Flattening chisel backs with waterstones

[Dan McGonigle]

Hey guys, ive decided I need to get more serious about my sharpening. The 10 or 12 chisels and 7 or 8 hand planes I use were all sharpened and set up before I really knew much about sharpening. Until now I've been using 1000 and 6000 grit Japanese style waterstones, keeping the 1000 flat with sandpaper on granite and flattening the 6000 with the 1000. Recently I bought an 8000 stone and a leather strop and 1 micron compound. I'm going back through all my edge tools and re-flattening, setting new bevels and re-honing. I've started by flattening chisel backs on a 220 stone, keeping the stone flat with loose silicone carbide on granite. Working on the 220 stone I'm getting immediate results. Marking the back with a sharpie, only after a few strokes the marks are gone and I get a uniform scratch pattern. Moving on to the 1000, things are going slow. I'm not getting a uniform scratch pattern after a few minutes of working back and forth and it appears I have a low spot or two that the 1000 isn't touching. I'm taking care to not dish the stone and re-flattening it frequently. Am I making a mistake going from 220 - 1000? Or should I lower my time expectations and keep working on the 1000 until I get the sheen I want to move on? The chisels are Narex brand, not super high quality but I've heard should get flat prettt quick.

[David Eisenhauer]

I would add in a step or two between 220 and 1,000. if nothing else, it will speed things up quite a bit. If I have a chisel back or plane iron that is really, really bad out of flat, I use 80#, 120#, 180#, 220 grit (or close to those grits) sand papers on glass, then go to both sides of a 300#/600# diamond plate, followed by an 800# King waterstone. After that, I go to my three daily use Sigma waterstones - 1,000#, 6,000 and 13,000#. If the chisel or plane iron is not as bad as that, I may start with the diamond plate, go to the 800# and then my three daily use stones. Basically, I pick a grit and try it out briefly for a quick assessment. If it looks to be not removing much of the hump or belly, then I drop down a few grits until I get to one that it appears to be doing some immediate good. I have found that it is quicker overall to start rough and work up rather than work, work, work with lighter grits.

[steven c newman]

I flatten on the side of the grinders wheel. simple, quick. then it can go through the other steps like the bevel.

[William Fretwell]

I've gone through this with a large Narex set. Many years later my son still comments "remember those chisels you flattened" with a big grin on his face. I wish he could remember a few other things!

So yes it's slow, use a series of stones and diamond plates if you have them. I flattened almost the whole back but recommend you don't!

Worth it? Having bought them what choice do you have? They are decent chisels but not my best.

[Robert Hazelwood]

What kind of stone is the 220? If its a waterstone then you need to be vigilant about flattening- course waterstones especially will go out of flat very quickly. Likely you'd need to re-flatten the stone many times during the course of flattening a chisel back, if you want to keep it really dead on. That's kind of a hassle, and is why I don't care for coarse waterstones for back flattening.

Anyways, if the 220 is going a bit out of flat as you're working with it, then that explains why you have low areas that the 1000 grit stone won't touch. The other thing is that the slurry/mud from a coarse stone seems to be able to put a scratch pattern on low areas, making it difficult to identify those low spots until you move to a finer stone. If you're going to use waterstones for this then it would be nice to have a stone between the 220 and 1000.

Personally I think it's hard to beat sandpaper for this job. 80 grit PSA on a decently large flat surface makes quick and accurate work- faster than any other method I've used, by far. Then you can use an intermediate grit before going to the 1000 grit waterstone.

[Hasin Haroon]

Dan, it sounds like your chisels were fettled (to a lower degree) before you bought your new stone and strop. If you are just enhancing the sharpness of your tools, likely the backs of the chisels aren't too far out of flat to begin with, so I would just skip the #220 and start at around #600. If your chisels are pretty decently flat you could just go to the #1000 directly to see how it fares. As others have mentioned, the jump between #220 and #1000 is pretty large, and #220 is a pretty coarse grit to use on a tool unless you need to reshape the edge.

[Robert Engel]

Scratches have to be removed incrementally 220 -> 1000 is to big a jump.

Go to 400, then 800 (or straight to 800), then 1000, then 4000, then 8000 then the strop and you'll have a nice mirror finish.

[Patrick Chase]

I've gone through this with a large Narex set. Many years later my son still comments "remember those chisels you flattened" with a big grin on his face. I wish he could remember a few other things!

I think I've said this in a couple other places, but the reason Narex chisels are inexpensive is because they use a hardening process (austempering) that produces relatively little distortion, and they therefore do all of their machining in the unhardened state. Post-HT machining is expensive.

The problem is that "relatively little distortion" is not "no distortion". Every set of Narex chisels that's ever passed through my hands has had at least one bellied chisel, and those can be an epic pain to fix. Platter grinders with diamond disks are the fastest option I've found, FWIW.

To the OP: If you can access it then you might want to check out David Charlesworth's FWW article on the topic. The technique that he describes does a good job of maximizing the amount of tool flattening that you can accomplish between waterstone flattenings.

[Jim Koepke]

My experience with waterstones below 1000 led me to using sandpaper on tile or granite for the coarser grits. From 360 sandpaper to a 1000 grit water stone isn't a big jump.

The metal piles up on the sandpaper and needs to be removed often. A brush, vacuum or a strong magnet wrapped in paper does the trick.

jtk

[David Ragan]

I'm in the 'dont' skip grits camp.

Be not discouraged. It is surprising how fast and easy it is to work through the grits once you have a system.

When occasionally confronted w (given the opportunity?) the situation of having to remove a lot of metal, I tired of grinding the dickens out of my water stones, w all the truing/flattening of them during the process.

More metal needed to go, easier. I had no idea how to proceed, just needed something coarser, that did not need flattening (at the time was oblivious to diamond paste).

So, I printed some charts:

DSCN0867.JPGGLGC.png016.JPG

Recall that you want a larger particle size (more coarse) for more removal of metal (we are at the very edge of my brain on this, so the engineers can go into the different alloys and appropriate abrasives.)

My coarsest DMT diamond is about 60um, and was too much work. So, from the above charts, I got out my Klingspor catalog, and started w FEPA (European grading system) 80-which is about a 200um size particle.

The picture below is what I wound up with-SiC self adhesive rolls. (I only use this system for times when a lot needs to be removed.)

Plate glass, 3/8"" thick for the 8 grades mounted on a flat shelf...the great jig on it's side behind the board is from VSC tools (somehow, I ground down my LV jig's brass roller on these super coarse surfaces, that's not supposed to happen, right?)

002.JPG

The diagonal plate on top w 3 grades of abrasive is strictly for your issue-flattening backs; requires a different approach-no jig needed. (The glass there is just cut off scrap my Hardware store guy gives me.)

Sandpaper has it's detractors, However, sometimes I would rather just flatten/bevel/straighten, etc whatever it is in the shortest period of time, cost becomes less of a factor.

If the above plate glass is not flat enough given modern tolerances, I have not been able to tell it when switching over to the waterstones @ end of process.

Jim is correct about the swarf-it does accumulate rapidly (I have not tried magnets-great idea Jim)

[Mark Stutz]

I gave up on waterstones for flattening chisels or plane irons very quickly. I almost obliterated the 220 half of a Norton stone in a very short time.

[Patrick Chase]

I gave up on waterstones for flattening chisels or plane irons very quickly. I almost obliterated the 220 half of a Norton stone in a very short time.

Yeah, that is one extremely soft stone, and not worth the hassle IMO.

In other posts I've argued the "layer model of waterstone life", i.e. the stones contain a certain number of usable layers of abrasive, and you can roughly compare them to other media on that basis. 220# is about 60 um, so the 25 mm thick, $30 Norton 220 contains about 400 layers of abrasive (maybe a bit more because of the way the grains pack in, maybe a bit less because of the volume taken up by binder).

You're therefore paying about $0.08 per 3" x 8" layer of abrasive, or $0.30 per 9 x 11 sheet equivalent, which is not all that much cheaper than comparable quality Al-Oxide sandpaper. What this serves to demonstrate is that waterstones cease to have compelling economics at such coarse grits, and are therefore not worth the hassle.

[Rob Luter]

I use diamond plates for the coarser work, followed by 3M abrasive films stuck to thick glass mounted on MDF blocks. It's worked well for the last 10 years or so. I can get a mirror polish without a whole bunch of effort. In the grand scheme of things, it was a cheap solution too.

[Patrick Chase]

I use diamond plates for the coarser work, followed by 3M abrasive films stuck to thick glass mounted on MDF blocks. It's worked well for the last 10 years or so. I can get a mirror polish without a whole bunch of effort. In the grand scheme of things, it was a cheap solution too.

That looks simple but effective. Nice!

You appear to be using 1 um (green) and 0.3 um (white) 3M 261X film. Are you using an extra-extra-fine DMT plate (3 um abrasive) or something like that before the films? How long do the films last for you?

I use that stuff stuck to sticks a fair amount for tools with curved edges.

[David Ragan]

In other posts I've argued the "layer model of waterstone life", i.e. the stones contain a certain number of usable layers of abrasive, and you can roughly compare them to other media on that basis. 220# is about 60 um, so the 25 mm thick, $30 Norton 220 contains about 400 layers of abrasive (maybe a bit more because of the way the grains pack in, maybe a bit less because of the volume taken up by binder).

You're therefore paying about $0.08 per 3" x 8" layer of abrasive, or $0.30 per 9 x 11 sheet equivalent, which is not all that much cheaper than comparable quality Al-Oxide sandpaper. What this serves to demonstrate is that waterstones cease to have compelling economics at such coarse grits, and are therefore not worth the hassle.

Great analysis Patrick....the premise here is that one flattens often, and just until the pencil marks are gone?

I just had the feeling that for hogging off a lot of metal, sandpaper on stable substrate is the way to go.

Has anyone ever done an empirical test to see if your calculations translate into real world comparable results? Anybody have a diligent teenager that we could take up a collection and do a trial?