Recommendation? (sharpening) more pressure and less strokes or light pressure and more strokes?

more pressure and less strokes or light pressure and more strokes?

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I am in the lighter pressure category but, it just depends... Once I apex then I definitely lighten up the pressure to protect that thin edge of steel. When I am roughing I would say medium to light pressure to preserve the stone. Stone wear rate vs pressure seems to be a parabolic curve, a little too much pressure and the wear rate really increases. The idea of using more pressure to break down the stone so it doesn't glaze is totally foreign to me as a machinist. Use it properly and dress it when it needs it is what I think works best. Of course no hard and fast rules, it all depends on the steel and stones.
 
more pressure and less strokes or light pressure and more strokes?
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Neither and both.
For harder / higher alloy steel more firm strokes.
Still
though the final strokes on each stone are very light and on the final stones I don't apply much pressure even on the good stuff.
That said the contradiction to all that comes when sharpening the less hard wimpy steel. Firm force is a mistake with that and light strokes through out is best.
If I have to sharpen that stuff . . . at all . . . if I have to . . .
I guess.
Currently looking at buying another M4 blade at ~63 ;)
 
PS : I use the fewest strokes possible and part of what facilitates that is being assured the stone is right on the edge with each stroke by using a sharpening guide.
 
As said, it depends.
I use heavy pressure on silicon carbide stones to hog off metal, like for thinning and setting the bevel. As I reach the apex, lighten up drastically and switch to diamond.
For touch ups, it's diamond only and very light pressure.

So... silicon carbide reprofiling heavy pressure, diamond finishing light pressure.
This is the fastest way I know to get the results I want.
 
For initial grinding and/or shaping of the bevels...
... on SiC or AlOx wetted stones (oil or water), heavier pressure is OK.
... on plated diamond hones, moderate pressure is OK on a lubricated hone (water/oil), but won't work so well on a dry hone (clogs very fast). Avoid heavy pressure on a plated diamond hone, as it could be damaged.

For finishing and refining the edge, heavy pressure is NEVER a good thing. Keep it light, and even lighter the closer you get to finishing. Don't rush this part; let the stone very GENTLY get the work done.
 
Instead of pressing the blade down hard on the stone I use a coarser grit stone. If you do not have a coarser grit, it's going to take more strokes. There is no substitute for using the right tool for the job.
 
kwselke said:
Instead of pressing the blade down hard on the stone I use a coarser grit stone. If you do not have a coarser grit, it's going to take more strokes. There is no substitute for using the right tool for the job.
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I think the question is more nuanced than that. I take it as assuming you are using the right stone and asks how do you use it?

The same question is asked about how to use the grinding wheel on a bench grinder or surface grinder as well. In a way, it is very similar. Press a little harder to break down the wheel or not?
 
It all depends on what you're doing, the abrasive, the steel, and then unless you're using some kind of scale and can quantify the force, everyone will all have different definitions and perceptions of what light, medium, and heavy pressure actually constitutes. Most of the above comments are accurate, but you'll have to practice, experiment, and get a feel for things.
 
On knives used a lot, deli & meat market knives I take it to the coarsest stone I have, a 80 grit SiC and use plenty of pressure while setting
a new bevel and creating a burr. (We don't use knives here like they do.) Remove the burr and on to the fine to finish it off. If you don't use the
coarsest stone and pressure then you'll take more time getting the job done. DM
 
Depends on the conditions as others have stated, and there are many pressures between light and heavy.

Also, I think it’s important to consider yourself. Even when “heavy” pressure might work well, how long are you going to have to apply the pressure and for how many knives? Some people’s bodies (or techniques) do not tolerate prolonged periods of intense grinding. Versus will it take forever to grind the knife at a lighter pressure? Either way you may have to change up the pressures, the stones and/or take breaks. (Obviously too much pressure can ruin a job at a particular stage, and/or you may not have forever to do the job so you have to dig in more and suffer later—or pass on the job.)
 
light pressure is needed to not flip the microburr over to the other side. sometimes you don't want the flipping for weakening but simply want to grind off the microburr
 
annr said:
Depends on the conditions as others have stated, and there are many pressures between light and heavy.

Also, I think it’s important to consider yourself. Even when “heavy” pressure might work well, how long are you going to have to apply the pressure and for how many knives? Some people’s bodies (or techniques) do not tolerate prolonged periods of intense grinding. Versus will it take forever to grind the knife at a lighter pressure? Either way you may have to change up the pressures, the stones and/or take breaks. (Obviously too much pressure can ruin a job at a particular stage, and/or you may not have forever to do the job so you have to dig in more and suffer later—or pass on the job.)
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Good point.^

Too much heavy pressure for too long takes a toll on the hands, wrists, maybe even the back and shoulders (it does in my case). As I've gotten older, I've really noticed how sore my hands, fingers & wrists are for a day or two after I've done some major sharpening jobs. Even 10 years ago, I also noticed that exerting all that pressure is very fatiguing on the hands in the moment the work is being done, even if my hands weren't ending up as sore as they get nowadays. Fatigue invites loss of control and sloppier work.

Find stones that cut the steel easily at moderate-to-light pressure. This means using abrasives appropriately hard as compared to the hardness of the carbides in the steel, and also choosing a working grit size that removes as much material as necessary in a minimum amount of time. Also, a well-lubricated stone will make things work a lot more efficiently without clogging and slowing down (a slower stone invites the use of heavier pressure to try to make up for it). That makes a big difference in how fast the work gets done and how much of your energy you have to expend in doing it.
 
jpm2 said:
As said, it depends.
I use heavy pressure on silicon carbide stones to hog off metal, like for thinning and setting the bevel. As I reach the apex, lighten up drastically and switch to diamond.
For touch ups, it's diamond only and very light pressure.

So... silicon carbide reprofiling heavy pressure, diamond finishing light pressure.
This is the fastest way I know to get the results I want.
Click to expand...

This is almost exactly the way I sharpen, too, after much time-consuming trial and error trying different methods and stones. The only difference is that I form a burr with coarse silicon carbide to make sure I've reached the apex. I've read there are disadvantages to that, so I am not disagreeing with jpm2.

David Martin said:
On knives used a lot, deli & meat market knives I take it to the coarsest stone I have, a 80 grit SiC and use plenty of pressure while setting a new bevel and creating a burr. (We don't use knives here like they do.) Remove the burr and on to the fine to finish it off. If you don't use the coarsest stone and pressure then you'll take more time getting the job done. DM
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I totally agree.

I've often wondered why people take so much more time than they need to reprofile or sharpen a knife when they could do it a lot faster by simply going to a lower grit stone.
 
MtnHawk1 said:
This is almost exactly the way I sharpen, too, after much time-consuming trial and error trying different methods and stones. The only difference is that I form a burr with coarse silicon carbide to make sure I've reached the apex. I've read there are disadvantages to that, so I am not disagreeing with jpm2.



I totally agree.

I've often wondered why people take so much more time than they need to reprofile or sharpen a knife when they could do it a lot faster by simply going to a lower grit stone.
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The reasons I’ve heard are (and I’m not agreeing or disagreeing):
If the scratch pattern it too deep, they waste time on higher grits trying to remove it; sometimes the friction is too great to deal with for an extended period of time; related to the first, if the blade is very thin with low edge angles (possibly needing a highly refined edge), the coarse grit can rip up the edge and remove too much metal—esp. softer steels.

Finally, I’ve seen some steels chip with coarser stones.
 
MtnHawk1 said:
This is almost exactly the way I sharpen, too, after much time-consuming trial and error trying different methods and stones. The only difference is that I form a burr with coarse silicon carbide to make sure I've reached the apex. I've read there are disadvantages to that, so I am not disagreeing with jpm2.
Click to expand...
David Martin said:
On knives used a lot, deli & meat market knives I take it to the coarsest stone I have, a 80 grit SiC and use plenty of pressure while setting
a new bevel and creating a burr. (We don't use knives here like they do.) Remove the burr and on to the fine to finish it off. If you don't use the
coarsest stone and pressure then you'll take more time getting the job done. DM
Click to expand...
MtnHawk1 said:
I totally agree.
I've often wondered why people take so much more time than they need to reprofile or sharpen a knife when they could do it a lot faster by simply going to a lower grit stone.
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If I'm in a hurry, I'll do full length burr with the coarse stone, but the second I start detecting it, I'll lighten up to reduce flexing the edge. I'm more concerned with damaging the metal behind the apex by bending it back and forth with heavy pressure. The thinner the edge and/or lower the angle, the greater the chance of this happening.

The great thing about coarse silicon carbide is it cuts decent and you can use heavy pressure without damaging the stone, and they are inexpensive.

The great thing about diamond is it cuts the best of all abrasives, with the least amount of pressure, keeping metal fatigue to a minimum.
 
Yes ^.On commercial knives they are the worst and they will need a full sharpening every 3-4 weeks. The bevel will be convex and alignment off, plus they will have nicks. I keep flexing to a minimum by keeping my fingers at the bevel. On a good SiC coarse or x coarse stone an 8" or 10" blade will take about 15 mins. to reset the bevel and another 15-20 mins. to work off the burr, correct the point or choil, deal with chips and finish it off clean. My finish stone is usually a Norton fine India. So, yes I use pressure on these. On pocket knives customer / individuals I
don't have to use as much pressure. DM
 
annr said:
The reasons I’ve heard are (and I’m not agreeing or disagreeing):
If the scratch pattern it too deep, they waste time on higher grits trying to remove it; sometimes the friction is too great to deal with for an extended period of time; related to the first, if the blade is very thin with low edge angles (possibly needing a highly refined edge), the coarse grit can rip up the edge and remove too much metal—esp. softer steels.

Finally, I’ve seen some steels chip with coarser stones.
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These are all possibilities I consider and try to prevent when using very low grits.

One reason I'm not as concerned as I might be about creating problems forming a burr with abrasives at 100 grit or under is that I like coarse, toothy, utility edges at 400 grit and under. So I don't have to take into account factors that those who prefer smooth, refined edges might, such as deep scratches that could take a long time to polish out.

I don't have the time or patience to spend any more time than I have to reprofiling, so usually use grits down to 50 (stones, sandpaper, emery cloth) to hog off a lot of metal as quickly as possible. I only need to reprofile once (if I need to reprofile at all) so deeper scratches are eventually removed by normal sharpening at higher grits. I also might have to remove a lot of metal if I had heavy edge damage but I only buy high quality knives to help avoid this problem, and try my best to make sure the edges I put on are tough enough to prevent damage. After reprofiling, unless I'm just touching up the edge with a higher grit (in my case, around 400), I usually first sharpen with a Razor Edge Systems or Norton Crystolon coarse stone, which are around 120 grit, then finish around 400 with a diamond plate.

The possible disadvantages I mentioned about apexing with what is usually considered a very low grit (below 100, although I'm sure some would consider 400 to be a very low grit) are some of the same reasons you gave, such as a rough "serrated" edge and chipping from too coarse of a grit. So far, because I choose my knives (mostly medium and large fixed-blades for wilderness use) and edges carefully for the work I want them to do, I've not had much of a problem using grits below 100. I am also a big believer in microbevels, so adjust the edge angle to the toughest job each knife will do while still keeping a relatively thin primary grind.

A major factor in all this, besides abrasives and sharpening methods, is the many different types of knife steels. There are big variations in steel composition, how each one performs on what materials, and how it sharpens.
 
Lean it with the coarse stone but not right up to the apex - it can fold more than just the burr, and you'll be dealing with a wire edge.

Realistically, if you have a good selection of stones you should only need to lean on it for the first few passes - just like when working with a file on lower RC steels. Once it "removes the glaze" and the abrasive starts digging in I dial it way back and rely more on speed with a firm pressure, but nothing crazy.
 
MtnHawk1 said:
I also might have to remove a lot of metal if I had heavy edge damage but I only buy high quality knives to help avoid this problem, and try my best to make sure the edges I put on are tough enough to prevent damage. After reprofiling, unless I'm just touching up the edge with a higher grit (in my case, around 400), I usually first sharpen with a Razor Edge Systems or Norton Crystolon coarse stone, which are around 120 grit, then finish around 400 with a diamond plate.
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That's why it's good to define terms in a discussion! You finish where I typically start. (I hope to not go below DMT 320-600 and may polish up to 60K.)

The other consideration is the grind. Double hollow ground being much thinner more fragile, lower blade angle to begin with-- and the chisel grind. The chipping I mentioned occurred on 2 chisel grinds (one was Wenger 440C) using the DMT 320. So, now I have to repair that one...and I wasn't doing anything fancy...
 
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