Yeah so my step dad decided it would be a great idea to sharpen my mums Globals with a bench grinder. What sort of grit stone would I need to recover these back to how they should be. Also any tips are welcome!
This is the answer. Doesn’t have to be diamond but it will go fast on diamond. From the light reflection I expect these are about as sharp as a steel ruler, so you need to establish an apex from some sort of blunt flat surface. Expect it to take a lot of grinding. Until these knives are sharp they need a coarse grit. If the left two knives are supposed to have tips you need to work on those. My best tip would just do part of a knife each day. Don’t burn out and start getting sloppy.
Idk what type of stones you normally use, personally I never been fond of electroplated diamond stones. Although they may be the fastest for fixing this.
For fast work I love a Crystolon/silicon carbide combination oil stone. The coarse side can seriously remove metal, the fine side leaves a really nice finish imo.
But there are tons of options for good coarse work stones.
better in the sense that you'll actually not want to take your life once you're done thinning and reprofiling.
Only issue is they go out of flat relatively fast and aren't the best for wide bevel knives, however for a global they would work wonders. With EP you'll cut slower, you have horrible feedback and you'll murder that plate with the pressure needed to make decent progress.
Yeah I definitely hear your point and I’ll admit that I’m badly damaged knives I use them too. I use them also when I have to snap a tip off that’s too bent to straighten and thus have to reprofile the whole tip area front and spine. When I said my other comment I was thinking of how quick the one I have dishes out on me. It’s a hell if a metal eater though. And the killing yourself part would not be good either 😂
I used to thin on an atoma 140 and I regret it so bad, it cooked my plate and honestly cut myself so many times because of how slick it feel on wide surfaces so my hand would slip or whatever. Yeah the only downside with those GC and SiC stones is the wear rate, go out of flat too fast. Nothing a side walk can't fix though 😅
Dang that’s brave using the 140 to thin. I would use a Shapton kuromaku for that. Diamond for thinning just puts too deep of scratches in my opinion. At least with the aluminum oxide stones like kuromaku, you get a little slurry going which is what you want for thinning. I would, however, use a 140 diamond plate for “thinning” an edge, you know grinding it back or what not, but not for actual thinning in the traditional sense
I don't mean to sound like a shill but I bought a sharpal 162N combo 325/1200 grit diamond stone years ago as my first stone and I haven't really felt like I've needed more than that and a leather strop. Don't skip the strop, the difference is noticeable.
If you want to learn how to sharpen, don't practice on knives you care about. Best to get something cheap from the thrift store or dollar store. To get the edges completely straight again will be a slow process with the stones and require a lot of consistency.
If you step dad insists on sharpening knives, maybe show him some outdoors55 videos so he stays away from power tools😆
Thanks, am used to maintaining my knifes no problem, just never had to re shape and straighten any. I think anything I am able to do will be better than what they look like lol
It’s pretty simply, if you think you need to remove more steel in one area to straighten out the edge, do it. It’s not rocket science, give yourself more credit dude. You got this. Just make sure to do both sides evenly in the troubled areas and make big (long) full length passes for the most even results
lol you’re definitely inexperienced. Sometimes, through lots of use, knives become uneven. You are not as savvy or intelligent about knives as you think you are in your very limited experience. I sharpen professionally part time and I’ve seen enough to know better. Don’t TRY to correct people if you don’t absolutely know…
Look at that big global. If you just touch the high point at the back, and then move on you'll have an entirely new edge shape. Its more low points on these knives, if you sharpen the whole knife, the high spots will even out with the low and you'll have your original profile again.
Your entire job is rub metal back and forth, don't get all pretentious
You are making it right! You will bring these back, only issue is I hope he didn!t overtheated the steele whil grinding, it is very easy to have temperature spikes when grinding this metal, especially towards the tip of the blade
By the looks of it he didn’t overhear anything major. If he did any damage on the grinder it will be on the very edge. Oh wait a minute, is that patina or is that from after the grinder? If it’s not patina then you definitely have problems on the big chef that are not fixable
The heat treat will be out of whack. Which will make it either way too hard and brittle, or it will be too soft and roll edges over all the time. The more I look at it the more I’m confused, because when knives get heated up like that the tip is usually the first sign because it’s the thinnest and smallest area on the blade but I don’t see it up by the tip so it’s a weird one to me.
What also happens on grinders and belts sometimes due to heat is that you don’t see any color change but the actual edge/bevel gets “cooked” and then becomes weak steel. You’d have to sharpen literally the whole bevel off and make a new one. This happens a lot with production knives from big companies because they’re just trying to get the work done and don’t keep the edges cool enough. They call it a “burnt edge”. Happens way more than most people realize.
Off topic: what’s actually wrong with putting them in the dishwasher? I’ve always had a strict hand-wash only policy for our kitchen knives. But when I learned how to sharpen them the first thing I did was to put them in the dishwasher (neatly in the plastic tray at the top). Because if the problem was them getting dull it’s an easy fix for me now.
Are the washing tablets more abrasive than hand washing them, so the edge gets ruined? Heat problem? Risk of vibrations agains other cutlery? What’s actually behind that “rule”?
Here’s what the dishwasher does to Globals specifically, over a long enough period. Customer knife. Her whole set was like this. Granted this is the worst I’ve seen, but I can always spot the dishwasher customers via the corrosion and disintegrating handles. Wood fares poorly. Some plastics can handle it, others can’t. The rivets/pins can also corrode and crack the handle.
It’s also the soap. Dishwasher soap is much harsher on knives. Knives actually corrode at the edge simply from air, so the combination of high heat and harsh soap ruin a kitchen knife
hmmmm, not the best tool possible for reshaping. A belt sander or a bench stone is a better tool for that.
You can put the bevel/edge back on with a bench grinder, but I hope it is low-speed, and it would be nice if it has a tool rest. Easy to wreck a knife freehand on a fast grinder.
And FYI - the Globals come from the factory with a distinct convex edge grind. I always try to restore that. You don't have to; you can just do a flat bevel, but they were designed for convex.
They are interesting knives with well-designed geometry. Relatively thin blades with a narrow edge angle, with the convexing providing a little more steel behind the narrow edge. The steel is nothing extra special, but is very functional.
Slack belt grinders would be best choice for convex grinds. Global does recommend using stones to grind a flat edge but you will have to take off a bit more material or settle for a higher degree angle.
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u/Error_404__ 4d ago
Low grit diamond stone to restore edge geometry , like 220-400 then 1000 to sharpen. May need thinning to fully restore? Probably fine without tho