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Sharpening a MAC with Minosharp 15* Guide Rails

post #1 of 13
Thread Starter 

Hello all!

 

First post here. I'm having trouble getting my MAC MT80 back to factory sharpness. I purchased it 2 years ago when I started to apprentice in the kitchen a bit while I was a waiter. I had it sharpened at Korin in New York where I also picked up a 1000/6000 combination stone and fixer. After 5 months my "apprenticeship" was over and the knife went back home for occasional home cooking. 

 

I now started full time in the kitchen again and had the knife sent to MAC in California for a nice resharpening and to fix a broken tip. It came back sharp but definitely not like the factory edge it had. It cannot hold sharpness down the whole length of the blade, and it loses the edge quite fast, even with frequent honing.

 

I decided to purchase the Minosharp 15* guide rails that you stick on to the spine of the knife to hold a consistent angle when on the stone. They worked the first few times on the stone but I am back to the same issue...Can't hold the edge and can't get it razor sharp down the whole length. 

 

 

What am I doing wrong??

post #2 of 13

As a sort of general proposition, guide rails suck for any knife with more than minimal rocker, and/or belly, and/or that's 8" or longer. 

 

As to the rest of your sharpening, since I don't know what you're doing I won't comment other than to say if you don't know how and why to deburr, how and why to soak and flatten, etc., etc., etc., you may want to delve into the whole sharpening subject more deeply.   

 

Since I don't know what MAC USA did to resharpen your knife and won't comment other than to say they usually get high marks.

 

My suggestion is to decide whether you want to learn to actually freehand your knife or to buy some sort of gag or tool and jig to help you sharpen.  The Minosharp3 at about $80 works well enough to keep my daughter happy with her MAC Pro MBK 95 and may be good enough for you.

 

BDL

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post #3 of 13
Thread Starter 

Thanks for your response.

 

As for some more details, I soak the stone 10-15 minutes, or at least until bubbles stop. I flatten it each time, either before or after use, soaking the fixer as well. 

 

I've also used the fiskars/mac rollsharp in the past and it sharpens well, but not factory edge splitting hairs and newspaper. 

 

I've seen so many videos and gone to Korin's sharpening demos so many times that I've gotten bored/frustrated. I think the issue has more to do with what you hinted at regarding the burr. Perhaps I'm not raising a burr adequately/properly, partly because I'm not really sure when it's even been raised. That might be the problem. How can I detect when it's there? If put on a grinding wheel, the thing comes up immediately (I've seen it at Korin) and it's noticeable and huge. But on a #1000 stone, it's not that visible. 

post #4 of 13

I have used the Fiskars with great results for the past ten (10) years, really want to try the MinoSharp three stone though.

 

It surprises me that Harold at MAC USA would let something go out not razor sharp, I've always had great service.
 

Chef,
Specialties: MasterCook/RecipeFox; Culinary logistics; Personal Chef; Small restaurant owner; Caterer
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Chef,
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post #5 of 13

I don't want to get into the science of "bending burrs" and "deposit burrs," or even if there's a difference between the two. 

 

When you sharpen, you almost always create a wire, and the wire almost always bends and/or develops a deposit bead on the side not being sharpened.  The easiest way to feel it is to turn the knife edge up, then push your thumbnail gently up the face of the knife which was not being sharpened.  If you feel your nail grabbed even slightly as though running into a "hook," that's the burr.

 

Proper sharpening -- okay, sharpening the way I do it -- involves creating a burr than chasing it by getting it to move from one side of the edge to the other (called chasing).  When you can get it to do that with every stroke, your knife is ready to be deburred. 

 

If that makes sense, we can move on to the next level of refinement.

 

BDL 

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post #6 of 13

mmm... I don't have a lot of experience sharpening and when I started I bought the very same minosharp guiderails you mention.

Not only that, but I also bought another cheapo one set at a more teutonic angle of 20* - the idea at the time was to put a final microbevel... silly me...

The minosharp thingy will give you an angle which is best described as "between 10* and 15*", the reason being that there's other stuff involved, notably the blade's width.

I would tend to agree with BDL (who gave me quite a few excellent advices in other posts, along with JBroida) that at the end of the game real freehand is the way to go but I'd say that those guiderails had helped me the very first times to get a feel of what ~12* really meant with wrist positioning and to start building that into muscle memory.

Remember to clip the guiderail at an angle so that the longer side is as parallel as possible to the actual edge, not the spine of the knife and to position it rather towards the tip than the heel.

BTW, dunno if this applies to you but I've had pleasant surprises from using the magic marker trick, as suggested by various experts in this and other forums.

post #7 of 13

also, i've found it immensely helpful when teaching others to be able to use an angle finding app (like a digital protractor or something like that).  Few people know what 10, 15, or 20 degrees look like.  My experience is that people either pick an angle MUCH lower than what they intend or MUCH higher.

post #8 of 13

+1 with Jon.

 

My usual advice is to get a protractor, some paper, and draw a three or four large 15* (or whatever) angles and put them -- flat and standing up -- around your sharpening station so you can look at them and compare your knife angle on the stone while you sharpen. 

 

If you can get hold of an electric protractor as well to help you picture what the knife should look like, so much the better.  Some guys put their stone in an articulated vise at the desired angle, and try to hold the knife horizontal as they sharpen.  Personally, I think that's weird but to each his own.

 

In your case, it appears you're already used to "clicking in" and letting the old angle on the knife control the new angle.  That's fine for ordinary sharpening but is also part of the process which results in inevitable thickening and NO GOOD for thinning.  So... if you do "click in" (whether consciously or unconsciously) part of the thinning process is going to be making sure you don't do it when you profile.

 

The Magic Marker Trick will help you a lot.  If you're taking ink off the edge within a couple of strokes, you're too obtuse.  If you take ink off the face of the knife way over the bevel, you're too acute. 

 

The Magic Marker Trick will help you with so much more, please use it.

 

BDL

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post #9 of 13
Thread Starter 

So after some more research on "chasing burrs" and with your advice on how to feel for the burr, I was able to raise a burr on both sides of the knife, tip to bottom, on both the 1000 and 6000 stones. I also put some sharpie across the bevel, which at this point is about 1-2mm thick, and that helped with sharpening the tip. I deburred with a few diagonal light strokes on the stone and on a couple of corks. Then stropped on whatever I could find (in this case a cardboard box). 

 

It's shaving hairs easily off my arm and is able to slice through paper from within any point on the knife's edge. 

 

Thanks for your advice! However, I'd like to hear about some advanced techniques for the future to keep it going sharp. This knife has been through a lot (tip repair, grinding wheel at Korin, the guide rails), so I'm not sure if too much metal has been taken off already. Your comments about the clicking in and thinning are something I'd like to hear more about for the future, because at the moment I definitely "click in."

post #10 of 13

Wow, how do you manage to get a burr on the 6000?!

Every time I move to that stone and switch to a "stropping" motion, the burr melts away at the very first passes and after that there's no way of reforming one (not that I really want or need to).

Maybe I should apply some more vertical force. But does it make sense to reform a burr on a 6000 after it's gone?

post #11 of 13
Thread Starter 

As to your second question, I don't know if it makes sense to re-burr on a finishing stone. Mind you, the burr was extremely small, but I could definitely feel something there that was gone when I deburred. I picked up the technique off of Japanese Knife Imports or one of those similar sites.

 

As to the first question, I use pressure on the upstroke and very light to no pressure on the downstroke.

post #12 of 13
Quote:
Originally Posted by Rumenta View Post

Wow, how do you manage to get a burr on the 6000?!

Every time I move to that stone and switch to a "stropping" motion, the burr melts away at the very first passes and after that there's no way of reforming one (not that I really want or need to).

Maybe I should apply some more vertical force. But does it make sense to reform a burr on a 6000 after it's gone?

As to making burrs on high grit stones, its very possible and not that hard... even with a stropping motion.

 

Anyways, on to the necessity of burrs... make it once (on whatever your coarsest stone is that you plan on using that day).  Everything else is just refinement, cleanup, and burr removal.  That doesnt mean however, that you wont be forming or be able to feel a burr on your higher grit stones.  Just make sure its gone when you're done.

post #13 of 13

Thanks guys, I'm gonna give this 6k re-burring a try soon. (I just have to do a friend's knife, completely covered in rust and badly chipped edge: great chance to practice!)
 

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