugly paint off. Re-paint areas black that were supposed to be black ( most was flaking off, anyway)

    Lever cap was cleaned of maroon paint….iron did need a good sharpening…had almost as many nicks as I get shaving me beard…..took a while that evening.

    2 hours of work, counting the sharpening…this Millers Falls No. 15, type 3 was giving out see through shavings….in Ash. Did NOT have to do a thing to the sole ( passed the 2 finger test) and sharpening and fettling did not take the hours of drudgery most complain about….
    I think I might find some use for it….same size as a Stanley #5-1/2
    Plane was made between 1941 to 1949…..

  5. “Mostly it won’t, in fact, it might well be a matter of minutes before you must return to the abrasive”

    I am SO relieved to read this. One year into amateur woodworking. Sharpening after sharpening I was finally able to get pretty sharp edges. The thing is, I couldn’t figure out what I did wrong because my planes got dull kinda quickly. Maybe 5 min into flattening a board : dull.
    This was very frustrating because I had to put out the stones and strop again. So much wasted time.

    Turns out it is normal. The solution is not some magical skill or tools but simply to have the sharpening stuff at the ready anytime, somewhere in the shop.

    1. I’ve been using hand tools for several years, but have nothing like the level of expertise of some of the folks here. This said, five minutes of working time doesn’t seem right to me. How long my plane irons can go between sharpening sessions varies greatly on a range of factors. For example a nasty knot in otherwise soft pine can have me back at the stones in less than five minutes. For the most part, however, I get much more than five minutes of very good working time. Again, as example, I’ve been working on a large set of bookshelves. I’m using commodity yellow pine. I find I can get through flattening both top and bottom of three 10 inch by 30 inch shelves without going back to the stones. At my level of skill, flattening three shelves equates to upwards of 2-3 hours of work. I do use more than one plane during this time. I start with a modified jack that is tuned for hogging off material. I then use regular jack and longer no 7. Even so, under normal conditions you should get more than five minutes of useful time in most circumstances. I also know that early on, I would have days where it would seem tools would go dull almost immediately. I expect it was something in my sharpening technique.

    2. Simon, whenever you watch Mr. Sellers work at his bench, you’ll see him reach around the left end of his bench to the shelf he installed there especially to hold his sharpening “Stones” and assorted gear. Just another example on how planning ahead can save you steps, time and trouble. (Of course adherence to, “A place for everything and everything in its place” is a bit more difficult for most woodworkers.)

      1. a place for everything is my rubicon… everything I ain’t using is on my bench, somewhere! lol
        sometimes I spend colorful minutes looking for that tool I just had in my hand…

        1. A phascinating philosophical phacet of woodworking to be sure. One needs to consider two places for every tool – the place where it is intended to be and the place where it actually is. The problem is, I really really have to work very hard at keeping those two places coincident. 😀

  6. I’ve spent my share of time playing with (and repairing) 3D-measuring machines in a conditioned measuring room, fooling around with optical flats counting fringes under monochromatic light and lapping stuff. Nearly fell off my chair watching the images you posted as I associate those manufacturing and metrology techniques with very different fields (building parts for wafer steppers, for example), not with woodworking tools…. I suppose the next logical step would be using laser-interferometry.

    All I can say is that if you value flatness *that* much, you’d better have a conditioned workshop that you keep at exactly 20C too, because at any other temperature, the things that were flat at 20C will cease to be flat. And make sure that you don’t hold the plane with your bare hands as the local heating of the casting will distort it. You have mentioned ‘flex’ in metal planes before but it wasn’t until I did a quick test myself I became aware of just how much of it there is in a metal plane. Just thinking how craftsman in the past, without such ultra-flat tools, managed to build impressive things is convincing enough for me that it’s all a bit over-the-top.

    Sometimes people tell me they only want the best in tools/things. I usually respond that ‘good enough’ is fine for me. Optimizing vs. satisficing.

    I appreciate the ‘scary sharp’ method because it was the first (and, basically, only) method with which I could get repeatable good sharpening results. The downside is that it takes a lot of time to set up and sharpen a tool. So sharpening gets postponed to the end of the day when the work is finished. Not good. Am trying to learn sharpening using a basic stone, with mixed results. So I give the sandpaper method credit for that, but it’s beginning to become a limitation to me now, along with all the jigging. “I’ll just quickly sharpen up before I continue” isn’t something I find myself saying.

    1. This is a great response. I don’t the same sort of work as this gentleman, but similar thoughts occurred nevertheless. Go talk to a metal working machinist and explain that you are a woodworker and want to talk about tolerances. You’ll learn all sorts of things. What is flat or precise means different things to different people. I personally can’t imagine that working with wood, I’d ever need to have work pieces closer than plus or minus a few thousandths of an inch. For the metal machines this soft of tolerance would border on sloppy. With wood that that expands and contracts and swells and is compressible and etc you just are talking about something where your tools need to be within 1/10k of an inch perfect. After all, folks back in the 18 century built stunning pieces working with chisels that some dude made by beating on metal with a hammer and then filing it to close to flat. They also did a lot of work with wooden sole tool that are going to be plus or minus a bit based on whether it is a hot or cold day. So yeah, I get obsessive like the next guy sometimes when flattening a tool, but I do try to keep it in perspective.

  7. I’m getting better at sharpening and now see I should be doing it more often. But I could use help with 2 things I haven’t nailed down yet. 1 is rounding the corners of the cutting iron. What should they look like? 2 Preventing shavings from getting stuck. Thanks

    1. Paul, I could not agree more with your description of salesmen. Most are not bad folks, but allot of them are selling solutions to problems I did not realize I had. Over the years I tried several different “sharpening systems”. Most had a single task they could perform, some even adequately, but rarely did they achieve all of the promised results. None were very long lived. I am very happy with the results I am getting from my stones using your methods. We are very lucky to have the benefit of your wisdom. Thank you for sharing it with us.

    2. about shavings getting stuck… you don’t go into detail, but often the cause is a gap between the plane iron and the cap iron where they meet. take them out, tighten the screw and take a look between them from behind, up against a light. you shouldn’t be able to see any gaps

      if you can, flatten the back of the iron and the edge of the cap iron where they meet. Paul shows you this in his youtube video about restoring a #4 plane

      hope that helps

  8. The best thing I did when first sharpening my tools on site was to build a robust wooden box for the two sided oilstone to replace the cruddy foam box so it didn’t get contaminated or damaged. Over the years due to what was at hand everything from wd-40 to kerosene to handy oil etc has been used if something went missing or ran out. A piece of old leather belt was added used with an auto sol polish or compound to strop. If a nail or some other fastener did the disservice of nicking an edge badly the belt sander was used for a fast grind (without the bag of sanding dust attached). I sharpen pretty much as Paul does with the diamond plates etc in the workshop but the oilstone on site is compact , relatively cheap and effective. The twenty odd years of practise help too. The biggest bugbear in Perth is the sand which manages to pervade everything to some degree .

  9. Some of these comments remind me of the Rick and Morty episode where “Morty experiences true level”. You can find the excerpt on youtube. Strong language warning

    1. Just watched it. That was my first introduction to that cartoon which I’ve heard of many times but not watched. Thanks for the laugh!

  10. I’ve seen articles written by so called experts about how the abrasive Ive always used when stropping my edges gets into the micro grain of the blade.
    Of course an expert is defined as a “drip under pressure”.

    1. I’d take that definition further. Going from what my dear departed dad taught me at an early age:

      Ex = has-been
      Spurt = drip under pressure

      So an expert is a has-been drip under pressure. 🙂

      At work, in the IT/networking field, an expert is defined as “someone who doesn’t work here, who charges money to tell us things”. I think the theory is, if you have to pay for advice, it must be good.

      As far as sharpening things goes, I’m a self-confessed hack. I have a double-sided coarse/medium oilstone that gets me in the neighborhood, and a really old really fine oilstone that gets things sharp enough that I can cut myself really badly if I’m not paying attention (don’t ask how I discovered that one 🙂 ).

  11. Paul, I’ve learned tons from you so when you have a comment or observation, I accept it as gospel because thus far everything I’ve learned has worked and it has worked quite well and it has made things remarkably easy and logical.

      1. Now that’s what is known as a “Spot On” Dead Pan delivery, as you Old World Anglo’s are wont to say.

  12. Thanks for this interesting and useful posting.
    I was particularly struck by your comment that you should be able to spend only about 3 minutes in sharpening a plane iron – something which I have yet to achieve – and I wanted to ask if you clean off the surface of the diamond stones at every sharpening. We don’t see you do this on the videos, but this may be part of making these presentations in a given time.
    How often – if at all – should a diamond sharpening stone be cleaned off, and what is the best method?
    Thanks, as ever, for your on-going, practical assistance.

    1. I use 3 diamond stones and a strop for my routine. After sharpening I wipe of the stones with a shop towel that I keep handy, then brush off with a hand brush also kept handy. I’ve found the second operation seems to do a good job of removing little bits of grit and such that the towel can leave behind. Every now and then my stones do seem to get a bit slick from build up of some sort or another. When I start to notice this, I use denatured alcohol and one of those non-scratch scrubber to go over the stone. After that, I rinse the whole thing under the faucet and dry it off. So in normal day-to-day, my cleaning routine takes about 10 seconds and then infrequently, I spend an extra 5 minutes with the other process. For the record, I use water to keep things lubricated. I expect maintenance would be different if one used different types of stones or oil based lubricants. This works for me, but others may have luck with different processes.

  13. – People like the idea of precision. When my daughter received her primary school evaluation at the end of a school year, it was something like 93.54% as if it was meaningful to evaluate a kid learning achievement with such a precision.

    – Splendid furniture was made in centuries where the measuring system was different in each city. Precise measurement wasn’t available.
    Found on NIST (US) web site:
    “January 16, 1905
    Measures for the marketplace
    At the turn of the 20th century, uncertainty plagued U.S. markets. There were at least eight different gallons and four different feet in use, and inspectors were often poorly trained and working with outmoded equipment. NIST convened the first National Conference on Weights and Measures (NCWM) to write model laws, distribute uniform standards, and provide training for inspectors, which resulted in a more orderly and fair marketplace.”

    – Another good reason to sharpen frequently:
    Found on Narex web site:
    “Narex chisels are ground before being hardened, so you may find that edge retention improves significantly after the first couple of honings, this is completely normal and once the first couple of millimetres have been sharpened away you will begin to experience what a pleasure Cr-Mn steel is to use. ”
    – I haven’t seen significant benefit in sharpening at 1200 grit, I use a 325 then a 600 diamond plate and leather strop (with an abrasive product to clean vitroceram cooking plate). I only used the 1200 grit + strop for initial flattening of grossly 1″ from the edge.

    Sylvain

  14. Thanks Paul. As always, I appreciate you separating the practical hands on working advice from the theoretical that can make us over worry.

  15. Thanks Paul, I do use the Veritas sharpening jig on a diamond stone, it produces great results and only takes a couple of minutes. I do have some whetstones and I tend to use them when I want to polish them, however they are wet stones that don’t need to be kept in water. My tools are sharp and why spend hundreds of pounds on these sharpening systems, years ago it was oil stones. I love your videos and you have made me rethink about what I need in my shed. My table saw is going, my mitre saw is only used for construction projects and I do use a Track saw but only for sheet materials.

  16. I tried Pauls methods to the letter, and also the 16.000 grit stuff to the letter, for strictly recreational level work. Which am I still using? Pauls.

  17. Thanks Paul. I appreciate your common sense approach. A few years ago I received a Stanley #4 that was purchased at a local big box store. Using your “how to restore a plane” video I went through my plane and flattened/cleaned/trued the various parts that needed attention. It’s a usable tool now, and with the sharpening knowledge learned from you, I can now keep it sharp without too much trouble. I use a thick glass compounding plate with abrasive paper glued to it. It’s not the fastest as you say, but it didn’t cost that much either. Maybe someday I will invest in the 3 diamond plates. In the mean time I will continue to enjoy the making process.

    1. Cory, one thing I’ve noticed in my 78 years is, “If ‘Common’ sense were, there’d be more of it”. Mr. Sellers’ philosophy seems To be, “Do the best you can with what you have and strive to do better as you can”. When (and/or “If”) the cost vs. need of diamond sharpening plates become affordable for you and you believe they will improve the results you’re getting, by all means, acquire them. In the mean time, (as we say in the music world) “Practice”.

  18. The original “scary sharp” story began on a hand tool mailing list many years ago. It was named in jest (as in ‘he was shocked and awed at how sharp his plane was’— it was ‘scary’ that something so simple could be so effective, hence scary-sharp). It was meant as a joke name for a system that really worked, even for those individuals who had never (ever) before been able to get a truly sharp edge.
    Since that time, the term has morphed to mean many things to different people, but the original objective was to help people get a sharp edge: to learn what sharp meant, to experience it. It involves a very inexpensive way to learn on your own- a bit of glass, some pressure sensitive adhesive (PSA) backed “3-M microfinishing film” and two blocks of wood screwed together to hold the blade (dead simple as you say). If interested, do a web search for Brent Beach Sharpening Pages for some pictures and explanation. Brent has done a lot of research on sharpening and I guarantee you will learn something there.
    The abrasive used is a metallic oxide coated (some are diamond now) PSA backed Mylar film meant specifically for the metal working industry… it is a surprisingly long lasting abrasive film. One of the important bits of info: spritzing some soapy water on the glass and then floating the adhesive backed film into position allows you to stick it down evenly, flat, and in the desired location on the glass. Squeegee out the excess water and let it air dry overnight (air bubbles/creases/folds are otherwise a problem). The soapy water is used only to allow you to position the adhesive backed abrasive film on the glass evenly. It is not ”sandpaper”, it’s a thin sheet of firm plastic with a “peel and stick” adhesive on the back (much easier to use than the non-adhesive sheets they also offer). The total cost was less than $10 at that time, not including a couple of scraps of wood for the simple jig (probably more now?).
    This is also good for people who are not sure about woodworking (why buy expensive sharpening stones if you only want to check it out?). The system is teachable, repeatable, and easy. Best of all, it can be learned from the description alone, no prior experience necessary.
    Once you have truly experienced the joy of a really sharp blade, then you have a benchmark to know what you are looking for when you subsequently try an alternative method. It’s great for enthusiastic but frustrated people who just can’t quite get the free hand method to work for them yet.
    The OldToolsList still exists under Galoot Central if anyone is interested in joining (and there are alternatives also). Everyone is welcome who wants to talk or learn about old tools and how to use them (no politics or religion allowed).

    1. I was advised by a Japanese tool merchant in Seattle, about 25- 30 years ago, to use a jewelers loupe to check my edges when sharpening. It was a revelation, and continues to surprise me. A loupe is cheap and beats all other methods for checking your edge.

  19. Paul doth speak the truth here.

    I have gone thru all the methods mentioned here in Paul’s post and the comments. I mostly use diamond plates, but I also have some waterstones. Started out with sandpaper on granite years ago, and abandoned that very quickly. One of my waterstones is 12,000 grit, and it produces an edge that doesn’t require any stopping to get feather thin shavings.

    Just recently, I wanted to try something different with sharpening a chisel, as I remember years ago seeing a Japanese bladesmith sharpen a knife with a brick. Just a standard red brick, nothing special. He sharpened a knife with that brick and then proceeded to shave with it. His point was that all the fancy equipment in the world doesn’t replace skill.

    Anyway, I wanted to try something I previously thought was mostly impossible. So, using just a 220 grit waterstone, I sharpened one of my chisels. Then took it to a leather strop for cleaning up. Damned if it wasn’t able to shave hair off my arm after that. It was a revelation. The edge didn’t last as long as if I would have taken more time and used finer grit materials, but it was sharp enough for use. Now, I’m not going to give up the diamond plates and finer grit stones anytime soon, but it did show me what can be accomplished with some pretty simple stuff. Still kind of shaking my head on that.

    1. John, yeah! Years ago Don MacKenzie of Brewster, Cape Cod, more of a purist than most, showed how he sharpened his Sloyd knife on the grinding wheel. A few quick seconds on the ordinary grey wheel, then a few more on the adjacent buffing wheel with a fresh charge of rouge, and handfuls of hair came tumbling from his forearm, dry.

      My observation is that this is highly effective, but that I am certain that when using the grinding wheel I would remove more than twice as much metal than if I honed on a coarse stone, therfore my dear edged tools would have no more than half a useful lifetime compared to honing. L

  20. Being a site carpenter most of my working life we tended to hollow grind our planes and chisels almost to the edge, quite often the angle was much less than 25 deg, we didn’t need to be wasting time sharpening tools, time was money. I had nearly 8 years erecting hardwood conservatories, most evenings after work half an hour was spent sharpening planes and chisels ready for the next day, not every day but often. There were other chippies whose tools were blunt as the proverbial badgers backside, it amazes me that anyone ever employed them !

    1. Paul, glad you mentioned “almost to the edge”, that’s key to avoiding the heartache, misery, and self recriminations of a burnt edge! L

  21. Way off topic I guess. Been trying to get card scrapers “right” for years. Somewhere I saw a post about a jig. Cut a 2×4 to length & cut a slot with an inexpensive S&J saw. Low and behold a perfect card scraper. Anyone know where I saw this? 🙂

  22. Paul, an excellent point about “dead flat” reminded me of a video I watched a few years ago about a couple of Japanese Professors analyzing, in microscopic detail, the mechanism of how plane blades cut (yes I know I’m a Mechanical Engineering nerd) . I was awed by what I saw as the whole process actually eliminated the sole of the plane and they tested both with and without the cap iron. What seems to be the critical factor, more than anything else, is the shape and angle of attack of the leading edge of the chip breaker. Here’s the link to the video in all its translated glory.

    https://vimeo.com/158558759

    This will open many eyes to the numerous (mostly false) claims for flatness. It seems to me that the purpose of the sole of the plane is really only to establish the thickness of the cut–that is the amount the blade is set below the sole. Ergo the “flatness” is really a moot point.

    1. Michael, thanks for the link, I saw that too, enlightening. I think the sole flatness issue comes down to the shooting of edges for gluing, not surface quality (excepting that little bitty area at the mouth). I mean, you will never get a spring joint over a long edge if your plane has a hollow sole. L

  23. I’m a toolmaker by trade and have access to all the equipment I need to flatten plane soles within .01mm but I don’t bother. I had to do it once with a Record 41/2 that someone had attacked with a disc grinder and needed the surface grinder, angle plate etc to clean it up. Other than that one time, I’m happy once the areas around the mouth and the heel are in contact with the wood and that’s good enough. Obviously none of my planes are bent like bananas, but there’s no need for this business of trying to apply precision engineering standards to a woodworking tool.

  24. With older chisels bought on ebay the metal can be superb but to get them working properly it`s necessary to remove some rust pitting on the back face. Also a belt sander can give a quick flat surface and a quarter inch of a curve from previous abuse . Rather than wearing down the back it`s simpler to grind the bevel edge back to the straight edge with a hand cranked water stone. Remarkably quick to use and quiet as well . One or two old chisels had much deeper pitting so I reversed the bevel to the opposite side which was smooth and flat.
    So on ebay always check both sides of the blades before buying .

  25. In case we give Stanleys carte blanche to make their planes any old shape (as in the early RB10 planes ) it is quite useful to have a relatively flat sole to a plane. I bought the first version of an RB10 plane and it sat there unused for many years before a belt sander saved it .The later RB10 model was a big improvement but far from perfect (Heaven forbid ) but the technical mixing and blurring of each separate adjustment function was enough to confuse anyone . So plane soles –not perfect but straighter than a donkey`s hind leg would be favourite .

  26. I have a question. I realize the plane blade does not need to be flat because it is flexed into place when clamped into the plane. But, some work on the bottom to make the back near the edge smooth would seem to me give one a better edge when sharpening the blade. Is that true?

  27. Flattish.
    On a slightly related note I had to stop myself recently from going to town on the legs of an outdoor table. I had the plane, saw and squares all sitting ready to dial in those dimensions. Fortunately I went outside and ‘felt’ the patio underfoot – no place for precision.
    In my world I want things as flat as they need to be where they need to be – going beyond that often involves more work than benefit. Diminishing returns.
    Everyone needs to find they’re own ‘flat enough’. The joint fit, look, feel, purpose and tool use will usually tell you.
    Flatish.

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