how coarse a stone do I really need?

[dan sherman]

I have seen people recommend everything from 220 grit to 1000 grit, for flattening the back of a plane/chisel, or re-establishing the bevel.


So how low do you go, and why? :D

[Augusto Orosco]

I have seen people recommend everything from 220 grit to 1000 grit, for flattening the back of a plane/chisel, or re-establishing the bevel.


So how low do you go, and why? :D


I guess it really depends on what you are trying to flatten. I once made the mistake of trying to 'flatten' the back of the blade that came with my new Lee-Valley BU Jack with a 220 grit water stone. The back ended up looking less polished than when I started (and yes, I was also re-flattening the 220 stone frequently... those suckers get out of flat pretty quickly). I took me a while to get it back to where it was with my 1000 stone. Only when I got to the 4000-8000 grit I noticed some improvement. Newbie mistake :(

I am sure the case would have been different had I been working with a rusted old blade from a flea market.

[Sean Hughto]

If you need to restore a nicked or chipped blade ( or worse yet, a broken one - never pry with a chisel, for instance ;-)) and don't own a grinder, a 220 stone is nice to have as the thousand will take for-freakin-ever.

[Mark Roderick]

If you're trying to flatten the back of something or re-create a bevel, don't use a waterstone. You'll go crazy trying to keep the stone flat. Instead, glue some sandpaper to a sheet of glass and have to it. Yes, the sandpaper can get "dull" after a while, but that's easy to fix. The key is that it will stay flat forever.

[Doug Shepard]

It all depends on how nasty it is. I've gone as low as 60 grit paper on some real ugly stuff. I always attempt to flatten or redo the bevel with the finest grit I can that will get the job done. But if you check after a minute or so and you're only making contact in a couple of spots, it's going to be a long slow job unless you start getting more agressive. 180 grit sanding screen works pretty well on some of the nastier jobs as it cuts a little faster than sandpaper.

[Wilbur Pan]

I like using waterstones. I really really really really like using waterstones.

But if I need to do some major work, like reestablishing the bevel, or grinding out a nick, I'll use Norton 3X 80 grit attached with some spray adhesive on a granite plate. Not so much for the coarseness of the grit, but for the flatness of the surface. I have yet to find a <1000 grit waterstone that will stay flat for very long.

[dan sherman]

so it sounds like for rough work, it's scary sharp or grinder, because solid diamonds stones aren't flat enough?

[Wilbur Pan]

People have reported issues with the flatness of diamond stones. For me, it's that they start cutting aggressively when new, but after a short while the cutting speed slows down quite a bit.

One other option for rough grinding is to use a cast iron plate with carborundum powder, which is pretty fast, but that's not a real popular option.

[Sean Hughto]

I wouldn't agree with that. These, for example, would work fine:

http://www.woodcraft.com/Images/products/146024.jpg?rand=303123600

[Mark Roderick]

You got it exactly right.

[Jim Koepke]

My vote is for using sand paper on a flat surface. At this grit, the stone will be more costly than the paper.

My choice is Pressure Sensitive Adhesive backed paper on a 4-1/2 inch wide roll.

Supergrit.com has been a good source for me.

jim

[Mike Brady]

Sean, you show a photo of two new DMT stones. I have those stones as well as the DMT Dia-Sharp continuous stone in X-Coarse grit. Technically, you are correct that any of those stones in the coarser grits will easily, when new, establish a new primary bevel on a plane blade. After one or two honings of, say, a Lie-Nielsen low-angle jack plane iron, you might come to a different conclusion. The cutting ability of diamond stones degrades very rapidly. I would estimate that to put a new bevel on on the above blade (not a micro bevel) would take at an hour of constant lapping on a extra coarse diamond stone that is not brand new. Granted, from that point, it is then easy to put a tiny microbevel on and get back to work. I would agree with the other poster that 80 grit 3X Norton paper is much more up to the task.

[Sean Hughto]

Here's my experience: If I need to change a bevel or remove any serious amounts of metal, I use my grinder(s) (yeah, I have more than one because I was still learning the "buy the best once" lesson), so, no, I'm not routinely using my Duosharp to take 10 degrees of steel off a 2" wide blade. I do have a coarse/extra coarse Duo sharp, however, and use it routinely to start to flatten backs and when rehabbing vintage chisels and the like. This is my second one, because after about 3 years of use, my first had indeed lost some aggressiveness. In short, the Duosharp:

- would not be my first choice to remove serious amounts of steel
- it would however work and be a lot faster than a 1000 grit stone/plate as suggested in the original post
- does wear out like most other abrasives of any sort
- but does not wear out at anywhere near the rate you suggest

YMMV

[george wilson]

Sean,our millwork shop used your same stones,and they were not particularly flat. I had to choose a steel backed diamond stone from several to find a flat one. It's a little tricky to tell which stones are the flattest,because the steel rule sits on top of the diamonds,showing light under the straight edge all across the stone.

[Sean Hughto]

I tend to use Norton Water stones for most chisel and plane iron sharpening (1000, 4000, 8000) - and regularly flatten those. I have only the coarse/extra coarse Duo sharp for prelimianry shaping and back flattening. I've never even checked its flatness in any way, though unless it was grossly out of flat, I think it would still do okay on the coarse work I ask of it to get the steel ready for the finer stones. I've never used the DMT metal plate stones. I assumed I wouldn't like the fact that their abrassive can't be refreshed by flattening/ exposing the next layer of bound grit as with oil and waterstones. Good to know that they aren't flat either!

[Wilbur Pan]

I have only the coarse/extra coarse Duo sharp for prelimianry shaping and back flattening. I've never even checked its flatness in any way, though unless it was grossly out of flat, I think it would still do okay on the coarse work I ask of it to get the steel ready for the finer stones.

If anything, I've found that having a flat reference on the coarser grits is more important than having a flat reference on the finer grits. Using coarser sharpening media of any type is going to remove more metal, and if it's not flat, that will leave a non-flat surface on your tool.

If I try to correct the non-flatness at the next sharpening step, by moving to a finer sharpening medium I'm slowing down my metal removal rate, which means that it takes longer to correct the non-flatness than it did to cause the non-flatness in the first place.

By making sure that you have a flat reference at the first steps of sharpening, you'll speed up the sharpening process overall by a lot. I've found that ideally, the majority of sharpening happens on the lowest grit that I'm using, and the following honing stages go by pretty quickly.

[Sean Hughto]

Well, that makes sense, but I think we'd need to specify exactly how a sharpening surface is out of flat (what shape is it?) and what operation you are trying to do on the surface (flattening the back of a 2" blade, for example, is rather differnt thatn establishing a bevel on a 1/8th inch one, etc.). Anyway, I've never checked my Duosharp with a straight edge and feeler gauge, and I've never had any issues where the 1000 grit took forever because it was correcting some issue introduced by the coarse plate. I guess mine must be relatively flat, or out of flat in benign ways.

[Raney Nelson]

I use a DMT to flatten my stones, and occasionally as a lower grit stone for blades. Mine is flat enough for flattening my waterstones - but I had to return one that was not flat before I got this one. I also find that there is an almost immediate decrease in the aggressiveness of the DMTs as the coarsest level of diamonds are worn away. I'll buy an Atoma diamond on steel plate when the DMT gives up the ghost - by all accounts, they're much flatter.

For remaking a bevel, depending on the application I use any/all of the following: bench grinder, Disc sander, and 80 grit on a surface plate for sensitive steels (japanese blades) or if I need flat.

[george wilson]

Do you guys know that #1 grit sandpaper is one large rock glued in the middle of a sheet of paper?:)

[dan sherman]

I think some background info is in order...

As some have probably figured out by now, I'm a newbie When it comes to neandering. I own 2 block planes, 2 bench planes, and 4 bench chisels all acquired within the last 4 months. I've been using the ss method (had everything needed on hand), and I can easily get a plane blade sharp enough to shave hairs. The progression of grits I've been using is as follows:


120 grit to establish the primary bevel
320 or 400 grit to refine the primary bevel
600 grit to rough out the secondary bevel
1000 grit to refine the secondary bevel
2000 grit to finish of the secondary bevel
HF green polishing compound

I have two issues with ss. First, over time it will cost more than the other methods, and I hate spending more money than I need to, even if that means I have to spend more up front. Secondly, it seems slow if you have a lot of rough work to do. Of course this is because the grit breaks down and becomes finer. Now I can switch out the old paper for a new sheet, but that starts driving up the cost.

Thus I've spend the last week or so learning about the pros and cons of the various sharpening methods, and decided upon Naniwa super stones for intermediate and fine work. I'm still up in the air on what to use for course work, as it seems everything except the bench grinders has drawbacks. My bench grinder is set up for high cobalt hss (metalworking tool bits), thus I would need fit another grinder into my already cramped shop.


Does anyone have experience with Naniwa diamond stones? it sounds like they are made like a Shapton glass stone only with diamond abrasive instead of ceramic.

Our Naniwa #600 Grit Diamond Water Stone allows you to rapidly sharpen any kind of blade. It is particularly effective on those made of high speed steel, titanium and ceramic. State of the art techniques makes it possible to sinter the 1mm thick diamond layer onto a flat aluminum base in a single step. The closely graded diamond abrasive gives a fast cutting action, yet leaves a consistent scratch pattern on the surface of your tools.

[Jim Koepke]

I think some background info is in order...

As some have probably figured out by now, I'm a newbie When it comes to neandering. I own 2 block planes, 2 bench planes, and 4 bench chisels all acquired within the last 4 months. I've been using the ss method (had everything needed on hand), and I can easily get a plane blade sharp enough to shave hairs. The progression of grits I've been using is as follows:


120 grit to establish the primary bevel
320 or 400 grit to refine the primary bevel
600 grit to rough out the secondary bevel
1000 grit to refine the secondary bevel
2000 grit to finish of the secondary bevel
HF green polishing compound

I have two issues with ss. First, over time it will cost more than the other methods, and I hate spending more money than I need to, even if that means I have to spend more up front. Secondly, it seems slow if you have a lot of rough work to do. Of course this is because the grit breaks down and becomes finer. Now I can switch out the old paper for a new sheet, but that starts driving up the cost.

Thus I've spend the last week or so learning about the pros and cons of the various sharpening methods, and decided upon Naniwa super stones for intermediate and fine work. I'm still up in the air on what to use for course work, as it seems everything except the bench grinders has drawbacks. My bench grinder is set up for high cobalt hss (metalworking tool bits), thus I would need fit another grinder into my already cramped shop.


Does anyone have experience with Naniwa diamond stones? it sounds like they are made like a Shapton glass stone only with diamond abrasive instead of ceramic.


For most of my sharpening, it is just a few minutes on the 4000 and 8000 stones. If a blade has gone too long without sharpening, then maybe down to the 800 or 1000. If there is a bad nick or a blade that needs a lot of sharpening, then I will switch to a long strip of abrasive or a powered abrasive.

Because of the extra work involved with getting to the lower grits, my habit is to sharpen a little often.

jim

[Derek Cohen]

The progression of grits I've been using is as follows:

120 grit to establish the primary bevel
320 or 400 grit to refine the primary bevel
600 grit to rough out the secondary bevel
1000 grit to refine the secondary bevel
2000 grit to finish of the secondary bevel
HF green polishing compound

Hi Dan

Jim's comments are very pertinent. I would go even one step further - my most used stones are Shaptons 1000 and 12000. I frquently do not use anything between. The reason is that I am honing microbevels. There is no need to do the amount of extra refining that you do. Too much wasted time and energy from my perspective. With a microbevel you can remove scratches of a 1000 very quickly with a 12000. No need for more. I do have 5000 and 8000 Shaptons as well. The 5000 comes out when the "micro" is no longer micro, and the 8000 rarely comes out as the 12000 works as fast.

I've found that having a flat reference on the coarser grits is more important than having a flat reference on the finer grits

Wilbur ... absolutely spot on.

A coarse stone will shape the steel far, far faster than a polishing stone will do. So, get the 1000 flat and work the steel flat ... and then there is less work to do with the polishing end of the spectrum.

I do have the Shapton diamond plate. I had tried it out when demonstrating sharpening on the LN stand at a woodshow in Perth about 15 months ago. I had my 10" DMT Duostone (using the extra coarse side) for comparison, and the Shapton blew it away. A couple of months later I was offered a brand new diamond plate at an estate sale, so acquired it at a healthy discount. If I had not I would have still been happy with the DMT. Mine is flat. The Shapton diamond plate's extra flatness is probably not really that significant, and time will be the only way I will tell if the diamonds wear. It is just nicer to use.

Regards from Perth

Derek