Sunday, June 12, 2016

Two Stones And A Strop


A newly-made leather fold-up sharpening kit, setup and ready for use.

Two stones and a strop walk into a bar. The bartender says, "Oh great, do we really need another story about sharpening?"

But after watching the video below, he says, "Yes we do!" Because the punchline is that's all you need to get a tool razor sharp in seconds.


This video shows the method in action. For details, including how to make the sharpening kit, read on below.

So roll your eyes and bear with me! But this is a great method for beginner and experienced woodworker alike.

Credit To Charles Hayward

This method is based on reading the first chapter in the new compilation from Christopher Schwarz and the folks at Lost Art Press, The Woodworker: The Charles H. Hayward Years. This is a spectacular set, an invaluable resource.

Hayward was editor of The Woodworker magazine from 1939 to 1967. He covered a period when hand tool use was still widely practiced in the British trades. Many of the articles were written by working tradesmen with decades of experience. Hayward himself was superbly skilled.

These were people worth listening to. You can just picture these practical, no-nonsense craftsmen who needed to get a job done efficiently, no messing about, because time was money, and mistakes meant docked pay and rework. They did this stuff every day for a living.

That's no less true for today's professionals. Things are more relaxed for those of us who are hobbyists, but we can certainly benefit from their experience and methods.

Sharp tools were the key. The articles in Chapter 1 cover sharpening from several different authors. While there are some differences, there are a number of common points. They needed to get a good sharp tool quickly and get back to work, because sharpening time was overhead time. What struck me most was the simplicity in their process.

I've distilled that information and combined it with what I've learned from other sources, my own experience and learning curve, and what I've observed when teaching others how to sharpen. So while this my interpretation and presentation, it is consistent with the book.

This is going back to fundamentals. What's old is new again. Again.

Now, I know Chris also has a DVD called The Last Word On Sharpening, and it was his articles on sharpening in Popular Woodworking that first allowed me to achieve a sharp tool. But really, the last word won't happen until they pry the chisel from the last woodworker's cold, dead hands.

The Fundamentals

For bevel-down plane irons and bench chisels, the bevel angle at the cutting edge is 30 degrees. For paring chisels, the angle is 25 degrees. Other specialty irons and chisels may have other angles.

Sharpening consists of 3 steps:
  • Grinding
  • Honing
  • Polishing
Grinding

Grinding takes place on a coarse stone, at 5 degrees less than the cutting edge angle. This is known as the primary bevel. Because the bevel for the cutting edge is formed after the primary, it is known as the secondary bevel.

Grinding has one purpose: to remove metal to make honing easier. All other considerations are secondary. It doesn't matter how flat the primary bevel is, how rough or smooth it is, or how precisely angled it is. As long as it removes metal adequately, it's sufficient. At this coarse stage, speed is what counts.

It also doesn't go all the way to the edge. It goes close to the edge, about 1/32" away from it. By stopping short, you don't waste metal or effort unnecessarily.

Because grinding is on a fast-cutting coarse stone, it's fast and easy, even though the primary bevel is a large surface area.

Honing

Honing takes place on a fine stone, at the cutting edge angle, forming the secondary bevel.

Honing is where things get critical. This is where you produce the actual cutting edge. At this fine stage, precision is what counts.

Honing forms a burr, or wire edge, where the thinned metal flaps up. If you don't have a burr all across the edge of the tool, you need to continue honing until you do. The presence of a burr confirms that you've actually reached the edge. But as soon as you have a full-width burr, stop.

Because grinding has removed the bulk of the metal, leaving only a small surface area for the secondary bevel, honing is fast and easy, even though it's on a slower-cutting fine stone.

Polishing

Polishing takes place on a leather strop charged with compound, at the cutting edge angle, refining the secondary bevel and removing the burr. That last part is especially important, since even the finest stone will leave some burr behind.

This polishes the faces of the secondary bevel and the back of the tool. It wears off the burr and polishes out the microscopically jagged edge left behind where bevel and back meet. A polished surface meeting a polished surface intersects at a line to form what Ron Hock calls a zero-radius edge.

Burr removal can be accelerated by running the edge across the fibers of a piece of wood. You can also remove it by folding it back and forth with your thumb or across the palm of you hand carefully.

Back Preparation

This assumes that you've separately polished the back of the tool to remove all traces of machine marks. The back should be at a near-mirror polish before sharpening.

Don't obsess over slight low spots over the length of the tool, apparent as unpolished regions, just be sure the last half inch or so is flat and polished. Because the back is an enormous surface area, the amount of work required to get it absolutely flat with no low spots rapidly approaches diminishing returns and is not worthwhile.

The polishing step in sharpening refines the back at the edge and polishes off the burr remnants. Over the life of the tool, as it get shorter and your sharpening approaches any low spots in the back, you'll hone and polish them out bit by bit.

Repeat

When the tool is dull, repeat the entire 3-step process. By going through it all each time, the primary and secondary bevel are maintained in relative proportion, ensuring that each one is easy to restore.

Once you condition the tool initially to establish that profile, you'll always have existing primary and secondary bevels when you resharpen. Resharpening then establishes new primary and secondary bevels after removing just a thin layer of metal from each one.

An alternative approach is to only resharpen the secondary bevel, so that it grows over several resharpenings until you need to re-establish the primary bevel. The one drawback to this is that it makes the amount of honing required each time variable. Part of the simplicity here is in avoiding variability.

With this latter approach, the two bevels chase each other up and down the end of the tool over time, the demarcation line between them moving up until the primary bevel is almost gone, then down until the secondary bevel is almost gone.

Either way, just don't wait until the tool gets so dull that it needs a major resharpening job. It's tempting to keep using the tool as you remain focused on a task, but the work will go better if you take a quick sharpening break whenever needed.

Sometimes just a few licks on the strop are sufficient to tune up the edge.

Two Stones And A Strop

In these 3 steps, you can see the 3 abrasives needed: coarse stone, fine stone, and strop. While the book talks about oilstones, this method works with any modern abrasive: diamond plates, pre-soak waterstones, non-soak ceramic waterstones, sandpaper, etc.

The one major deviation I've taken from the book is in the use of a third stone before stropping. Several of the articles state that you can optionally hone further on an Arkansas stone if you have one, after removing the burr on a piece of wood.

I've opted not to include that third stone, because I found that it didn't improve the results I got from the other stones followed by the strop. That may be simply be a matter of my technique, so if you have one, it doesn't hurt to try it. See which option gives you the best results.

If a third stone doesn't offer noticeable improvement, it's an unnecessary complication. For me, the great value value in this system is spectacular results from breathtaking simplicity.

Is this the "best sharpening method"? I'll merely claim that it's simple, fast, and effective. I'll let others argue over how many angels can dance on a zero-radius edge. Meanwhile I'm getting back to woodworking.

The Process

I'll start using a simple shop-made portable sharpening kit. Portability is one of the other benefits of simplicity. I don't need to drag a lot of stuff around with me, and it stashes easily into a toolbox.

The kit consists of a leather fold-up case with wooden stone holders and a strop bonded to it, and a small Japanese toolbox matched to its size to hold the assorted items used in sharpening. I'll show how to make these in subsequent parts.


The leather case folded up, and matching Japanese toolbox.


The contents of the toolbox, for sharpening chisels, plane and spokeshave irons, scrapers, and saws. This photo is missing the 20 degree guide block and a sawset. I've shortened the bar clamp handle ends to make them fit more easily.

I use oilstones in the kit. I'll also show photos of other sharpening media. The process is exactly the same regardless: coarse stone, fine stone, and strop.

Mistakes

I show people how to use both convex bevel method and double-bevel method and let them choose whichever they prefer. I've been using a visual guide block for setting the tool to the right angle.

Convex bevel requires starting at this angle on the forward stroke, and returning to this angle on the backward stroke. Double-bevel requires maintaining this angle throughout the forward and backward strokes.

The primary mistake I've observed people make is judging angle, both at the start and on the return stroke. They may have difficulty aligning to the block initially, or difficulty knowing where to return to. The result can be an angle that's too high or too low by a good 5 degrees.

Too high an angle produces an obtuse edge that may be sharp but doesn't cut easily. Too low an angle means the sharpening doesn't actually reach the edge, it only sharpens somewhere behind the edge.

The other mistake I've observed is in the number of stokes. Too few strokes results in insufficient removal of metal. Too many strokes is unnecessarily wasted metal and effort, producing a large flap of burr that takes longer to remove and polish out.

To address the first issue, I've changed to a different type of guide block that gives you positive registration both at the start and the at the return.

In addition to 25 and 30 degree blocks for flat plane irons, I've made 23 and 28 degree blocks for chisels that are tapered in thickness. The 2-degree difference offsets the angle of the taper so that the back of the chisel is at 25 or 30 degrees relative to the sharpening stone. I also have a 19 degree block for grinding tapered paring chisels, which will be honed to 25 degrees.

The key thing about these is that while using them, you're training your hands to recognize specific angles. Eventually, like a violinist putting his hands on the strings at some specific point on the neck with nothing to guide him, you will be able to simply pick up the tool, put it on the stone, and set it to the right angle with nothing to guide you. This may take you 10, 20, or 50 sharpenings to achieve.

These two photos show how to use the guide blocks, here at the honing stage on a combination India stone. I hold the block with my thumb as I snug up the tool to the slope and just slide it down to contact the stone. The second photo especially shows what I mean when I say that the only purpose for grinding is to remove metal to leave a small surface for honing.


Aligning for honing.


Closeup: note the gap formed by the primary bevel, leaving just the edge touching the stone to hone the secondary bevel.

To address the second issue, I count strokes. This requires a calibration stage where you test your specific stones with your specific tools to determine how many strokes are necessary. I'll come back to that after I show how to sharpen.

Grinding

I'll start with a tapered chisel. I'm using Norton coarse and fine India stones in my leather case, and Flexcut Gold compound on my strop.

As you can see in the opening photo above, the case is clamped to the bench with a couple of small bar clamps. The heavy leather is stiff enough that this holds everything in place.

I set the 23 and 28 degree guide blocks at the near end of the coarse and fine stones and spread some mineral oil on the stones. The guide blocks make good oil spreaders.


Spreading oil on the coarse stone, using the guide block as a spatula.

I set the top face of the chisel flat on the 23 degree guide block bevel and slide it down until the existing primary bevel contacts the stone. Note that because of the existing secondary bevel, the very end of the chisel does not contact the stone.

This establishes the tool at the primary bevel angle.


Lay the chisel bevel down and flat on the guide block and slide it down to the stone.

I slide the tool forward and back while maintaing this angle. But remember that this is grinding, so the angle isn't critical. The key is that it's lower than the secondary bevel angle.

I count out 10 round-trip strokes. Why 10? I've calibrated this process on my stones and found that 10 reliably provides a sufficient grind. Maybe I could get by with 7 or 8, but I like to allow some margin for variability. This covers all my antique tools and my modern O-1 and A-2 tools; some just may be slightly more or less ground than others.

As with any sharpening method, make sure you walk the strokes sideways across the surface of the stone for even wear. Otherwise over time you'll wear a distinct low spot in the stone. The good news is that an unevenly-worn coarse stone will still produce an adequate grinding, it just may not do as pretty a job as a perfectly flat stone.


Maintain the angle reasonably forward and back throughout the stroke.

If you like, you can angle the guide block at 45 degrees across the stone and align the tool to that. If you're sharpening a plane iron that's wider than the stone, this allows you to keep the entire width in contact with the stone.


Alternative holding method: the guide block angled across the stone.


The strokes are the same, except that the tool is diagonal as it moves up and down the stone.

These strokes produce a new slightly convex primary bevel that comes to within 1/32" of the edge, shortening the existing secondary bevel. But only a thin layer of metal has been ground away.


While difficult to photograph, this shows the new primary bevel coming close to the edge. You can just see the remaining secondary bevel in the different reflection along the edge.

Honing

The honing process is virtually identical, using the 28 degree block on the fine stone. The only difference is that now the existing secondary bevel contacts the stone, which means the edge contacts the stone.


Lay the chisel bevel down and flat on the guide block and slide it down so the edge contacts the stone.

As before, I slide the tool forward and back while maintaing this angle. Here on the secondary bevel the angle is more critical. However, we know from the convex bevel method that as long as you don't raise it any higher when you draw back, you'll get the desired angle at the cutting edge.

You'll most likely end up with a very slightly convex secondary bevel. If you prefer to keep it flat, concentrate on holding your arms fixed as you rock your body forward and back. Tucking your elbows into your body helps keep your arms in place.

But as a practical matter, the secondary bevel is so small, and the convexity so slight, that there's no need to obsess over it.

Again, I count out 10 round-trip strokes. Why 10? Same story as before. This is sufficient to reliably produce a small burr with all my tools on these stones.

Also again, make sure to walk the strokes sideways for even wear on the stone. With this stone, that's much more critical than it was on the coarse stone, because this is the surface that shapes your cutting edge.


10 strokes on the edge while maintaining the angle.

Or you can use the alternate orientation of the guide block at 45 degrees across the stone.


Aligning the alternate hold with the block at 45 degrees across the stone.


10 strokes with the edge oriented diagonally across the stone.


This is the resulting new secondary bevel at the edge. It's hardly any bigger than before honing, because again just a thin layer of metal has been removed.

This should have produced a very small burr uniformly across the edge.

If you have a burr that is not uniform, you are probably rolling the tool sideways as you move. Experiment with different orientations, straight or at 45 degrees, or some other angle, or concentrate on avoiding rolling. Narrow chisels are the trickiest, because there's such a small registration surface.


On the back, that bright line at the edge is the burr flapped back and reflecting light differently from the rest of the back.


On the bevel, after flapping the burr forward with my finger, it's visible against a dark background as a bright line. That dark region is the secondary bevel.

To start the removal of the burr, I hold the back of the chisel down flat on the end of the stone and move it sideways back and forth or in circles for 5 strokes. Make sure to keep it flat. Don't lift the handle, or you'll create a back-bevel. While back-bevels can be useful on plane irons, you don't want one on a chisel.


Starting burr removal by moving the back of the chisel around flat on the stone for 5 strokes.

To further aid in removal, I draw the edge in a slicing motion across the fibers in a scrap of wood.

Polishing

I dress the strop liberally with compound. Then I hold the chisel at 30 degrees, the same angle the back had on the fine stone, and draw it down the strop, lifting it off to return to the far end. You can't push forward on the strop, because the edge will cut into it.

I use medium pressure. I don't want to dimple the leather and cause it to run over the edge at a higher angle.

I count out 5 strokes. Again, that's what works for me.


Draw the bevel down the strop for 5 strokes.

I draw the back of the chisel flat down the side of the strop for 5 strokes. Again, keep it absolutely flat to avoid creating a back-bevel.


Draw the back down the strop for 5 strokes.

This usually doesn't completely remove the burr. This is a little more variable because it depends on how big the bits of burr are, how much it was weakened by honing the back and drawing through the piece of wood, how much pressure you use, and the compound you put on the strop.

So after 5 strokes each side, I start taking alternating single strokes on each side, until as I turn the tool in the light, I don't see any more burr.

This produces a highly polished back and bevel.


You should be able to read text reflected in the back of the tool.


It's not perfectly mirrored, there are still tiny scratches visible.


The finished edge. As you turn it in the light, it should be highly reflective.

Testing

My favorite way of testing an edge is to take white pine end grain shavings with hand pressure. Because white pine is so soft, if the tool is not sharp, it will just crush and break the fibers. But if the tool is sharp, it will shear them off cleanly, producing a feathery shaving and leaving a smooth surface. You should also hear a satisfying schussing sound.

If the tool seems to cut well but there are scratches in the cut surface, there may be a bit of burr still left behind. Try a few more licks on the strop to see if that clears it up.

If not, and this is an old tool, there may be tiny cracks or pits in the metal. That might mean the tool is usable for general work where the cut won't be visible, but not for the most visible spots.


Slicing cleanly across the end grain, producing a feathery thin shaving.


The clean surface left behind after taking two shavings.

That's the real acid test. But a further test I like to do is pare off some chips more along the grain, then examine the surface left behind.

When a tool is sharp, I can only describe it as buttery going through the wood. The cut surface is gloriously glassy smooth.


Taking long grain chips, like a hot knife through butter.


The cut surface, with precisely-defined edges. No tearing of edges or surface.


Repeatedly slicing through the wood is joyous, creating beautiful curls and sharp facets.

Of course pine is easy. But you should find the chisel just as effective in hard woods, leaving cleanly sheared surfaces and edges. You just may need to use a mallet instead of hand pressure.

Review

Take a moment here to note how simple and fast this is:
  • 10 strokes grinding.
  • 10 strokes honing.
  • 5 strokes polishing the bevel.
  • 5 strokes polishing the back.
  • Another 4-10 strokes total polishing.
That's fast. And it's highly effective.

Conditioning

When I first sharpen a tool with this method, I have to condition it to this bevel profile. Whether it has a factory profile, a profile some previous owner put on it, or one I put on it with some different method, I need to spend some time preparing it.

This is often more than I want to do on my coarse stone. First, there is enough metal to remove that it would be a lot of work on that stone, and second, doing all that work puts more wear on the stone than I like.

For the heavy shaping required by conditioning, I use a DMT extra-extra coarse diamond plate, held in the divider/auxiliary holder from my kit. Lubricated with water or window cleaner, this thing eats metal.

I setup the tool with the 23 or 25 degree grinding guide block and work the primary bevel 10-20 strokes at a time, just like on the coarse stone. I check it after each batch of strokes to make sure I'm shaping it as desired and see how close this new primary bevel is getting to the edge. I want it to get within about 1/32".


Conditioning a plane iron to this method on the XX-coarse diamond plate.

For a tool is seriously out of shape, I follow up with a few strokes with the 23 or 25 degree honing guide block to work the secondary bevel. On this small surface area, it goes really fast, so be careful about taking too many strokes. If you overdo it, do a couple more strokes on the primary bevel.

This establishes the bevel profile and relative proportions of primary and secondary bevel that the tool with have moving forward. If you prefer a longer secondary bevel than I use, do a few more strokes on the secondary bevel. Then during calibration you'll determine how many strokes are necessary on the fine stone to hone that larger secondary bevel.

Once I've done the heavy grinding on the diamond plate, I go back to the regular method. The coarse stone cleans up the heavy scratches left by the plate and takes the primary bevel down just a hair. The fine stone does the same for the secondary bevel.

With a few tools, I've found it useful to immediately go through an additional coarse and fine sharpening cycle. That extra sharpening gets the shape exactly where I want it.

Then I finish up with the strop and the tool is conditioned to the method and ready for use.

Calibration

When I try out a different set of stones, I need to determine how many strokes each one needs. While 10 strokes has worked out as a good general purpose number, some stones are definitely different from others.

One major difference is when using waterstones. Because I want to avoid scoring or gouging the surface of the stone, I only apply pressure on the back stroke. On the forward stroke, I ease up and just glide over the surface. So the abrasive action is only happening on the trailing half of the round-trip. That means only half the strokes are doing anything, possibly requiring more strokes.

I calibrate 5 strokes at a time. I setup the appropriate guide block for the stone and take 5 strokes. Then I examine the results. If it needs more I do another 5. I repeat if necessary. In general I prefer to overshoot just a bit. That ensures I'm getting a full sharpening. A couple of extra strokes won't hurt anything.

For the coarse stone, I have enough when I see the primarily bevel is within 1/32" of the edge.

For the fine stone, I have enough when I feel a small uniform burr as I run my finger forward along the back and over the edge.

I keep things simple by using the same number of strokes for different stones and different metals. The result is that the exact profile is a little different depending on which stones I used, due to the relative cutting speeds of the different abrasive types on different modern and old steels.

Typically, though, you'll probably just use one set of stones, so it's just a matter of calibrating your particular set of stones and tools.

Plane Irons

Plane irons are exactly the same process. The only additional considerations are that now you're dealing with a much wider surface area for the primary and secondary bevels, you may want to feather the sides of the edge, and you may have a skewed or cambered iron.

For plane irons that are flat, not tapered, I use the 25 and 30 degree guide blocks. Some irons for wooden planes are tapered, so I use the 23 and 28 degree blocks. Specialty plane irons such as low-angle bevel-up planes may call for other angles.

You may find that the wider iron surface calls for a couple of additional strokes because there's more overall friction. Regardless, make sure you're applying even pressure all across the edge, which may require spreading your fingers across it.


Setup on the coarse stone at the 25 degree grinding angle and take 10 strokes.


Setup on the fine stone at the 30 degree honing angle and take 10 strokes.

If you want to feather the sides, this is when to do it. Tip one corner just off the stone and apply pressure down on the other corner. Take 10 strokes. Repeat on the opposite corner.


Feathering the edge on the left, with right corner tipped off the stone and finger pressure on the left corner.

Next lay the end of the back flat on the stone and take 5 circular strokes to work the burr a bit, then run the edge through a scrap of hardwood to weaken it further.


Running the edge through the corner of a scrap of cherry.

Dress the strop with compound and strop the secondary bevel and back.


Drawing the secondary bevel down the strop for 5 strokes at 30 degrees.


Drawing the back flat down the strop for 5 strokes.

Repeat alternating strop strokes as necessary to remove the last vestiges of burr. Remember that any little bit left behind will leave scratches in the planed surface.


The end-grain shaving test, producing beautiful feathery shavings and leaving a cleanly-sheared surface.


The long-grain shaving test, taking beautiful curls and leaving a glassy surface.


Planing end grain, producing long continuous pencil-sharpener shavings and leaving a clean surface.

Skewed Irons

There's really nothing special about doing skewed irons. You just hold the iron skewed as you align it to the guide block. Then you maintain that skew as you do your strokes.

This may be a bit more awkward to hold and maintain, but shouldn't be difficult.

Cambered Irons

A cambered iron is similar to a feathered edge, except you need to apply the camber at the grinding stage as well as the honing stage.

I do the edge in linear segments, flat across the center, than working to each side in two segments, then just a little across the points where the segments meet. This produces an approximation of the true curve of the camber, and is sufficient for irons used for rough work, such as as scrub and jack planes.

If I want to smooth out this approximation, I hold the iron at the proper angle, then rotate it sideways left and right from my wrist, tipping the edge as I move through the stroke to make the sure the entire curve goes through contact with the stone.

Other Types Of Stones

This method works with any kind of stone, and should work with any kind of abrasive surface, such as sandpaper or abrasive films. Whatever you use, you just need coarse and fine grits.

I've used it succesfully with DMT Duo-Sharp diamond plates, Ohishi non-soak ceramic waterstones, and Norton pre-soak waterstones.

You can even use a single combination coarse/fine stone as a low-cost alternative. I've used a humble Norton IB8 combination India stone; it wasn't even a full stone, just a shortened one where a 2" chunk had been broken off, equivalent to an IB6.


Using DMT Duo-Sharp diamond plates, Black and Green color codes.


Using Ohishi waterstones, 1,000 and 10,000 grits. There's a DMT Dia-Flat lapping plate at the far end for flattening them. Looks like I need to cut this holder down to eliminate the extra space! Also, you can see I used to use a green chromium oxide stick on my strop.


Using Norton waterstones, 1,000 and 8,000 grits. There's a DMT Dia-Sharp coarse plate for flattening them.


Using a 6" chunk of Norton IB8 combination India stone.

I found the Ohishi stones produced the finest edge right off the stone, but the strop was the great equalizer. It may offer the least benefit for those stones, but it brought all the other stones up on par with them, so any of them work equally well with this method.

Just remember that regardless of how good a job the fine stone does, the strop is still necessary to remove the last remnants of burr and polish out the microscopically jagged edge it leaves behind.

When choosing which type of stones to use, it's a matter of deciding which mess and other considerations (such as flattening stones) you want to deal with.

Spokeshave Irons

Spokeshaves and other specialty tools have short irons of varying widths. These can be difficult to hold, and even harder to align to the angle blocks.

For these I've made up an auxiliary holder that acts as an extension handle. This makes these stubby blades much easier to manage.


Setting up for honing with a spokeshave iron in the auxiliary holder.


Closeup of the alignment and primary bevel gap.


Top view of the holder, with a knob-attached screw for tightening.


Bottom view, with a square nut let in so it can sit flat against the angle block. A longer screw in the handle would've been nice!

Continue to part 2 to see how to make the angled guide blocks.

24 comments:

  1. Steve!

    Amazing! Hands down best write up I've ever read on sharpening!

    ReplyDelete
    Replies
    1. Thank you so much Freddy, that is very kind!

      Delete
  2. I echo Freddie's comments. Truly a labor of love! Thank you so much.

    ReplyDelete
  3. Steve, great report. When you use a 8000 or 10000 grit stone do you still benefit from the strop?
    Thanks again, Joel

    ReplyDelete
    Replies
    1. Thanks! Yes, because these fine stones will leave a burr. The strop polishes out any burr remnants, as well as the microscopically jagged edge it leaves behind.

      Delete
  4. This is fantastic! I hollow grind... At times without a secondary. The comment on the growing honing area resulting in varying times to hone is spot on. I need to experiment with this.

    ReplyDelete
    Replies
    1. I built two blocks 23 & 28 and processed four chisels. Had been hollow ground so they needed a bit of conditioning. On about the 4th chisel I could feel where and how my fore arms were landing on my body (muscle memory). The periodic confirmation with block was a great confirmation. I used my well worn DMT diamond plate, medium India, surgical black oilstone, and a strop. The process exceeded my expectation and definately is my go to. Looking forward to part 3. Thank you for the great series!

      Delete
  5. Holy cow, that was a great write-up and video. I know and can appreciate how much work went into it, so thank you very much for that. I've been reading the Hayward books and have read the section on sharpening, but I must've missed the article on the angled blocks. I'll have to get back to that. Thanks again.

    ReplyDelete
    Replies
    1. Thanks! The angled blocks are my addition to the process, because I saw that many people had trouble identifying the angle and maintaining it.

      The Hayward articles would say "Grind at 25 degrees", but without something to guide them, people would hold their tool at anywhere from 20 to 30 degrees as they started and moved through the stroke, thinking they were at 25 degrees. A degree off one way or the other isn't a problem, but this much variation is.

      Then the next time they tried it, they might hold it at some angle up to 5 degrees different, still thinking it was the same angle. That lack of consistency was the real issue. In order to make sure they actually got a burr, they would end up using a higher and higher angle, so that eventually the edge would be as much as 35 degrees.

      The blocks are intended to teach the hand control necessary to use an appropriate angle to start with, and then maintain that angle with a reasonable degree of consistency throughout the process. After enough practice, you can eliminate the blocks and just do it freehand and know you're hitting the right angle, the way the old-timers in Hayward's articles did.

      Delete
  6. Good writing and great examples.
    Thanks!

    ReplyDelete
  7. Great write up! So I've seen this before that India Coarse >India Fine >Strop does the job, but then I found it just too hard to believe! Can I just ask for confirmation that you've had good experience with this combo so I can greatly simplify my life, ease my wallet and be forever in your debt?

    ReplyDelete
    Replies
    1. Thanks! I understand your skepticism, I also felt it for a long time. But the repeated consistency of the Hayward articles convinced me to try it. And yes, I can confirm that it works, repeatedly over and over. The photos and the video show it.

      I think the two keys are first to get control of the angles using the guide blocks, and second to adequately condition each tool to the method and the bevel profile. That conditioning may take a little extra work, but once done, it's proving extremely easy to maintain.

      Delete
  8. Steve, please clarify something for me. I have a few new Sweetheart chisels that are still in the box, and I am planning on sharpening them for the first time. I was going to use glass and sandpaper, but instead of spending money on that, I am going to get myself some India stones, a strop, and an extra extra course diamond stone. All of this looks to be under $100, and should last me forever.

    Anyway, my question is around the conditioning part of your article. You say "I setup the tool with the 28 or 30 degree grinding guide block and work the primary bevel 10-20 strokes at a time, just like on the coarse stone." Do I read the degrees correctly? I thought that the primary bevel was 23 degrees for chisels, not the 28 degree secondary bevel. Don't I want to remove the most metal on the diamond stone at the lower degree angle (23 degrees), which sets my primary bevel?

    That's my only question, which considering I have never sharpened anything other than hooks for saltwater fly fishing means that your article is completely understandable for an amateur like me.

    Thanks.
    Joe

    ReplyDelete
    Replies
    1. Good eye! You are correct, I had the wrong angles listed for conditioning. They should be 23 or 25 degrees, not 28 or 30 degrees. I've corrected the post.

      The new chisels may need very little conditioning if they have a 25 degree factory grind on them already. So the conditioning step may be pretty easy, just a matter of getting them tuned consistently to your guide blocks.

      Where conditioning tends to be a lot more work is in old tools where the previous owner may have used a bevel profile that differs significantly from this one, or just wasn't very consistent.

      Delete
  9. Thank you Steve!
    I also saw your course Intro To Hand Tools and I'm curious.
    For daily work at the workbench, what method you prefer and what type of stones?

    ReplyDelete
    Replies
    1. This has become my regular method. I use the leather rollup kit with the Norton India stones for everything, in the shop and for travel.

      It really is a simplification over what I showed in the course, which was the way I did things previously (primarily with the India Stones in a portable sharpening station).

      I do still randomly use my other stones just to keep in practice with them, but using this method.

      So what I showed in the course works, but this cuts out of some of the complexity and is still just as effective, showing the evolution of my sharpening methods.

      Delete
    2. There is something mystic abut sharpening, there is a need to test and experiment, always have the feeling that you can get a better result. No matter how much I read when I had the opportunity to buy 10000 grit waterstone I did, I had to check...

      Delete
  10. Steve - Great video and I'm really impressed with how simple and effective this method is! In the video you showed using india, water, diamond, etc. Do you find any noticeable difference in the type of abrasive you've tried? Also, the Norton india stones, are they the 8" x 3" size? Did you make your strop with a piece of leather glued on to a piece of wood?

    ReplyDelete
    Replies
    1. One other question for you ... do you do anything to flatten india stones like is required to do with water stones?

      Delete
    2. Thanks, Paul! I didn't find any major differences between the different abrasives except perhaps the Ohishi waterstones, which left the best polish. However, the strop is the equalizer, leaving them all equally polished.

      The Norton India stones are the 8"x3"x1/2". Check part 3 of this series to see how to make the strop.

      India stones don't need flattening like water stones. Water stones are softer and break down to form a slurry that performs that actual cutting action. Flattening water stones is therefore a regular maintenance operation every time you sharpen a tool.

      India stones don't work that way. The oil is a lubricant to float the metal swarf off the stone. The stones themselves wear very slowly.

      India stones can be worn to an uneven surface if you don't spread the wear over the whole stone. If that happens, you can restore them to flat on a diamond plate like the DMT Dia-Flat. But that's rarely needed.

      Delete
  11. Fantastic post, I return to it all the time!

    Any thoughts on grit size using this metod? In the post you use different abrasives and the end result is the same, the strop is the equaliser. But If the main goal is fast back to work, I imagine using a stone as coarse as possible before stroping could shorten the amount of time spent sharpening. If that is the case, I wonder which grit size steps you think would be optimal for grinding and honing?

    ReplyDelete
    Replies
    1. Thanks! Whatever type of stones you use, use the "coarse" and the "fine" grits. So for waterstones, 1,000 for coarse, and 8,000 or 10,000 for fine. The India stones I used aren't labeled numerically, they're just called coarse and fine.

      The key to speed on the first stone is definitely using a very coarse grit, to remove that metal quickly. So it doesn't hurt to use something even coarser than I did here. You don't care how rough it leaves that surface.

      However, the key to speed on the second stone is not coarseness. It's the fact that there's only a small metal surface to hone. It's just a a strip at the cutting edge 1/32" to 1/16" deep. So even extra-fine stones can hone it quickly.

      You don't want to use a coarse stone for the second stone because that would leave lots of heavy scratches on the cutting edge, that you would then have to add another step to hone out.

      So use a coarse stone on the first step where there's a large surface area to remove and the focus is removing lots of metal fast, and a fine stone on the second step where there's a small surface area to remove and the focus is getting a fine, clean edge.

      Delete