# Plans to thin an SRS15 santoku



## chiffonodd (Dec 23, 2015)

I've got an Akifusa SRS15 santoku that I usually keep on hand for smaller acidic and/or sticky stuff like shallots and garlic -- can just prep that portion of the meal and leave aside. Bad habit maybe but sue me.

Anyway, I used it to prep a bit more than the usual the other day, including broccoli, some hard root veggies, onion, garlic, etc. Initial cuts are just fine as the edge is quite sharp and stable. No surprise given the SRS15 core. But after that, the knife just does not really cut well. It does not glide through food at all. I had to use two hands to get through some parsnip lengthwise it was wedging so bad.

This is not a problem with the edge I am convinced. I mean the edge is a little banged up in spots and could have a couple very small microchips sharpened out, but I am not very happy with what I have (amateur-ly) diagnosed as the geometry of this blade. There is very little taper and it seems too thick behind the edge. I am interested in thinning it but wanted to get peoples' thoughts on the best way to proceed.

I have a 120 grit shapton, 220 grit king, but then have only a 1K ohishi. Smartest thing would be to use the 220 I imagine so I don't off too much too fast, focusing behind the edge, using sharpie marker to track? I'm not going to be able to regrind the entire knife to out a decent distal taper on it . . . But maybe I can at least improve the thinness behind the edge a bit??

And then wet-dry sandpaper to recreate the brushed/satin finish? No fingers stones but should be able to get a fairly uniform and fine scratch pattern that approximates the original finish.

Anyway here are some pics. You can see the edge bevel is too wide, a good indicator of the knife being too thick.

*Edge*







*Not much of a longitudinal distal taper...*






*Decent tape from spine to edge but too thick right behind edge!*


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## psfred (Dec 23, 2015)

Probably wedges really badly -- I use a carrot to test. If a thick slice results in a crunching sound, it's too fat.

That one needs the shoulders tapered back, at least to my inexperienced eye. I cannot give you much guidance as I've only thinned really crappy stainless knives in at attempt to make real knives out of them, but I think if you concentrate on the upper end of the bevel and grind at about 5 degrees you will greatly improve the cutting ability without taking much metal off.

Someone who actually knows what they are doing will correct me if I'm wrong, but I would personally try for a stripe a couple mm wide starting a mm or so above the edge to start with and see what that does for you. Of that's good you can stop, or if not you can grind a bit closer to the edge at the same angle.

Whatever you do will work better than me trying to grind a primary bevel in soft stainless that had no taper at all from spine to edge bevels....

Peter


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## Benuser (Dec 23, 2015)

A typical case of some neglect, where only the very edge got sharpened and the geometry overseen. I would start with automotive sandpaper on linen, P120. Use some pressure. Most stones clog with soft stainless. Use hard rubber or soft wood as backing to avoid facetting. I guess you will get scratches on at least 1/3 of the face.


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## Tobes (Dec 23, 2015)

I've got an Akifusa petty which has the same problem, very sharp but no flow cutting through denser stuff...performance way behind my Ashi or Schanz pettys...never sharpened it so no neglectful upkeep of the edge, came like that right OOTB...also thinking about thinning it out a bit


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## chiffonodd (Dec 23, 2015)

Benuser said:


> A typical case of some neglect, where only the very edge got sharpened and the geometry overseen. I would start with automotive sandpaper on linen, P120. Use some pressure. Most stones clog with soft stainless. Use hard rubber or soft wood as backing to avoid facetting. I guess you will get scratches on at least 1/3 of the face.



Do you mean to sand the blade behind the edge with strokes parallel to the edge? Believe it or not this thing was sharpened only once and pretty lightly at that.


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## Tobes (Dec 23, 2015)

chiffonodd said:


> Believe it or not this thing was sharpened only once and pretty lightly at that.



+1, exactly my experience


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## Pensacola Tiger (Dec 23, 2015)

Benuser said:


> A typical case of some neglect, where only the very edge got sharpened and the geometry overseen. I would start with automotive sandpaper on linen, P120. Use some pressure. Most stones clog with soft stainless. Use hard rubber or soft wood as backing to avoid facetting. I guess you will get scratches on at least 1/3 of the face.



Neglect? Probably not.

All the Akifusa knives I have handled were quite thick behind the edge OOTB and required attention to be decent cutters.


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## chiffonodd (Dec 23, 2015)

Pensacola Tiger said:


> Neglect? Probably not.
> 
> All the Akifusa knives I have handled were quite thick behind the edge OOTB and required attention to be decent cutters.



I would love to see some gesshin kagero comparison pics right about now if anyone has them.


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## Benuser (Dec 24, 2015)

chiffonodd said:


> Do you mean to sand the blade behind the edge with strokes parallel to the edge? Believe it or not this thing was sharpened only once and pretty lightly at that.



My remark about neglect was not appropriate, sorry for that. I would thin it with the same motion as with sharpening. With sandpaper only use edge trailing strokes, though, to avoid slight overgrinding when the sandpaper rolls up.


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## berko (Dec 24, 2015)

i still wonder what knife i bought last year, quite the difference...

http://www.kitchenknifeforums.com/s...-this-an-akifusa-harayuki-artisan-ikeda/page2


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## KitchenCommander (Dec 24, 2015)

My Artisan 210 Gyuto shows similar geometry to the OP photo. The edge bevel was enormous out of the box, but I think it was because the shoulders were blended some with the blade face. It was sharpened to a nice high 6000 ish grit because my 6K stone comes very close to the factory edge finish, but even for its lack of stunning geometry, it still cuts well for my needs, and I actually like it very much. I would start by knocking off the shoulders of the bevel first, unless you just want to thin it out.

Thinning will probably make the knife a better cutter overall, but if you want to start slow, just blend the shoulders of the bevel in a bit, and the knife should cut better than before. I am satisfied with my Artisan as it is (for now) but when I get the skills and time, it will be thinned properly at some point.


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## chiffonodd (Dec 24, 2015)

KitchenCommander said:


> My Artisan 210 Gyuto shows similar geometry to the OP photo. The edge bevel was enormous out of the box, but I think it was because the shoulders were blended some with the blade face. It was sharpened to a nice high 6000 ish grit because my 6K stone comes very close to the factory edge finish, but even for its lack of stunning geometry, it still cuts well for my needs, and I actually like it very much. I would start by knocking off the shoulders of the bevel first, unless you just want to thin it out.
> 
> Thinning will probably make the knife a better cutter overall, but if you want to start slow, just blend the shoulders of the bevel in a bit, and the knife should cut better than before. I am satisfied with my Artisan as it is (for now) but when I get the skills and time, it will be thinned properly at some point.



So maybe just an issue with this OEM knife? You know at first I read your post as referring to an "Artifex" which of course sent me over to the other site. Checked out the choil shot of the ultimatum there:






Yikes! Anyway hopefully ok to have reposted that pic. Mods please delete if improper.


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## harlock0083 (Dec 24, 2015)

chiffonodd said:


> So maybe just an issue with this OEM knife? You know at first I read your post as referring to an "Artifex" which of course sent me over to the other site. Checked out the choil shot of the ultimatum there:
> 
> 
> 
> ...



Is that thing bent to the right or is it just me?


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## Pensacola Tiger (Dec 24, 2015)

harlock0083 said:


> Is that thing bent to the right or is it just me?



No, it's not bent. It is flat on one side, and your eye misinterprets it as bent.


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## chiffonodd (Dec 24, 2015)

harlock0083 said:


> Is that thing bent to the right or is it just me?



Just the asymmetry I think, but another good example where thinning would really benefit performance


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## Keith Sinclair (Dec 24, 2015)

Think quite a few persons here have thinned Akifusa's. They do tend to be rather thick. As mentioned you can start by just thinning behind the edge first before putting on your final bevel every time you sharpen.

I did thin my 240 gyuto that left the bottom half of blade contrasting. I evened it up by hand sanding took it to a 320 grit kind of a satin finish. Then put the edge back on. The SRS-15 steel can always be taken to a polished very sharp edge.


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## chiffonodd (Dec 24, 2015)

keithsaltydog said:


> Think quite a few persons here have thinned Akifusa's. They do tend to be rather thick. As mentioned you can start by just thinning behind the edge first before putting on your final bevel every time you sharpen.
> 
> I did thin my 240 gyuto that left the bottom half of blade contrasting. I evened it up by hand sanding took it to a 320 grit kind of a satin finish. Then put the edge back on. The SRS-15 steel can always be taken to a polished very sharp edge.



Did you thin on stones or with sandpaper as suggested above? If on stones did you have any trouble with the soft stainless cladding gumming things up?


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## Pensacola Tiger (Dec 24, 2015)

chiffonodd said:


> Did you thin on stones or with sandpaper as suggested above? If on stones did you have any trouble with the soft stainless cladding gumming things up?



Soft stainless cladding just _feels_ gummy - it doesn't actually gum things up, though the sheer amount of steel you are removing during any thinning operation may load the stone and require lapping. That's one reason I like to use Atoma plates for thinning.


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## chiffonodd (Dec 24, 2015)

Pensacola Tiger said:


> Soft stainless cladding just _feels_ gummy - it doesn't actually gum things up, though the sheer amount of steel you are removing during any thinning operation may load the stone and require lapping. That's one reason I like to use Atoma plates for thinning.



I have an atoma 140 but I'm scared to start on that :shocked3: Might even start with a 1K stone with marker on the blade just to get a visual of where steel's being removed in order to find the correct angle, then drop down to a 220. Slow and steady for this first attempt!


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## Pensacola Tiger (Dec 24, 2015)

chiffonodd said:


> I have an atoma 140 but I'm scared to start on that :shocked3: Might even start with a 1K stone with marker on the blade just to get a visual of where steel's being removed in order to find the correct angle, then drop down to a 220. Slow and steady for this first attempt!



There's nothing wrong with being cautious, but grinding the side of the blade is a lot more forgiving than grinding the edge, where an Atoma 140 can do some damage in unskilled hands. I'm willing to bet that you'll be moving to the Atoma after trying to thin with a 220. 

Keep in mind that to be effective, you have to thin at least the lower one-third of the blade.


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## chiffonodd (Dec 24, 2015)

Benuser said:


> My remark about neglect was not appropriate, sorry for that. I would thin it with the same motion as with sharpening. With sandpaper only use edge trailing strokes, though, to avoid slight overgrinding when the sandpaper rolls up.



No apologies needed I did not take it as meanspirited criticism, just feedback on a possible issue. Nothing should be ruled out with me lol


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## Keith Sinclair (Dec 24, 2015)

chiffonodd said:


> Did you thin on stones or with sandpaper as suggested above? If on stones did you have any trouble with the soft stainless cladding gumming things up?



I used to do thinning with the 140 Atoma, found that thinning on coarse stones will dish the stone quick. When got into making handles bought a 1X42 sander. At first was afraid to thin on the sander, started with some cheap old American carbons like Dexters. Keep a bucket of water to dip the blade. On the sander never let the edge come in contact with spinning belt just the metal behind the edge. Do it without gloves finer touch & can feel any heat. After thinning can touch it up on the stones. Now use the belt all the time restoring knives, hatchets, Axes and Machete's.

Don't know how the pro's do it, have gained confidence with practice.


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## chiffonodd (Dec 24, 2015)

Well I started out on the 220 and quickly grew bored, just like ptiger predicted. Droped down to the atoma 140 and felt it was loading pretty fast, knife just started gliding. So I went to the shapton 120 and then I started seeing some serious cutting action. Stone was really grabbing onto the steel. This is after about an hour of work all told...






Still a ways to go but looking better than the first pic for sure.


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## chiffonodd (Dec 24, 2015)

Comparison shot after 1 hour . . . slow going!!


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## XooMG (Dec 25, 2015)

Good luck with thinning...just don't make it too flat.


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## Keith Sinclair (Dec 25, 2015)

Nice choil shots should cut better already. Have a merry christmas:hula:


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## chiffonodd (Dec 25, 2015)

XooMG said:


> Good luck with thinning...just don't make it too flat.



Yeah I think I'm gonna try to focus much more on the first centimeter or so behind the edge from here on out -- not flatten out the blade face any more. Time to bust out the sharpie.


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## chiffonodd (Dec 25, 2015)

keithsaltydog said:


> Nice choil shots should cut better already. Have a merry christmas:hula:



Thanks sir! And mele kalikimaka to you :biggrin:


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## chiffonodd (Dec 25, 2015)

Three hours later . . . fingers hurt :dazed:


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## psfred (Dec 25, 2015)

Your fingers may hurt, but I bet the knife cuts MUCH better now!

Peter


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## XooMG (Dec 25, 2015)

I recommend testing it periodically to ensure it cuts the way you like. A choil shot can look fantastic and cut awfully (or v.v.).

More than once I've thinned too aggressively and had to fix it by convexing and losing a fraction of a millimeter of height. Choilies won't always show the difference between a sticky cutter and a silky one.


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## Asteger (Dec 26, 2015)

Looks much better in the newest pic and was very thick before. Looks thinned enough to me, and you can just set an edge bevel at a steeper angle similar to the one on the back of the blade now. 3 hours to get to this point sounds reasonable. Did you find the grind was consistent as you thinned? If not thinning can become a pain and take longer.

Of course now you'll have to re-finish if you care about that too


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## chiffonodd (Dec 26, 2015)

[Edit] response deleted because pics showing up weird, will correct and repost


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## Benuser (Dec 26, 2015)

Found the pix rather OK.


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## chiffonodd (Dec 26, 2015)

Asteger said:


> Did you find the grind was consistent as you thinned?



I think the grind was pretty consistent, as should be expected with this knife. Didn't feel any pronounced high or low spots. Lack of uniformity in the thinning marks (see below) are due to learning curve on my part I'm sure -- i.e., finger placement, pressure, angle, number of strokes, etc. You can see I was trying to avoid scratching up the kanji for example. And that i really wanted to concentrate on thinning out the tip tthink I hit all the right spots near the edge though. Didn't remove much steel higher up the blade so the irregularities are pretty much just cosmetic and will be sanded/polished out.







One thing nice is that you can see that the terrible wide edge bevel is now gone. Put on a much smaller bevel at 1K, which is visible here. Got some testing/tweaking, refining, and refinishing to do!


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## chiffonodd (Dec 26, 2015)

Performance test!

Starting with carrot in a variety of cuts (*disclaimer: getting my end grain board back next month *)






Performance is not perfect but it is MUCH improved. The knife is night and day from where it was before. The difference is especially notable when making initial lengthwise cuts in a section of carrot to create a stable cutting surface -- the blade is only 180mm and in such cuts, there is so much contact between the blade and the product that the new geometry makes a big difference in reducing wedging and stiction. Brunoise is easy in terms of cutting, but limited by the short length of the blade. Cutting rondelle was the easiest -- minimal blade contact, sturdy target (doen't "give" and disperse the force of the cut like dicing julienne into brunoise), passed through extremely easy, almost no resistance. A whole new knife!

Then onto onions . . . 






A little spoiled here by my experiences with the grind on my ginga and kochi, but again, much improved performance. Initial vertical cuts to make that dice in the back were very easy. The horizontal cuts were not so easy . . . the blade tended to grab onto the partially sliced onion and spread it as it went through. Do not have this problem with the ginga or kochi. One problem I think is that the edge is quite toothy at the moment and needs to be refined, and much of the blade still has scratches. The toothy end and unpolished blade are gripping the partially-sliced lightweight onion when cutting in this direction. Hopefully once I take the edge all the way through a progression and polished the blade, this problem will alleviate.

Finally, slicing onion was pretty easy. Tested different parts of the blade. Toward the tip and toward the heel are both easy. This is where I think I spent most of the work thinning. The tip because I simply wanted to thin the tip out and the heel because it needed the most work. Well now I want to go back and do some more work mid-section. 

Anyway, got some more opportunities coming later tonight for additional testing. Gonna roast some romanesco and break potato down for a mash at the in-laws. Also going to get to mince some herb. 

Why didn't I try this earlier?? This is so much fun :bliss: Anyway thanks KKF for watching.


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## rick_english (Dec 27, 2015)

Thanks for the show!


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## XooMG (Dec 27, 2015)

Yeah, drag and sticking can really reduce a blade's cutting ease.

Be careful with thinning...it is addictive...and then you'll get addicted to taking useless choil shots!


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## Asteger (Dec 27, 2015)

In ways it isn't hard to thin and it's also nice to see the results at the choil. But the challenge is at the front of the blade, around the curves, and dealing with grind mishaps. Feels good when you pull it off.


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## Kippington (Dec 27, 2015)

^

And then there's polishing up the mess you've made...

Then feeling the need to mess it up again only a few sharpenings later!

Like many members here I started using a belt grinder instead of stones to modify the edge geometry on my knives. One of the many advantages of the grinder is that, instead of scuffing up the sides, you end up with that brushed metal look similar to the Konosuke HD2s, the Sukenari Hairlines and many others. I know some people don't like it, but I've grown to really like this finish and am happy to leave it as it is:











There are disadvantages to using a grinder, of course. One of which is wanting to spend more and more money on a new and better one! :O

Really good work on your Akifusa by the way! I'm happy you've gone and improved a factory grind, albeit falling deeper down the sharpening rabbit hole!


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## _PixelNinja (Dec 27, 2015)

Now I want a belt grinder. Ugh.


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## chiffonodd (Dec 27, 2015)

Asteger said:


> In ways it isn't hard to thin and it's also nice to see the results at the choil. But the challenge is at the front of the blade, around the curves, and dealing with grind mishaps. Feels good when you pull it off.



I also found it difficult to do the same thing on both sides of the blade. I don't switch hands while sharpening/thinning, so it's difficult to apply the same pressure in the same places. I'm right handed so metal removal on left side of the blade was biased toward the heel and edge. Right side of the blade much more up the blade face near the tip. All things to work on evening out in future efforts.


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## chiffonodd (Dec 27, 2015)

XooMG said:


> Yeah, drag and sticking can really reduce a blade's cutting ease.
> 
> Be careful with thinning...it is addictive...and then you'll get addicted to taking useless choil shots!



Wicked. Must . . . resist . . . photography . . . rabbit hole . . .


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## chiffonodd (Dec 27, 2015)

Kippington said:


> ^
> 
> And then there's polishing up the mess you've made...
> 
> ...



lol my wife now looks at me suspiciously whenever I'm using my phone, knowing you are all tempting me with expensive new gadgets. "Are you on the knife forums again??!!" Yes, dear...


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## chiffonodd (Dec 27, 2015)

Working on refinishing now. I don't have any finger stones or anything so I just tried to sand out the thinning scratches with multiple grits of sandpaper. I thidnk it was 80, 120, 150, 220, 400, 600, 800, 1000, 1200, 1500, and 2000 grit, but I'm too tired to go back and check. I can really see why people buy power tools.

Here's a before and after to show the progress on the semi mirror finish.

I also took the opportunity to ease the spine and choil with a hobby file set and some more of the sand paper.

Only thing left to do now is put a low edge back on there (sandpaper was not good for the very edge), take it up through a full progression, and I think then a microbevel.

*Lots of scratches to buff out . . .*







*Gettin shiny (reflecting some cabinets)*


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## XooMG (Dec 27, 2015)

chiffonodd said:


> Wicked. Must . . . resist . . . photography . . . rabbit hole . . .


Not really necessary, in my opinion. Choil shots can be done with pretty basic stuff. Like a lot of things, it's mostly technique.


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## Asteger (Dec 27, 2015)

chiffonodd said:


> I also found it difficult to do the same thing on both sides of the blade. I don't switch hands while sharpening/thinning, so it's difficult to apply the same pressure in the same places. I'm right handed so metal removal on left side of the blade was biased toward the heel and edge. Right side of the blade much more up the blade face near the tip. All things to work on evening out in future efforts.



I always sharpened ambidextrously and would switch, up to a few years ago when I tried to learn 'the Japanese way'. I think to do 2-bev knives well it's really best to switch, like Carter does. However, too late for me to go back.

As traditional J-knives are mostly 1-bevs, I think the non-switching style of sharpening is ingrained because of them. On the bright side, because of the assymetry of the usual 2-bev gyuto and some other 2-bevs, you don't need to spent the same time on the backs compared to the fronts.


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## Benuser (Dec 28, 2015)

Check for steering and act accordingly. By the way, with a belt sander there are some serious safety and heat issues.


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## Kippington (Dec 28, 2015)

Thats some really nice work there chiffonodd, well done! I hope you're happy with where it is at the moment because I can see you've put a lot of work and many hours into it. It puts a lot of things into perspective after you've thinned AND polished it by hand.

I think you'd enjoy documentary if you haven't seen it already. It's about the togishi, a Japanese sword polisher. The level of dedication that goes into this blows my mind. No power tools of course, and I'd love to hear someone try to convince these guys that they should flatten their stones!

[video=youtube;2x5WzIu5iXU]https://www.youtube.com/watch?v=2x5WzIu5iXU[/video]



Benuser said:


> By the way, with a belt sander there are some serious safety and heat issues.



That's a serious 'blanket statement' right there, I could give the same warnings about driving a car! :razz:
Its a potentially complex topic, but the _basics_ of why and how we anneal/quench/temper steel is pretty straight forward and worth learning, even if you're not planning on using a belt sander. That way you can easily work out how not to let any part of the blade get overheated, and learn what would happen if you quite possibly did!


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## chiffonodd (Dec 29, 2015)

Kippington said:


> Thats some really nice work there chiffonodd, well done! I hope you're happy with where it is at the moment because I can see you've put a lot of work and many hours into it. It puts a lot of things into perspective after you've thinned AND polished it by hand.



Thanks! It is a lot of work but you learn so much by these projects. Next phase is going to be more cutting testing to check for steering like Benuser suggested. Probably should have held off on refinishing because may have to make corrections. But it's all good practice. Dunno if I'll ever get to a point where I feel competent without the opportunity to actually study with someone who knows what they're doing but at least I'll enjoy the ride.

Really look forward to watching the documentary - thanks for the link!


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## TurboScooter (Dec 29, 2015)

Kippington said:


> Thats some really nice work there chiffonodd, well done! I hope you're happy with where it is at the moment because I can see you've put a lot of work and many hours into it. It puts a lot of things into perspective after you've thinned AND polished it by hand.
> 
> I think you'd enjoy documentary if you haven't seen it already. It's about the togishi, a Japanese sword polisher. The level of dedication that goes into this blows my mind. No power tools of course, and I'd love to hear someone try to convince these guys that they should flatten their stones!
> 
> ...



Awesome documentary. Thanks for posting it.


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