Recommendation? How many strokes on a whetstone?

Yes, I get it thank you for the clarification. Just not sure why i still get flat spots when I've kept the same angle and done the necessary strokes. But it's ok, I will keep trying to figure it out!

Thanks guys,

Bo
 
Bo-dacious said:
Yes, I get it thank you for the clarification. Just not sure why i still get flat spots when I've kept the same angle and done the necessary strokes. But it's ok, I will keep trying to figure it out!

Thanks guys,

Bo
Click to expand...

Things that may help with the learning:

1. Check out YT videos by @Jason B. ("MrEdgy") and watch his sharpening technique. https://www.youtube.com/user/MrEdgy81
2. Make sure you consistently use the sharpie approach to mark up your edges, inspect after each stroke, and see which part you're missing.
3. Start with an older/beater knife until you get consistent at your stroke.
4. I often do a few "air sharpening" strokes before I actually put the knife to the stone, trying to visualize exactly what sharpening stroke I will need on this particular blade to maintain full edge contact through the full stroke. For example, a knife with a really deep belly curve near the tip will need more handle elevation to ensure you sharpen that area correctly and keep contact with the edge. It helps to get an idea ahead of time what kind of stroke and approx how much elevation you'll need.
5. If it helps you to start at a consistent angle height, you can make an improvised angle guide from a stack of quarters, see my post on that. This doesn't guarantee a perfect edge, but it gives you a sort of 'index' to ensure that at least at the start of each stroke, you're holding the spine at the proper height to create a consistent angle. It does help.
 
Bo-dacious said:
Yes, I get it thank you for the clarification. Just not sure why i still get flat spots when I've kept the same angle and done the necessary strokes. But it's ok, I will keep trying to figure it out!

Thanks guys,

Bo
Click to expand...

This is where pictures help.

But,
its cause more strokes are needed,
something to do with
- factory edge was ground unevenly, so more strokes for the reflective portion
- uneven stroke, or uneven pressure when sharpening the reflective portion, , so that portion of the blade that is still reflective wasn't getting the same amount of abrasion, so more strokes for the reflective portion needed
- edge was chipped ... can be seen or felt with fingernail . you could just keep grinding edge until this is gone, or if you have abrasive rod that can get in there, sharpen like a serration until it catches up with the rest of the edge
 
Maxiumus: yeah I do do all of those techniques you listed but I still don't get a paper cutting sharp knife until like 4k-10k grit. But thank you for the advice, I'm glad I now know I was doing at least those things right. I'll try again on a stone soon and see what I can do.

Bucket: how much pressure should I use on say a 220 grit stone and how much pressure should I use on the stones in the thousands?

Thanks for the help guys,

Bo
 
If you still have reflected light in some parts of the blade, but not others, don't worry; this is common. If your target blade has been used a lot, it will be dull all over. But parts of the blade will be more dull than the rest. You tend to find the most dull parts near the tip of a blade and in the heel section within about 20% of the length of the blade. Give or take.

It's very, very common for me to make the bevels meet on a blade along 80% of the edge and have the other 20% still have no burr and still reflect light. Those areas are just more dull and require more grinding. So I grind more, in those areas only, until I get the entire edge apexed and form a full length burr. I tend to do "blending strokes" in between rounds of grinding. So, I work on the really dull area for maybe 30 strokes on each side, and then I do 4 or 5 full length strokes. This is to prevent any weird "steps" in the blade bevel, or other strange geometry variations.

Brian.
 
Also, the fact that you can only get a "paper cutting edge" from higher grits might indicate that you have not formed a full length burr, and thus made the bevels meet. I can't overemphasize the importance of the burr. Making a full length burr is what you want to do every time, particularly when you are building your skills. It's the most consistent way to insure a sharp edge. After I started doing this, everything changed for me with sharpening. It was one of my first big "Ah ha!" moments.

I've documented this with a good bit of detail in my Seven Secrets of Sharpening. You might enjoy reading it. Or not.

Good luck.

Brian.
 
When I mentioned uneven pressure,
its just what happens sharpening one handed (stone in other hand) when you're new/wobbly, or are worried about digging out diamonds,
the tip portion or the belly portion or the before belly portion
either isn't contacting the stone at all
or is barely contacting the stone just kissing it, skating on the stone below the psi required for abrasion
belly/tip portion is what usually contacts the dinner plates takes more damage needs more strokes anyway
...
if you watch waterstone sharpening videos you'll see one hand on the knife handle, other hand on the blade applying finger pressure where it contacts the stone, and walking the fingers accross the blade...
but japanese knife bevels can be an inch wide ..

Bo-dacious said:
Bucket: how much pressure should I use on say a 220 grit stone and how much pressure should I use on the stones in the thousands?
Click to expand...

So coarser stones or finer stone, you use the same ballpark amount of pressure.

Or, as said before,
just enough pressure so the stone cuts (grabs not skates),
but not so much as to roll/deform the edge
or damage the stone.

The smaller the bevels (contact area) the less force you use
but basically like brushing teeth for shaping/creating a burr (.5-1lb),
wider bevels press harder (1lb-3lb or more),
deburring/microbeveling much lighter like touching pointy pencil/pushpin (.1lb)



0-1lb-3lb seems to cover almost all combinations for hand sharpening
and also happens to be comfortable and easy to apply with one hand (knife hand), esp if stone is other hand.


1 psi https://www.wolframalpha.com/input/?i=(1lbf/(1inch*1inch)) to psi
1/3 psi https://www.wolframalpha.com/input/?i=(1lbf/(1inch*3inch)) to psi
8.467 psi https://www.wolframalpha.com/input/?i=(1lbf/(1mm*3inch)) to psi
12.7 psi https://www.wolframalpha.com/input/?i=(1lbf/(1mm*2inch)) to psi
25.4 psi https://www.wolframalpha.com/input/?i=(1lbf/(1mm*1inch)) to psi
no 846.7psi https://www.wolframalpha.com/input/?i=(1lbf/(3inch*10micron)) to psi
no 129 psi https://www.wolframalpha.com/input/?i=(1lbf/(1mm*5mm)) to psi
no 64.5 psi https://www.wolframalpha.com/input/?i=(.5lbf/(1mm*5mm)) to psi
32.3 psi https://www.wolframalpha.com/input/?i=(.25lbf/(1mm*5mm)) to psi
16.13 psi https://www.wolframalpha.com/input/?i=(.125lbf/(1mm*5mm)) to psi


A pencil and paper and scale can help you calibrate/correlate your hand force lbs feelings ,
so you can always refer to pencil/paper later on when you're away from scale
visualize Pressure



different stones tolerate different pressures from different steels (weird but true)
reading too much stuff and watching too many videos doesn't always help
its probably more information than you need to know but its the same basic point
the amount of force you use on wide bevels is more than smaller bevels, and the apex/microbevel is the smallest so go light

Part of Sharpening playlist by Cliff Stamp

The writeup (includes PSI info) Shapton Professional 220
for this video Shapton Pro 220 : Japanese sharpening stone - a word about pressures, areas and steel types - Cliff Stamp
 
Yup. As far as pressure goes, you're just looking for it to be even on the blade. The actual amount will always require some experimentation with the particular stone, as different stones will respond differently to different degrees of pressure, and the contact surface area will impact it as well, since it spreads out the force you're applying. Get to know your stones and you'll figure out the best pressure to use.
 
Brian: That is very useful information. Thank you, I will use that for sure. And I am definitely interested in the seven secrets of sharpening. Should I just google it?

Bucket: thank you. I have a better idea of the pressure I should use now. So, an example of a wider bevel be a scandi grind, right? That video was very helpful.

Forty: thanks, I'll keep trying different pressures when I sharpen my next blade on a stone.

So if I don't get a burr at 10 strokes, should I keep going on that side until I get a burr, or switch sides?

Thanks guys,

Bo
 
Bo - where are you located?
maybe you are nearby somebody that can show you hands on and help out?
 
i would absolutely see if the local knifemaker is willing to show you something.
sometimes, especially with this subject, seeing something is so much better than reading about it - and showing is so much better than trying to type it out.
 
bucketstove said:
Hi,
How many minutes is that in strokes? In stone changes? In clamping/angle setup?
Click to expand...

OK Buck my man I finally have an answer for you.
A worst case answer (but not including any reprofiling or fixing the angles from the factory).
Some stupid hard steel; M4
The blade wasn't particularly finished on the bevels to start with meaning when I got the knife quite a while ago I angled the stones up enough off the bevels to get at the edge on both sides and sharpened the knife for a user. I suppose one could call this a micro bevel but not intentionally. Effectively a micro bevel on one side I suppose.

From there for six months or so I just touched up the knife with the ceramic Spyedrco Ultra Fine triangle rod held free hand and some where during that time I did the above half fast sharpening again on the Edge Pro. Always each time the edge was at least hair whittling so not nice to look at but very usable.

For a while now I have known I needed to flatten the Edge Pro Shapton Glass stones so today was the day. I started the clock and went and got the Edge Pro, took it out of it's bag and set it up on the counter. Got out my 10inch DMT coarse / extra coarse diamond plate and the neoprene mat to protect the kitchen counter.

As I would grab a stone, starting with 220, I would wet it and flatten it on the DMT and then use it in the Edge Pro. When I got a lot of metal on the stones I would rinse them under the faucet rubbing with my finger and if the metal wasn't washing off nice I would use the slurry on the DMT to clean the pores of the stone rather than use the Nagura.

Initially I used the sharpie to mark the edge and set up the angle to hit the bevel in the middle so I would have one sharpening bevel all the way to the edge. This caused me to take longer to sharpen than I would have liked today but made me think of you and so decided this was the post you would "like best" . . . because this is going to take for ever.

Looking back, for this M4, I would have used the DMT Aligner diamond stones initially to speed things up but figured this would be the perfect "takes for ever" example.
So anyway . . .

I have the stop collar for my Edge Pro so once I got my setting figured out I set the collar so that I could quickly use that for a datum for all the other adjustments so as to compensate for stone thickness differences for the remaining three stones = 500, 1,000 & 4,000. For those not familiar this means I don't have to use sharpie when changing stones to be SURE I am on the edge each time.

How does Wicked Edge do this ? Serious question.

I washed the slurry off the 10inch DMT and flattened the 500 stone and as I worked through all the rest of the stones I used the MO described above.

End result : one flat sharpening bevel per side all the way to the edge and a hair whittling edge.

With two pee breaks and cleaning up and putting everything away : 1hr. 50min.
yes that is way too long but that can be shortened by these factors which is my norm :
Pre established single bevels all the way to the edge on each side.
Softer steel think VG-10 or CTS-XHP.
Coarser or harder (diamond) stone to start with; ~ 120 diamond (I hate my 120 shapton = too soft).
Skip the stone flattening; I definitely do not flatten every time but today decided that for my M4 it deserved the best treatment.

Next time I touch up this M4 will go fast and I will post that time. I will miss touching up with my hand held ceramic rod though. Nothing responds to that rod for me like this M4.

Side notes : The bur I got was almost nonexistent and I didn't even have to try to get rid of it with my normal "tricks". There was simply nothing to see or worry about at the end of the 4,000 stone.

To start with the edge wasn't too dull but it was poorly formed from all the Ceramic rod work so I feel that balances out ( I had to cut the bevels flat again which takes longer than sharpening a dull edge).

Sure a belt sander and a paper wheel would have been faster but I have a strong aversion to over grinding my blades which shortens the useful life of the knife , I would rather take a while and take off almost no significant quantity of steel and yet, in the end, have a better performing geometry.
 
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