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  1. #1
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    Default How to Sharpen a Plane Blade Part2: How to sharpen the front side.

    How to Sharpen a Plane Blade Part2: How to sharpen the front side (bevel) of a new blade using a honing guide, and how to manage the stone surface.

    After the ura-oshi process, we are ready to sharpen the bevel of the blade. New plane blade's angle of the blade is always too acute. I have heard that this is because of two reasons. One is that the blade looks more appealing with more ji-gane showing, and another is that, for more expensive blades, when the professional sharpeners (Sui-ken-ya: Water-sharpener) perform uradashi before uraoshi, it is easier when the bevel is wider.

    This is my way, but basically for brand new blades, I donít start hand sharpening in the beginning. I need to use a honing guide to aid the angle. Until there is enough bevel area created to maintain the flat with freehand on the stone, I need to keep using the honing guide. Since I prefer hand sharpening, it is quite frustrating to set the jig every time when I sharpen, but otherwise Iíd have to waste 3mm worth of steel by grinding off the tip and make the angle less acute, and I donít want to do that. I can talk about pros and cons of various honing guides, but Iíll keep that discussion for later article.

    So, first of all let me explain how to sharpen using a honing guide. You might think that there is nothing to it to honing guide sharpening, oh, but yes there is! Let us assume that the blade has reasonable edge on already done by the Sui-ken-ya, but the bevel is rounded (this is always the case), and you want to fix that and sharpen the edge using a finer stone to make it sharper. I will explain how to make the edge reasonably sharp using up to med fine natural stones. Unless you are after single digit micron thin shaves, this will make the edge sharp enough for ANY kind of job.

    I will list the grit and the brand of the stone for reference, but it doesnít have to be these particular ones. But it is worth noting that better stones cut far better thus easier to work with, so I recommend not to be stingy when choosing the brand. When it comes to sharpening alloys, cheapest stones wonít cut at all! The steel will glide on the surface of the stone as if you were trying to sharpen a piece of glass on the concrete block.

    1. Coarse synthetic stone. #220 Shapton Professional Series.
    2. Coarse synthetic stone. Norton super cheap stone from local hardware store. I prefer this stone to fix other stones, since these are basically all glue and super hard. Which means, less cutting strength so cannot be used for sharpening, but retains the flat longer.
    3. Med coarse synthetic stone. #1000 Shapton Professional Series.
    4. Med coarse synthetic stone. #2000 Bester.
    5. Med coarse natural stone or #4000. Aoto(Blue stone).
    6. Fine synthetic stone. #8000 Kitayama.
    7. Med fine finishing natural stone. Oohira Namito.
    8. Straight edge rule to check the condition of the surface.
    9. Honing guide.

    Now let us begin!

    1. Flattening the stone surface.

    This is the most important step when sharpening. Unless the stones are absolutely flat, there is no way you can sharpen the blade to a super keen edge. You start off by submerging the stones (1&2) in the water until there are no bubbles coming out from the stones. When both stones are wet enough, you place one stone on the bench and another on top of it so that both stonesí sharpening surface face each other. Then you move the top stone as shown in the drawing rubbing against the one below, and this will create the flat surface for both stones. Ultimately if you can prepare three stones, and do the same process it will be even flatter, but I personally donít feel this necessary.



    2. Checking the surface with a straight edge rule.

    Until you are used to managing the flat of the stone, it is better to constantly check the surface with a rule. It is important to use an accurately straight edged rule, because normal rules are not so straight as you might expect. There is a straight edge specifically used to check the condition of the sole of the plane block, and these are very accurate. Check the flat in various directions as shown.




    3. Start sharpening.

    Set the blade onto the honing guide to your preferred angle of the blade. Since the roller will drop from the stone if you go too far down, you need to rotate the stone and start from the other side of the stone to use the entire surface of the stone. It is very important to press the tip of the blade as much as possible. I sometimes even scrape my tip of the finger without noticing because my fingers get to close to the tip. If it is the very first time you sharpen the blade, you will only need to sharpen until the whole width of the blade touches the stone. Only about 1mm to 2mm from the tip needs to be sharpened, as if you are making a second bevel. But I will explain how to sharpen after certain amount of bevel has been created.

    As the rollerís axis cannot be "accurately" positioned in the center, you will feel this very slight rocking motion if you pay enough attention. When it is tilted to the steel side of the bevel, you feel less resistance moving the honing guide, and when it is tilted toward the iron side, you feel the stone biting on the iron thus gives you more resistance. If you keep the numbers of repetition the same between these two, you would end up grinding more iron than the steel, so what you need to do is spend extra repetitions when you are grinding the steel side.
    You should divide the stone into perhaps 6 sections, and repeat about 30 laps for the steel part and 20 laps for the iron part for each section. You keep repeating this for maybe 3 sets on #1 stone, and then use the #2 stone to fix the surface. Keep repeating this until the mark on the bevel become uniform. For the last couple of laps, decrease the pressure you apply to the blade, and try to erase the coarse marks as much as possible. This will decrease the time and effort spent on the next step. Do this at the end of each stone.



    Last edited by Groggy; 27th Mar 2007 at 07:22 PM. Reason: Changed font to Arial for readability

  2. #2
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    4. Med grit sharpening.

    It is basically the same to the rough grit sharpening. Shapton med grit stones are very dense, so there is no need for submerging. Simply watering it will do. But Bester stone needs to be submerged for about 1 to 2 mins. (Bester stones are my most recommended stones for now. I personally like this stone much better than the Shaptons, because Shapton stones tend to get clogged easier than Besters. And even with the #2000 grit the cutting strength is as strong as Shapton's #1000. Also the size is larger and the price is cheaper, so there is nothing more to ask. Chiyozuru specialist, Mr. Tsuchida recommended me these stones and since then I am hooked.)

    You do the same process as described in rough grit sharpening, but this time you should use both 3&4 before you rub them against each other. You keep repeating until the burr is created at the back of the tip. Make sure the burr is created enough from one side to the other for the whole width of the blade. Also, you need to make sure that all marks created by rough grit stones are erased, otherwise when you reach the polishing phase these deep marks will start to show and it would be impossible to erase with the polishing stones, thus youíd have to go back to med grit stone again wasting much effort. It takes a bit of getting used to detecting the leftover marks, but as long as you know what you are looking for, youíll start to see in no time.

    5. Med grit natural stone. Polishing phase starts from here.

    You can use #2000 stone to fix the surface of this stone, and do the same process as described above. Again you need to make sure all the marks from the prior grit are erased. Pay extra attention here.

    6. Fine synthetic polishing.

    Polish up the bevel erasing all the mark from the prior stone. Then flip over and VERY GENTLY polish the tip of the back to get the burr off. If you press hard onto the stone when you are getting the burr off, it will cause to create micro chips, so you need to gently rub only the burr off. Wash the surface of the stone and clean all the burr off from the surface, flatten the surface a little, and polish the bevel again.

    7. Final polishing with med fine natural finishing stone.

    The mark created by the synthetic polishing stone is gleaming shiny. The natural finishing stone will make this gleam more hazy. This hazy look is called Kasumi-shiage (Hazy-finish). Polish up the bevel until the iron part becomes light hazy gray rather than silver, and the steel bright with no apparent hairlines. Then flip over the blade and polish up the back, making sure that the whole breadth of the tip gets hazy. Apart from the tip it doesnít have to be hazy, because the tip is all that matters. Remember to keep the pressure on the tip of the tip, but not too high as to cause scratch.
    Now your blade should be razor sharp! Take it off from the honing guide, wash it and dry it thoroughly, and oil it with camellia oil or similar.
    Last edited by Groggy; 27th Mar 2007 at 07:27 PM. Reason: change fonts to arial 2

  3. #3
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    Thanks, soatoz, very interesting reading


    Cheers...............Sean


    The beatings will continue until morale improves.

  4. #4
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    Good to have a new thread started. Thanks Soatoz.

    One question. When using a coarse stone to flatten the surface of other finer stones, is it very hard to thouroughly remove all the (coarser) grit from the stone you have been flattening? How is it best removed?

  5. #5
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    Quote Originally Posted by willie View Post
    Good to have a new thread started. Thanks Soatoz.

    One question. When using a coarse stone to flatten the surface of other finer stones, is it very hard to thouroughly remove all the (coarser) grit from the stone you have been flattening? How is it best removed?
    Hi Willie,

    Sorry, I wrote this in a hurry so it is kind of unorganized.

    The Norton coarse stone is only used to fix coarse stone's surface. All other stone's surface is fixed by #1000 or #2000.

    I will explain how to manage finer finishing stones on the next coming post, "How to hand sharpen a plane blade", but basically you use #2000 or diamond stone to fix the surface, and then polish it up with a finer grit stone close to the fineness to the stone you are polishing, such as Nagura stones. But for finer finishing stones you rarely need to fix the surface. Polishing with Nagura stone should keep it flat.

    The next post will be a very detailed artcile. I don't think this kind of article has ever been written, not even in Japanese. It could be that some of the stuffs I know is something people want to keep to themselves. Anyway, stay tuned.

  6. #6
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    I read that you need 3 stones to make all 3 ideal flat (book: Foundations of Mechanical Accuracy - Wayne R. Moore). I try to make 2 artificial stones flat and all I have done is mess.

  7. #7
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    Quote Originally Posted by rapsod View Post
    I read that you need 3 stones to make all 3 ideal flat (book: Foundations of Mechanical Accuracy - Wayne R. Moore). I try to make 2 artificial stones flat and all I have done is mess.
    Yeah, this kind of thing can happen as shown below, depending on the eveness of the stone. But the harder stones tend not to become like this, and usually the middle part of the stone gets concaved, so it rarely becomes like this. It usually become like this if you only use one stone for sharpening and fix that stone with another unused stone. So you could avoid this to happen by using both stones before fixing.

    If they become like this, they can still be managed by rubbing as shown below. You need to control the pressure a little, but it shouldn't be too severe. Also as I have explained above, it is important to fix the stones quite frequently, especially for the coarser stones.

    So I think it's a matter of preference. If you think having to pay attention to the pressure distribution is bothering but don't mind preparing 3 stones, then you can do that, and vice versa. I myself don't have any problem with 2 stones, so I only prepare 2. I have enough stones around my kitchen sink, so I don't want to increase anymore!

    Keeping the stones flat enough is the MOST important aspect for quality sharpening, so I think it is worth while spending time discussing these kind of issues. If anyone has any kind of problem sharpening, feel free to share your problems here, and if I know how to manage that problem I'd be happy to share it with you.

    Thanks.

    Last edited by Groggy; 27th Mar 2007 at 07:23 PM.

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