What do you use for removing a lot of metal?

[wilburpan]

I've been working on a used kanna blade that I picked up on eBay, and am getting fed up with the DMT coarse diamond stone that I have been using for coarse grinding work. For non-Japanese tools it seems to work fine, but when it comes to working the back of the tool, even with the hollow, it takes forever to make any progress. I've found this to be the case with working on the back of Japanese chisels, as well. It seems like even though this is a coarse diamond stone, it cuts at about the same rate as my 1000 grit Shapton.

I've been looking at picking up a very low grit Shapton, like the 120 or the 220, or picking up a coarse natural stone, but one thing I am concerned about is the tendency of coarser stones to dish more quickly than finer grit stones. At least that's something that I don't have to worry about with the DMT stone.

Any suggestions?

[Claw Hama]

The 1000 grit shapton should soon take the meet off your Japanese tools, I use a 1000 grit King on my Japanese tools which should be similar, then 6000 and finish off with a natural stone. Put some cool music on, Sinatra or The Three Tenors, take your time, be patient and enjoy the time.

[Sheets]

Hi Wilburpan,

Yeah, me too. I've definitely decided that the man-made coarse stone (220 King in my case) works faster than the coarse natural stone (omura), but its still slow.:(( One method I use to prevent the 220 from dishing, is working across the surface diagonally as well as parallel (but I still give it a scrape across a flat rock occasionally to make sure its flat).
Like Claw Hama says, that's the way it is. Might as well enjoy it.

BTW, the binsui I have is somewhere above a King 1200 in fineness. The iyoto above that - suitable as a pre-finish (like aoto).

Steve

[wilburpan]

Hi Steve,

Now I remember you mentioning this on the other Japanese tools forum, but since it's down for now, and I couldn't remember what I had read, I thought I'd give here a try.

At least would you say that your King 220 is faster than a 1000 stone?

Claw Hama,

On the back side of the plane blade that I'm working on, the flat behind the edge touches down at the corners, but not in the middle. The grinding that I'm doing is on the hard layer only, which is why it seems to be taking so long. At the rate that I'm going, I'll hear a whole Three Tenors concert and still not get done. Actually, I think I've already hit that point.

Tapping out is not really something I want to try with this particular blade, because the current bevel angle is very shallow, and I'm worried about cracking something.

Thanks,
Wilbur

[Schtoo]

Kanaban and some kind of device to hold the blade well so you can push down hard.

A stick with an attached lip on it to hold the blade, and something to stop it sliding from side to side will work. The proper ones use a wedged clamp doohickey.

Take the kanaban (hunk of milled, soft steel), wet it down with a little water and sprinkle on some coarse silicon carbide grit. For really bad stuff I use #36, but usually #120. Put the blade on there and carefully mash the grit into the kanaban with all your weight. Once the grit starts to bite more than skid about, use it as you would a waterstone, but apply a lot of pressure.

Once the blade starts to catch a little on the kanaban, you are done. You should end up with a lot of metal removed, and because the grit has been progressively crushed, the finish should be very smooth and might be polished.

Takes a little while. Anywhere between 5 and 30 minutes depending on how bad the blade is, what grit you start at and how much pressure/finese you employ.

I usually use a diamond plate I picked up for general grunt work now, but when that doesn't cut it, the kanaban gets a workout.


If you can't easily get the right gear, some coarse valve grinding paste and a piece of cold drawn steel will work just fine. Should cost too much either.

[derekcohen]

Hi Wilbur

I get the best performance from sandpaper-glued-to-glass. If grinding a lot of metal, then I start with 120-, sometimes 80 grit. Move to 240 grit to remove the deep scratches, then on to 1000 Shapton.

I do have a 220 grit King. It cuts well. But I do not trust it to remain flat long enough. I have not used a similar grit Shapton, but I doubt that it would be that much different. The thing about the sandpaper is that the flatness is replicated among the grits, which makes it easier and faster to remove scratches.

I do have a DMT Extra Coarse/Coarse Duostone. The EC is for flattening the Shaptons (now to be replaced by a Shapton diamond lapping plate), with the Coarse side dedicated to metal. It works well, but slower than sandpaper because it is rated at 325 grit.

Go with the sandpaper.

Regards from Perth

Derek

[Woodjoint]

I'm with Schtoo on this one. I have a 220 Shapton and while it does remove metal fairly well it does dish quickly. You spend as much time flatting the stone as you do flatting the blade. The kanaban has always worked for me although if it isn't a lot I use my DMT. One thing more to add is not use very much of the grit and a very little bit of water. The object as it was explained to me is to rub the blade until the paste drys out completely and only then do you stop and look at the blade. It took me a while to realize how little water and grit was necessary.
It does sound like it's time to try tapping out. I ended up with a piece of railroad track with the edges rounded over. You must make sure the blade is supported where you are tapping. Tap with the edge of the hammer or use a cross pean hammer so you are constrating the hits in a very small area. Start high on the soft steel and as you get used to hitting where you are aiming at, work your way closer to the hard steel but never strike anything but the soft steel. Check your progress and the only way to do that is go to the DMT and take a few strokes to see if the steel has moved. You'll be supprised how easy it is and how much faster it is to flatten a plane blade. I do it on all but my smallest chisels as well. :doh:
Just read Derek's reply above (wasn't there when I started writing this) and I agree with him as well, I have used that process as well but I tend to stick to the Japanese methods when I can and after getting the hang of the kanaban I think it's the easiest because you don't have to change grits, just grind it down to a dry paste and you're done.

[Sheets]

Hi Guys (all),

I've not attempted to use only a 1000 (or there abouts, I have 800, 1000 and 1200) to remove a lot of steel. I know lots of people do, but I tend to not want to cause these stones to wear out too quickly (they're not terribly expensive, but still, I'd rather prolong there life). So I've stuck with the coarse stones. I haven't invested in diamond stones or plates because of the cost and I've not really read that they are significantly superior to other stones. And, although I've not used sandpaper on glass, I would as its really a cheap investment.

I've used kanaban (still do) with some of that Lee Valley green honing compound (I know its super fine grit) and it seems to work pretty quickly. I use water to lubricate it and hold it down with a stick, like Stu says. When I have a blade that is pitted from oxidation (a rescue/restoration project from eBay), I need to grind down to the depth of the pits so they don't keep meeting the edge as you sharpen ( otherwise, you just end up with a perpetually messy edge). But I do tap out when the flat is gone otherwise.

As an aside, I like using the natural stones in the medium range because I like to see the activity (hada) in the steel, and fine to get the sharpest edge.

Steve

[Claw Hama]

Ah everybodys in a hurry,think about the little guy who made it, took his time beating, welding, tempering.:U

[mic-d]

Why don't you use a slow grinder with a white wheel?

Cheers
Michael

[Woodjoint]

Why don't you use a slow grinder with a white wheel?

Cheers
Michael

Michael, Wilbur is trying to flatten the back of the blade! Not a job for a slow grinder of any kind. Most of us don't even use a grinder on the bevel. With Japanese tools we want a flat bevel.:doh:

[Claw Hama]

:roll:Yes Mickyd, when I saw that last night, I couldn't respond. My fingers froze, I started to sweat, I didn't know what to say (diesn't happen very often). Some of us pay from $100 each up, way up $$$ for these very hand made chisels the makers would literaly have a heart attack if they thought you were using any sort of grinder on them. Even the wrong water stone would give them palpatations.
Any sort of heat can cause delamination and a host of other fatels.:U

[mic-d]

Michael, Wilbur is trying to flatten the back of the blade! Not a job for a slow grinder of any kind. Most of us don't even use a grinder on the bevel. With Japanese tools we want a flat bevel.:doh:
I'm sorry, I didn't read the post very well, didn't realise the trouble was flattening the back.
I use a slow grinder with a white wheel to hollow grind the bevel of my japanese chisels

CHeers
Michael

[NeilS]

I get the best performance from sandpaper-glued-to-glass. If grinding a lot of metal,



Hi Derek - thanks for that reminder. I have always used that method for flattening the soles of my planes (and to flatten my waterstones before I started to use my diamond plates for the stones). Certainly cheaper than using a diamond plate for heavy metal removal.

Never used a traditional kanaban, but, in a sense, carborundum (silicon carbide) paper attached to a flat surface is the same thing.

Neil

[Woodjoint]

Never used a traditional kanaban, but, in a sense, carborundum (silicon carbide) paper attached to a flat surface is the same thing.

Neil

Not quite!:no: The carborundum powder breaks down into a finer and finer paste until the blade is polished to a "see your face" shine.

Not possible with the paper on glass unless you change the paper to a finer and then finer and then finer grit. :doh:

[NeilS]

Not quite!:no: The carborundum powder breaks down into a finer and finer paste until the blade is polished to a "see your face" shine.


Thanks Woodjoint for the explanation... I guess not that dissimilar to natural waterstones that tend to do a similar thing.

Neil

[derekcohen]

I say this from a theoretical point of view, since I lack the experience of actually using carborundum powder this way ... Would it break down too quickly if you have a lot of steel to remove? There is nothing worse than trying to grind with a too-fine grit. Wasted hours. The advantage of sandpaper is that you can sustain a low grit until it is time to move to a higher one. Comments?

Regards from Perth

Derek

[wilburpan]

Also from a theoretical point of view, since I haven't tried carborundum either, from my experience with that diamond stone that started this discussion, it's not too hard to tell when your method of sharpening slows down if you are trying to get rid of a lot of metal. I would think that if you were using carborundum powder on a kanaban, if you got to that point, you would sprinke more carborundum on, just like if your sandpaper became less effective, you'd get another sheet.

By the way, some sort of combination of tapping out, using the side of the wheel on a Tormek, and 150 grit sandpaper on a granite stone did the trick for me. But I still wish this process could be faster. :wink:

[Clinton1]

I say this from a theoretical point of view, since I lack the experience of actually using carborundum powder this way ... Would it break down too quickly if you have a lot of steel to remove? There is nothing worse than trying to grind with a too-fine grit.


When the grit breaks down, I add a little more grit.
A bit of practice and you work out how long it takes to break down, how much to add, and still be able to take advantage of the fact that it does break down.

[Woodjoint]

When the grit breaks down, I add a little more grit.
A bit of practice and you work out how long it takes to break down, how much to add, and still be able to take advantage of the fact that it does break down.

Yes it does.:U