I just bought a belt sander, and I figured that since I hate sharpening knives, I might take a stab at sharpening them up on the sander. My question is, what is the minimum grit paper I need to get a decent edge? I'm looking for something practical, I'm not looking to be able to shave with the knife.
Sharpening question
- Thread starter ChaoSS
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7X57chilmau
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I'd probably use a #400 for general work... With a light touch, that should be pretty shavey.... It'll cut DAMNED quick too, so use that light touch...
J
J
Ok, now another stupid question...
I also have an orbital sander, and while I don't have a 400 grit belt lying around, I do have 400 grit paper lying around, would that work, or would trying to sharpen something on an orbital sander just make a mess of things?
I also have an orbital sander, and while I don't have a 400 grit belt lying around, I do have 400 grit paper lying around, would that work, or would trying to sharpen something on an orbital sander just make a mess of things?
Others may advocate using a belt sander to sharpen with, but I advise anyone without a ton of experience with these things to stick with manual.
OTOH, you'll want a 600 grit belt on your belt sander (sorry, but I'd rather he use the finer grit and avoid the "Hey! Where'd my blade go?")
A palm sander is one of the tools one of our professional knifemakers "discovered" a few years ago and I use it with progressively finer paper as if it were a vibratory "stone". Take the pad off so you're on the metal platen (or glue a flat glass plate to it) and clamp it face up in a vice and you can do amazing things.
OTOH, you'll want a 600 grit belt on your belt sander (sorry, but I'd rather he use the finer grit and avoid the "Hey! Where'd my blade go?")
A palm sander is one of the tools one of our professional knifemakers "discovered" a few years ago and I use it with progressively finer paper as if it were a vibratory "stone". Take the pad off so you're on the metal platen (or glue a flat glass plate to it) and clamp it face up in a vice and you can do amazing things.
Can you get a 600 grit belt at, say, Lowe's? Or do I have to go online to get that? I haven't been down there yet, I just got the belt sander yesterday at harbor freight and I didn't see any belts fine that 120 grit, but considering that I can get up to 400 grit paper at Lowe's, I'm holding out hope that I can get the belts too. (Might just be a fool's hope, we'll see.)
I kind of figured it would sand really quickly, so I was planning on starting with an old rusty knife that I don't care if I destroy, maybe see if I can find that old rusty machete to start with. The palm sander works a lot slower than the belt sander, so would the 400 grit paper be reasonable on there?
I can get a reasonable edge with stones, and I don't even have nice ones, I just don't like to work that way because I'm really not the greatest at holding a consistent angle between different stones. I'm not terrible, just takes a bit of concentration and it's kind of a PITA for me. I kind of figured this might be the shortcut that would make it easier, other than putting down the money for a system that hold the knife at the right angle.
On that note, are there any videos that show how those systems work, I've always wondered how they worked, since the knife doesn't have just one straight edge, they always have curves in them that require moving the knife.
I kind of figured it would sand really quickly, so I was planning on starting with an old rusty knife that I don't care if I destroy, maybe see if I can find that old rusty machete to start with. The palm sander works a lot slower than the belt sander, so would the 400 grit paper be reasonable on there?
I can get a reasonable edge with stones, and I don't even have nice ones, I just don't like to work that way because I'm really not the greatest at holding a consistent angle between different stones. I'm not terrible, just takes a bit of concentration and it's kind of a PITA for me. I kind of figured this might be the shortcut that would make it easier, other than putting down the money for a system that hold the knife at the right angle.
On that note, are there any videos that show how those systems work, I've always wondered how they worked, since the knife doesn't have just one straight edge, they always have curves in them that require moving the knife.
villemur
Member
There are a bunch of videos on Youtube showing people sharpening knives on a belt sander. I even bought some fine grit cork belts to try it myself. After trying it a few times myself I think it's a good way to ruin good knives if you don't know what you're doing. It takes off too much metal too fast. And if you're not careful you can build up heat and mess up the temper of your blades. And if you're really not carefull you can catch the blade and really hurt yourself.
Now I use the belt sander for lawnmower blades and machetes, and I sharpen my good knives by hand. I'm not saying that it can't be done, but it's harden than most people realize.
Now I use the belt sander for lawnmower blades and machetes, and I sharpen my good knives by hand. I'm not saying that it can't be done, but it's harden than most people realize.
ArfinGreebly
Moderator Emeritus
In The Same Sentence
You know, I'd normally refrain from using the words belt sander, sharpening, and stab all in the same sentence.
It almost sounds like an invitation to stitches.
You know, I'd normally refrain from using the words belt sander, sharpening, and stab all in the same sentence.
It almost sounds like an invitation to stitches.
AG,
That's exactly the combination that comes to mind when I read/hear "belt sander" and "sharpen" and that's exactly why I never recommend combining the two.
That's exactly the combination that comes to mind when I read/hear "belt sander" and "sharpen" and that's exactly why I never recommend combining the two.
In other words, you don't want to hear about my idea to introduce a blind fold and make it a drinking game.
In all seriousness, I bought the thing for work with wood, and I want a fine grit belt for that, so I might as well try it with a crappy knife, carefully, and see what happens. And I'll have to try the palm sander as well, if you say that works, I was half thinking it might work and half thinking it would just make a mess of things with the less even motion.
Now it's just an issue of finding a 400 grit belt, hopefully Lowe's or Home Depot comes through on that score.
In all seriousness, I bought the thing for work with wood, and I want a fine grit belt for that, so I might as well try it with a crappy knife, carefully, and see what happens. And I'll have to try the palm sander as well, if you say that works, I was half thinking it might work and half thinking it would just make a mess of things with the less even motion.
Now it's just an issue of finding a 400 grit belt, hopefully Lowe's or Home Depot comes through on that score.
7X57chilmau
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When finishing my last dagger, the polishing buff caught and tossed the finished blade blank on me.... A minor scratch for me (luckily wearing leather), and the blade's temper proven..... Gotta be careful with machines that store rotational energy!
For the record, I do all my sharpening by hand. I don't own my own belt sander (yet).
J
For the record, I do all my sharpening by hand. I don't own my own belt sander (yet).
J
Oh, yeah, that reminds me of my other question, if I use a belt sander, which way do I go? Does the edge go with the direction of the belt or against it? I know when sharpening blades I push the blade against the stone rather than pull, but it seems like with a light tough, going in the "pulling" direction, it would still work fine, and if I lose the knife, it's getting tossed away from me instead of at me.
DAVIDSDIVAD
member
Check ebay for decent prices on the finer grit sanding belts.
Just be sure that you're buying the correct dimensions.
Just be sure that you're buying the correct dimensions.
villemur
Member
Sharpen the opposite of the way that you would by hand - have the edge pointing in the direction of the belt's rotation. You do not want the sharp edge cutting into the belt and you don't want the belt catching the sharp edge and throwing it.
Make sure the belt is moving "down" or "away" and that the edge is facing "down" or "away" so that when it yanks it out of your hands it moves away from your pink bits.
Nasty story from a shop in IL where the knife was yanked out of the hands of an experienced operator. It smacked into the wall and rebounded towards him smacking him hard in the gut. He didn't know which end hit him until he realized wet sticky stuff was running down his abdomen. The trip to the ER revealed the point had smacked him in the gun and had penetrated nearly to the intestines only to rebound out of the wound and continue on it's pinball path. Probably rotating furiously when it hit otherwise it would have stayed in place.
Nasty story from a shop in IL where the knife was yanked out of the hands of an experienced operator. It smacked into the wall and rebounded towards him smacking him hard in the gut. He didn't know which end hit him until he realized wet sticky stuff was running down his abdomen. The trip to the ER revealed the point had smacked him in the gun and had penetrated nearly to the intestines only to rebound out of the wound and continue on it's pinball path. Probably rotating furiously when it hit otherwise it would have stayed in place.
That's not pretty.
I don't have a shop so this will be happening outside. I guess if something got thrown hard enough it could hit my truck, but that's far enough away that I can't imagine anything like that happening.
I'll be careful though, I've learned enough lessons the hard way with power tools to be interested in learning them all that way.
I don't have a shop so this will be happening outside. I guess if something got thrown hard enough it could hit my truck, but that's far enough away that I can't imagine anything like that happening.
I'll be careful though, I've learned enough lessons the hard way with power tools to be interested in learning them all that way.
Zeke/PA
Member
I use a belt sander often for sharpening a myriad of stuff from mower blades to knives to axes.
I have a smaller belt sander also , used mainly for knife blades.
I don't use the "down and away" but hold the cutting edge "up" for better control.
A Buffing Wheel??
Now that's something else again!
I have a smaller belt sander also , used mainly for knife blades.
I don't use the "down and away" but hold the cutting edge "up" for better control.
A Buffing Wheel??
Now that's something else again!
7X57chilmau
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On a fixed stone, I both pull or push the edge on the stone, depending on what I'm trying to do.
When I'm establishing a grind angle, I actually go in circles, never removing the blade from the stone. Removes material faster.
When I'm about there, the last few strokes on a grit that will be superseded by a finer grit are pulling strokes, which will cause the burr to raise more visibly... And more quickly.
The final few strokes on the final stone are pull strokes, followed by a couple very light pushing strokes (as if trying to cut a sliver from the stone) to shear off the final burr, which is all but microscopic on a decently fine stone.
A strop is always a pull stroke, to avoid cutting the leather.
Just my way... Gotta find what works.
J
When I'm establishing a grind angle, I actually go in circles, never removing the blade from the stone. Removes material faster.
When I'm about there, the last few strokes on a grit that will be superseded by a finer grit are pulling strokes, which will cause the burr to raise more visibly... And more quickly.
The final few strokes on the final stone are pull strokes, followed by a couple very light pushing strokes (as if trying to cut a sliver from the stone) to shear off the final burr, which is all but microscopic on a decently fine stone.
A strop is always a pull stroke, to avoid cutting the leather.
Just my way... Gotta find what works.
J
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