Sharpening a global?

[Benuser]

Do you perchance have an fairly accurate idea of how many thousandths you would thin to, before applying such a mini-bevel? I'd be interested in having a something to aim for next time, instead of just settling on something rather arbitrarily -- it wouldn't even much bother me if you yourself had settled on your thinness quite arbitrarily; I'm just looking to follow a bit of a recipe next time, I think.

After said thinning I probably put my standard edge on it, right side convex ending at some 12 degrees, left side straight somewhere around 18 to compensate for steering. After that, cutting the micro-bevel, so that the thin geometry of the fine edge is maintained.

 

[Knife2meatu]

Very interesting indeed!

Cheers

 

[Cmfuen]

I have sent two family members to the emergency room by sharpening their knives.

I am now going to steepen the edge of my mother’s favorite Kikuichi utility knife she insists on using for way too many tasks!

 

[Dhoff]

Any good instructional videos on how to thin a knife out there?

 

[Benuser]

 

[Benuser]

Start by removing the shoulder, where bevel and face meet. Next step is sharpening at the lowest angle you're comfortable with, thus creating a relief bevel. Verify your progression by looking at the scratch pattern, or use the marker trick.
Further thinning implies pressing on the opposite side. See Mr Broida's videos.

 

[HRC_64]

when you take out the shoulder, just take care to not make a dead-flat in the grind cross section

 

[Benuser]

Easing the shoulders will take a few strokes only.

 

[Dhoff]

Thank you both. What grit would you recommend?

 

[Benuser]

My pleasure. For the shoulders any grit should do, 1k or lower. For further thinning take the coarsest you have. I use a 220 Shapton GS, followed by a Chosera 400.
Or use automotive sandpaper on linen, like Robert Bosch 'Metall', P120 to start with. Use hard rubber or soft wood as a backing. Only edge trailing. Stay away from the very edge or you may cause an overgrind.

 

[Bert2368]

I was at loose ends at GF's, decided that the performance of her 17 year old set of Globals was just too unpleasing, I had to do SOMETHING.

Found a new, unused 6" X 2" soft Arkansas stone in her kitchen drawer, and some rubber mesh scraps left over from lining the kitchen cabinets And a tube of metal polish. Stole a couple of sheets of copier paper out of the printer and letter folded them to be 3 layers thick. Annointed one with metal polish, left the other bare.

I used a few drops of water on the soft Arkansas and went at it, edge forward. Feedback was useable, started to get a little "sandy" feeling if angle got too steep, skated with little resistance if too shallow. I'd judge that it cut and left a surface like it was somewhere between my 500 and 1,000 grit man made water stones.

Then cleaned, stropped a few strokes on the metal polish bearing paper, cleaned again and stropped a few more times on the bare paper. DONE.

They're about as sharp now as they ever were. Any of them will happily cut a thin, straight 11" slice off of a loosely held piece of copier paper, they all shave arm hairs, but not super comfortably.

To test the chef's knife, I thinly sliced a pound of venison steaks and quickly sauteed it in a smoking hot pan with butter & olive oil , dusted with a bit of paprika, granulated garlic, black pepper and salt.

Sprinkled the seared but still pink in center venison steak bits with toasted sessame seeds, added a dab of "S&B premium" prepared Wasabi. GF approves of this snack...

When life gives you dull globals and no J nats or leather strop, make lemonade.

 

[Benuser]

Great write-up! Not that far from what I once proposed with Krupp's 4116 in the case of the common Victorinox, where the grain is larger than with Zwilling and Wüsthof: 400 Chosera — my coarsest one in those days, enough pressure, cleaning up and deburring by stropping on the green abrasive side of a Scotch household sponge. Done.
Problem is likely to be the same: big carbides and clogging of them in far too soft a matrix to hold them, resulting in edge instability at any angle.
Thanks, Bert!

 

[DanielCoffey]

For 17-yo Globals they are in pretty good condition. I am very impressed at your ingenuity!

Some of mine have lost metal near the heel due to my poor use of a MinoSharp. I have just got a set of King stones in 220/1000/6000 and will be looking at remedial work on them soon.

Any thoughts on how badly I have mangled my GS-5 and GSF-15?

 

[Bert2368]

For 17-yo Globals they are in pretty good condition. I am very impressed at your ingenuity!

Some of mine have lost metal near the heel due to my poor use of a MinoSharp. I have just got a set of King stones in 220/1000/6000 and will be looking at remedial work on them soon.

Any thoughts on how badly I have mangled my GS-5 and GSF-15?

Hopefully you got a 400 mesh diamond plate to maintain the water stones?

If so, start working the heel of the GSF-5 back into a smooth curve, eliminating that "reverse belly".

If not, you COULD use the 220 waterstone, but you'll probably dish or groove it with that kind of a major repair. Maybe start with 160 or 200 wet/dry sandpaper on a piece of glass?

Or a WATER COOLED low speed grinder, if you have access?

Once the edge is reshaped to a nice, smooth, convex curve and the bevel along it is somewhat uniformed, proceed to the 1000 grit water stone, sharpen normally. Then strop, with or without compound, it will improve the edge a bit either way.

I wouldn't even bother with the 6,000, I tried a 5,000 on these knives and it made the edge smooth feeling, it sort of shaved hair a LITTLE better than what I just did with the soft Arkansas/paper & polish.

But the finer stone's edge worked less well on meat or tomatoes, GF said I had made them "duller", she meant the edge was less toothy/grabby.

That poor little GF-15!

If you don't mind spending a LOT of time and shortening it a good bit, you could do much the same to return the edge to properly convex or at least straight.

I personally would do the primary reshape of the pareing knife on a medium grit stationary belt sander, slowly in very small steps to avoid overheating.

I would dip it in water to cool as soon as any heating was detected. Once the edge was in correct profile and the bevel roughly re-established, same 1,000 grit and stropping as the larger knife.

 

[Benuser]

I prefer a soft backing when using sandpaper, hard rubber or soft wood, to avoid facetting and have a smooth, convexed face.

 

[vicv]

I've never sharpened a global. Are they any different than a wustoff or henkels as sharpening difficulty? Because those knives are relatively easy. Not as easy as carbon but not bad. Just use the right equipment and don't start at 1000 grit. Start at around 200. Should take less than 5 minutes from very dull. I usually don't bother with Waterstones for these. I just use a crystolon. Or if I'm honest a belt sander to do the thinning then a crystolon fine to finish the edge

 

[mhpr262]

The knife sailed through the pepper, her skin, fat/muscle layers and then cut the flexor tendons of her left index and middle fingers before stopping on bone.

Good god I cringed reading that.

 

[rick alen]

A micro-bevel should provide everything a convex edge does. You can even convex the micro-bevel if you want. But thinning the edge down to .015"/.4mm, or a little less even, is going to make everything easier. And microbevel I find is the best way to remove the last remnants of a burr. Just strop it in on a clean stone. That is especially important when dealing with gummy-acting steels that easily pull a wire, you don't want loose grit.

 

[zitangy]

I've never sharpened a global. Are they any different than a wustoff or henkels as sharpening difficulty? Because those knives are relatively easy. Not as easy as carbon but not bad. Just use the right equipment and don't start at 1000 grit. Start at around 200. Should take less than 5 minutes from very dull. I usually don't bother with Waterstones for these. I just use a crystolon. Or if I'm honest a belt sander to do the thinning then a crystolon fine to finish the edge

Just my experi3nce....i avoid going below 400grit for globals for the reason that if the striations are too deep with the 200 grit, i wld get just 1 tiny " micro chip" alomg the edge when i am done polishing.

double sure that i dont see it at 1000 grit

 

[HRC_64]

wet dry 3m paper #400 on a soft backing
... saves time and hassle and is cheap

 

[vicv]

I've never had that before happened. I do use quite light pressure though at the end

 

[vicv]

wet dry 3m paper #400 on a soft backing
... saves time and hassle and is cheap

I've never tried to soft backing like that before. But I've always found that paper wears out much too quickly. And I dislike doing trailing only Strokes

 

[HRC_64]

I've never tried to soft backing like that before. But I've always found that paper wears out much too quickly.

The soft backing avoids pressure points, whereas
if you sharpen a high-angle convex ege on flat stone you will wreck it,

unless you are very, very good...but in my experience
the global steel will facet on fast, hard stones

The paper will last longer on a soft backing
because the lack of pressure points, also.

TLDR...globals aren't worth buying new stones,
and 3m papers work well and are cheap.

 

[vicv]

Fair. I use stones to sharpen my softer stainless knives . Usually oil stones. Or just a quick trip to the belt sander. Then I deburr on a paper wheel

 

[rick alen]

Interesting that Globals are just made from a totally 'nother kind of steel. I hope to never actually have to sharpen one.

 

[Cyrilix]

Start by removing the shoulder, where bevel and face meet. Next step is sharpening at the lowest angle you're comfortable with, thus creating a relief bevel. Verify your progression by looking at the scratch pattern, or use the marker trick.
Further thinning implies pressing on the opposite side. See Mr Broida's videos.

Is there any reason to not just flatten out the primary bevel dead flat until thin enough and then work on re-convexing? Then lastly, redo the edge (secondary bevel).

 

[Benuser]

Is there any reason to not just flatten out the primary bevel dead flat until thin enough and then work on re-convexing? Then lastly, redo the edge (secondary bevel).

If you're familiar with the thinning process that is very well possible. In this case though I suggested to proceed by small steps.

 

[HRC_64]

Is there any reason to not just flatten out the primary bevel dead flat until thin enough and then work on re-convexing? Then lastly, redo the edge (secondary bevel).

The other issue (IMHO) with global is they don't have any shape in the gind...
all the convexity is on the edge, so if you lose it there,
you are killing the knife's personality and how it cuts.

It doesn't have the harder, higher quality type steel to take super-steep and thing
edges, its just not how the knife is designed...it will be sharper but won't cut better
if that makes any sense (paper cuts vs food cuts, etc).

YMMV but that was my experience with it...more work, worse performance.

 

[ModRQC]

A most revealing thread. Thanks to all, I now know the knife I just bought is skilled sharpeners' worse nightmare. I'm glad I didn't read that before buying... most discouraging! At the price I got it though, I still think it will serve me well, and fulfill its meaning - which is to get to know what I want, and what I don't want ever again. All I've ever handled are 30$ knives, I had to start somewhere. Learning to sharpen with the worse ever knife or so will make it worthwhile in the end when I'll come by easier blades. Will most probably destroy the G2 with ill sharpening along the way though lol. That should speed up the need to buy a decent edge, so I guess it wouldn't be that bad an outcome.

 

[kayman67]

Reading this, I wonder how the heck I could sharpen them just fine.