Professional sharpener here, The knife is dull because he's using a granite board which will destroy your edge faster than anything. Using a soft wood or plastic board is far better for your knives. Honestly not a bad vid. Went about it safely by securing the grinder and the sparks don't mean you have de-tempered the knife. If the colour of the steel of the blade changes, that's when you have removed the hardness. As long as the steel on the kife itself doesn't change color its fine. Early in my sharpening service I used to use the exact same way for my course sharpening as well as removing chips in the blade. Then finished on stones for a finer edge. It works, just not great for the final edge. Rather finish on a 800 or 1k grit stone or higher and then strop
If there is color change that means you messed up the knife very badly. You don't need to go that far to loose some points of hardness and reduce edge durability. According with tempering diagrams 200 degrees is enough to start loosing hardness on most steels. If it's sending glowing sparks the apex is clearly overheating.
@@thiago.assumpcao but also remember that's just the sparks getting hot. Not to mention literally every knife maker I've ever seen make a knife does the majority of the grinding before heat treatment and tempering yes. However they brought grind to a point, they then need to finish the grid to the final thickness and final finish grit they want. Each one of those belts will send sparks out after heat treatment and tempering. Then on the Japanese kitchen knife side if things. They forge, heat treat and temper before any grinding. Then rough finding on water wheels because it's heavy grinding and you're bound to overheat the blade with any form of heavy grinding when not cooled but the water wheels still cause sparks. Then over to the finishing grits which are done differently depending on which maker the knife is done by. Normally either on belts, which produce sparks, or on large buffing wheels which also happen to cause sparks as they take the knives up to about 180 to 200 grit on those buffing wheels. The finishing of the Japanese knives are done without any water cooling and yet Japanese kitchen knives are known as some of the hardest knives out there. While what you said about 200 degrees being enough to start to change the hardness may be true its doesn't affect the edge adversely in any noticeable ways unless you're doing something wrong.
@@tylermelton1746 Sparks dont heat up after leaving the knife. They get that hot during abrasion while in contact with the knife. Heat dissipates so we dont see it on the entire knife. Heat treatment damage by machine sharpening without color change is not only a theoretical issue. Some knives look perfect but don't get a good edge no matter what you do. After grinding off a fair bit of steel knife changes behavior and cuts better. On a less severe case you may have a good initial sharpness but loose edge durability because of hardness loss. Detecting such issues would be quite hard unless you do durability tests. Machine sharpening without water cooling is possible but doing it right takes a lot of time with constant water dipping. Water cooling saves a lot of time.
@@thiago.assumpcao of course it takes a lot of time. But the point I was trying to make is to get that issue you need to be doing something wrong. In this case that would be not regularly cooling the blade. In the case of a grinder fresh disks or belts mean you have to dip less.
Are you guys saying if there's sparks you've gone too hard and it's over tempered the knife and destroys the edge? I just bought a belt sander to sharpen my knives. Didn't think it would soften the edge
This video has been uploaded by someone who clearly has absolutely no understanding as to how dangerous a grinder is. RU-vid needs to be taking shit like this down because its just encouraging ill informed people to behave recklessly
Whoopsie 😬 If possible, I suggest beginners use sacrificial knives or scrap metal or gardening implements like spades and pitch forks. The sparks don’t hurt bare skin but I suggest using protective eyewear and working in a well ventilated space free of highly flammable petro-chemicals.
I use this type grinder wheel to clean up rusty cast iron skillets, etc and to get them like a mirror smooth . Food doesn’t stick if you’ll get the orange peel finish off. Polish it up with grinder then season over campfire or in oven
I normally do this once in a while, maintaining it with a stone or a sharpening rod just before some fine cutting. Can also be used on a machete if want to cut branches in the garden. Have some eye protection as sparks and metal filings will be flying around. Only do if you know how to handle an angle grinder as it is a dangerous power tool.
🧢 your knife had 0 problems cutting the tomato the first time until you started twisting your wrist like you weren't sure how a knife works 😒 why lie in the beginning and where was the cardboard test at the end?
Interesting that the grit started at 80 and finished at 100. I watched a vid yesterday with stones that started the grit at 240 and went to 3000. I suppose the difference is quick and nasty for a potential disposable knife compared to decent and sustainable grind for a premium knife.
for example japanese stones use a different grit system than the west. I tend to start with a 240 grit belt and go up to 600 (not always), and then strop on some leather. This angle grinder method above is a way to get yourself injured (look at the direction it rotates), even a belt grinder needs to be used with caution. Last year a very experienced knifemaker from the US died when the belt caught the knife. Just use sandpaper and some patience if you don't want to invest much. It works fine.
На пять таких операций и нож можно будет выбросить, скорее то что от него осталось. И не дай бог нож упрется в лепестки остриём может закончится очень плохо на такой скорости
Most genius idea I've seen you have all day! Thanks and thank you for warning people not to put the knife in there at a straight angle so it doesn't whip out of people's hands and stab them when they're grinding it... 🤣🤣🤣
Stop using your knife on a ceramic board and your knife will last longer and this type of sharpening knife is bullshit if you like your knifes never sharpen it like this
Just tried this and it worked but I wouldn’t do it on a good quality knife. Really messing up the blade. So easy to make it uneven. Lots of shards of metal. However, after working it carefully, they seem to cut pretty good!
Cool: Endlich eine Methode, jedes Messer schnell und dauerhaft zu ruinieren ... -- na ja, um das Ding aus dem Video ist es nicht wirklich schade 🥴🥴🥴 Und er fängt mit 80er Körnung auf einer Flex-Scheibe an ... Warum nicht gleich mit einer Stahlbürste und dann mit einer 20-Zoll-Feile, Hieb 1??? Feile, Deutscher Hieb 1 = grob: Für grobe Schrupparbeiten viel Materialabtrag und grobe Oberflächen ...
Ответ - никак! После этих извращенных операций наж резать не будет, от слова вооообще! Он будет ПИЛИТЬ, так как на режущей кромке образуется микропила.
Full disclosure!! This is not for little bitches. I repeat, this is not for little bitches. So if you’re not a little bitch, then please excuse @daddydayne little bitches comment
Asi to jde i takto, kdo ale rozumí broušení nožů tak se musí dost smát. Jak například docílíš oboustraného úhlu brusu,souososti a dalších hodnot? Navíc ten nůž takto ,, nabrousíš'' tak 5x a je poloviční.O tom že ti to může snadno rozbít hubu ani nemluvim 🤦
Ширпотреб это не нож! Купите дорогой нож и он прослужит вам долго и честно! Я купил в нашем ТЦ. В Японской лавке нож за 5 тычяч. Жалею что не за 8семь. Качество отменное. Не чета этому хламу!
This is a bad idea; not only is this dangerous as it may grab the knife and throw it out Fo your hands (imagine it hurling at you! 😮) but also that grinder will crest heat which could ruin the knifes temper (they’re heat treated to get to the idea hardness). So just buy a stone and learn how to do that
Если на стекле резать помидоры и поддерживать лезвие ножа в состоянии бритвы , то какая форма его будет через месяц. Он превратится в канцелярский ножечек
Die 1. Tomate war schon sehr reif und weich. Die Haut angehende faltig. Tomate 2 war noch fest und wäre auch mit nicht geschliffenem Messer ohne Probleme schneidbar.
