Global knife sharpening

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  • Hello all, I'm new to the forum and was hoping you are able to clear up a couple of things.


    I am a very keen cook and have been struggling with some james Martin knives for a few years. I have now decided to purchase a global ni set. After trying some other knives these felt the most comfortable, also I love the design.


    Anyway I'm just looking for some advice on how to keep the edge of the knife and then the process once they do need sharpening.


    From what I've read before and after using the knives I should do a couple of passes on my ceramic smooth rod. Is this about right? I am also getting a leather strop so I wasn't sure if using the strop is better to use than the rod.


    When it does come to sharpening the knives I have a couple of Japanese water stones. 400-1000-6000. I doubt the 400 would really be needed but I'd imagine I'd go through the 1000 and then finish on the 6000. Now normally this is where I would stop but after a little research it is then better to steel or strop the knife. I will have either a leather strop or a smooth ceramic steel, which is best to use after the 6000? I would have normally thought the ceramic but I'm reading that the ceramic is equivalent to a 1200grit and seems pointless following the 6000 with the ceramic. I'm also reading that the leather is about 12000 grit so is probably my best bet.


    If you are able to help me have the correct order for sharpening and also advice on what if anything should I be loading the strop with.


    Again I have the global ni knives and I am a home cook so just normal use.


    Also just ordered a beechwood end grain board, I believe this is a good wood for helping to retain the knives edge but your confirmation would be great.


    Thanks in advance


    Dan

  • Touching up any blade on a regular basis is certainly a good idea, much better than leaving it to go blunt like my Mrs does. lol


    Using a wooden chopping board is very wise too, again my Mrs won't stop using a glass one so I'm on a losing battle hey.

  • A good 6000 edge (=apexed and burr free) should be more than good enough for any cooking need. You do not need anything more. An edge like that can be maintained in the kitchen with a ceramic rod. You can also your a strop to maintain it if you like. They do roughly the same thing: straighten and polish the edge. But a ceramic rod is easier to keep clean in the kitchen.

  • Thanks for the super quick responses.


    I believe I've got the technique correct and my crappy knives seem to come up extremely well. I'm pretty sure the burr has gone but that's why I got the strop as I believe this removes the burr further or to a much lesser micron.

  • Hello and welcome, Dan :)


    Once there's a good edge on your knives, a Spyderco Sharpmaker is a quick and easy way to keep the edge tip-top.


    Though, I have to say, getting the knack took a little practice, but perhaps that was just me :SX/

    ..


    ...anyone who rides a bike and loves nature, can never be poor, we will always be happy, no matter what
    Gunther Muller

  • I would go with Paul's advice and purchase a Spyderco Sharpmaker and practice on some cheap knives until you get the knack.
    If you follow this up with a strop & compound you will be able to keep your knives perfectly functional for kitchen duty.
    I have used this method for a good long while now, and it works for me on most knives of varying blade lengths and stock thicknesses.
    Stropping technique, and maintaining a consistent angle is the key.
    TB London is 'the man' re kitchen knife sharpening, is he a member on here @Chui ?
    Welcome to EM Dan.







    "This is my rifle.There are many like it, but this one is mine"


    ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


    Sharpen it like you love it, use it like you hate it.

  • Will take a look at that sharpener. My only issue is I already have stones and a ceramic steel also a strop on route so I was hoping to not spend to much more

    Empty wallets are part of the membership criteria :D;)







    "This is my rifle.There are many like it, but this one is mine"


    ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


    Sharpen it like you love it, use it like you hate it.

  • TBLondon is @tom

    Cheers Stew, I thought he was on here under another handle.







    "This is my rifle.There are many like it, but this one is mine"


    ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


    Sharpen it like you love it, use it like you hate it.

  • I had to look up those Global Ni knives as i was unfamiliar with these, but it turns out they seem to use the same Chromova 18 steel (which is just AUS6 with a good hardening)
    Quite a lot of Chefs in my region use the standard Global models in that steel (mainly G1, G2 G3, G10 models and various others), and the ones i get in for sharpening mostly receive a slightly convex edge in the 25 to 30 degrees inclusive region (depends on the specific needs/wants of the user) with a rather coarse finish (230 grit diamond powder + wax on a Rubber Wheel, then deburred with a Paper Wheel coated with 0.25 micron diamond compound)
    Now diamond is definitely not necessary on AUS6, but for me it works fast and also very clean (meaning very little burring which is also easily removed)
    The end result is a toothy edge that lasts surprisingly long for the Chef & can be touched up by him several times on a ceramic rod before he brings it back to me for a new edge. (about every 3-4 months)


    Since all sharpening i do is feedback based i've learned that too refined edges on Global knives don't last very long, at least not in a professional setting when used on those colored plastic cutting boards almost every restaurant uses nowadays because of food regulations.
    In general these boards are very abrasive on knife edges, and especially steel types without many wear resistant carbides like AUS6 will blunt quite fast.


    A good quality end grain wooden cutting board is much more gentle on refined edges so you can experiment to your hearts content with fine abrasives, but personally i would just leave a rather coarse edge finish on AUS6.
    For home use you could do very well finishing with just the medium ceramic stones on a Spyderco Sharpmaker or comparable.

  • A loaded strop will keep them going between sharpenings but give a smooth edge


    A ceramic hone will keep them going between sharpenings but give a coarser edge. Depending on the aggressiveness of the hone you can create a frown in the edge, and it will need the edge resetting on the stones more regularly.


    If you're competent on the stones, I'd reset the edge all the way from 400-6k and then maintain on the 6k and strop. Resetting the edge all the way means you're more likely to hit the apex on the 6k, rather than just the shoulders of the bevel.

  • I wouldn't put my global on a steel. If your going to use the ceramic honing rod then you need to be very good at honing the right angle or you'll do more harm then good. I use a wicked edge to establish a good edge and keep a DMT Diafold fine/extra fine, in the kitchen and just use that as a hone instead.


    I agree with the angles on Globals that @kwakster mentions. I've taken mine down to 20 inclusive and it wasn't good, loads of chipping. I actually have a main bevel of 20 inclusive with a 32 inclusive microbevel. Gives a sort of convex quality to it and better edge stability.


    In a professional kitchen I don't think you need a strop personally, I don't think you even need to go to 6k. I would often just go to 1k water stone for regular kitchen duty.

  • Dan Global double bevel knives have a wide thinning bevel around 10 degrees or less with an edge bevel around 15 degrees the thinning bevel been wide 3mm roughly can be done on a sub 1K grit I put an intermediate bevel1K a couple of degrees higher then a micro edge bevel 10K all done free hand .The image below is a Global thinning bevel is 3mm wide intermediate is around 1.5mm & micro bevel is around 0.1-0.2mm wide around 15 degrees. Hone on a stone on the micro bevel. A polished edge last longer but higher grits are slower to use so if you are not accurate enough the chances are you will remove the edge. I test my edge with the tree finger test(Murray Carter) and slicing through lightly rolled kitchen paper it should cut with very little pressure although this level of sharpness will not last it should stay reasonable sharp for a professional kitchen. The steel is reasonable but by no means brilliant as compared with VG10 or Blue or White paper Hitachi steel. The main thing with any chefs knife is that it needs to be thin behind the edge otherwise it is an expensive stick with a handle on it.

  • So do I need to sharpen these knives at 15 degrees and then finish with a finer grit at 10 degrees?


    So if I'm honing with a ceramic, strop or stone do I just hone at 10 degrees before each use?


    If you watch the global sharpening videos the guy just uses the guid rail and sharpens at the same angle, he doesn't change the angle after.

  • Firstly check the condition of your edge - does it reflect light? How much of the edge is missing an apex -where it reflects light it has no apex it is flat.
    If this is the case ~i will normally get an apex back since this can sometimes result in it been thick behind the edge.
    This should be done at around 15˚(it can be done with a sub 1K since this can be refined more later.
    Next drop your angle to 10˚ or less and use your coarsest stone say 400 grit or lower if you have it now aim together bevel about 3mm wide it need not remove all the edge bevel but you want to aim to slim the edge bevel to about 1mm wide at most. You may well scratch above the desired thinning bevel you can sand any scratches out with a 400 grit or courser wet & dry paper work perpendicular to the spine parallel with the machining marks from manufacture.
    If you are to sharpen effectively you will put scratches where you don't want them - if you are timid about this and only do the edge bevel the blade will get thicker & it will no longer cut properly since the shoulders of the bevel will stick on what you are cutting - the transition from the edge to the main blade should be pretty smooth if you can feel a line it is too thick.


    In answer to your question about the guide rail this will not help you sharpen the tip nor will it allow you to thin the knife the Global sharpening video just gives you enough to start with but to master freehand sharpening you will have to leave your comfort zone.


    I sharpen around 250 knives a month & I am constantly learning & refining my method there is no limit to how good you can get.


    Another rotor is to use tools like an Edge Pro but this sort of sharpening is very dull since so much time is spent setting angles.
    Often it is desirable for the edge bevel to be made more obtuse towards the heel for more heavy work this is easily done freehand but becomes a technical nightmare with controlled angle systems .


    In the end it depends on the range of knives you wish to sharpen but with freehand if you can get a blade onto the stone then you can sharpen it.


    If you had your Global from new you can see the thinning bevel if you cannot remember what it looked like go to a store and look at a new one.