Sharpening method or blade steel?

[brasileiro]

Hey guys.
Yesterday I sharpen another unknow steel from brand Premium Gourmet.
It’s a chef knife with 34cm
Method used:
Grind it on 240 grit diamond stone to put a regular bevel. It came with different different degrees on each side and on heel and tip of same side, so I used 19,3 dps to make it simetrical.
After that I moved to 600 grit diamond stone. With rubbing motion. After stabilish the 600 grit I started to use wicked edge motion (I think is called sweeping motion or trailing stroke) from heel to tip. I couldn’t remove the burr on my jig, so I lay the knife at 25dps only on burr side over a 1000 grit diamond stone, pulling the blade just like Sharpmaker very light pass.
Then I back it to my jig and strop it a little bit more then usual for me.
10 passes on one side, 10 passes on other.
5 passes on one side, 5 passes on other.
3 alternate passes on each side.
Every strop motion was just like wicked edge motion.
Result: shaving sharp!
Some friends came here for a chicken at night.
One of my friend got the knife and when I saw he was cutting chicken leg with it and using my knife like a cleaver but he almost climbed up of my knife.
I thought: it’s done, my knife is dead...
But not. The blade isn’t shaving sharp on that section anymore but steel cut very well, have no denting, no chip, and almost none bright light when look directly to apex with string light.
For me was a surprise when the knife was still alive after all.
What do you think about?
Could be the steel?
Sharpening method?
Strokes motion?
Strop?
This is a picture of the knife.
I couldn’t find any info of blade steel and here the most of people just named the blades with stainless steel with no mention of which kind of steel are the knives.
Thanks.

Edit to add.
The bevel was a crap and was rolled after few uses like slice vegetable and things like that. I pay around 24 dollars for the knife (but I don’t know if it is imported but if is the real price withou taxa goes down to around 15 dollars, so is still a cheap knife.

 

[bucketstove]

Hi,
I see what you're saying
- original bevel was uneven rolled easily, like it was burred / weakened
- you fixed it up to ... 20 degrees per side with 25 degree microbevel
- it survived chicken bone chop without rippling /rolling/ pancaking/ extreme dulling

What do you think about? Could be the steel? Sharpening method? Strokes motion? Strop?

Congratulations
Its the geometry , its always the geometry
That is its the angle and the thickness at the shoulder.
After all, even $1 kitchen scissors/shears can handle chicken bones

So save some of that chicken bone (or bone another chicken ),
and compare to another knife
for ex $1 kitchen knife
or utility razor blade ,
they come come in thickness .017in, .025,.035,
put a 15-25dps edge on utility razor and how it cuts that same chicken bone ,
0.017in and up at 15dps and up is chopper edge thickness

consider that under 15 dps edge can chop bones And 12 dps edge can still shaves/whittles beard hair after 1000 slices of hardwood ( yes a 1000 slices of hardwood )
This utility razor blade pictured here has ~10dps edge/0.017in(431.8micron), increase that to 15-25dps and try cutting up that same chicken bone, (all the other pictured knives all sharpened to 30-inclusive)

When Joe mentions 0.020" thick for chopping bone, that is roughly comparable to the green blade in the diagram above. 0.020"

 

[brasileiro]

Thanks for reply

 

[brasileiro]

Ok. Now that I read about it I couldn’t find a math relation between bevel thickness and angle except one of Cliff Stamp wrote on his forum but Cliff uses extremely low angles and this scares me.
Example of what I had in mind:
if the thickness at shoulder is up to 0.017 you should (can) use angles (dps) up to 25dps.
Or a more intuitive sample:
<0.017” - 20~25 dps
0.018~0.025 - 15~20 dps
0.026~0.037 - 10~15 dps...
to have the same cut efficiency and apex longevity.
But Cliffs relation between dps and thickness are on opposite of what I thought.
He wrote that I.e:
4~6 dps light use knife, paper and cardboard... in contrast with
0.005” light use knife, paper and cardboard...
I thought thinner the blade behind the bevel, steeper should be the angle. Or I didn’t understand.

I measure the bevel thickness of my knife and in inches is something about 0.019 and according to Cliff I could use 12~14 dps.
I know there is no absolut true and many factors can influence the relation between angle and thickness, but it could be a direction on how to start sharpening process.
Spyderco use 15 or 20 dps on sharpmaker and I think that is a safety margin but for me I still feel safe using steeper angles on my blades given my last experience.

 

[jpm2]

The geometry I sharpen at absolutely depends on the steel composition, heat treat, blade thickness, and intended use.

 

[bucketstove]

I measure the bevel thickness of my knife and in inches is something about 0.019 and according to Cliff I could use 12~14 dps.
I know there is no absolute true and many factors can influence the relation between angle and thickness, but it could be a direction on how to start sharpening process.
Spyderco use 15 or 20 dps on sharpmaker and I think that is a safety margin but for me I still feel safe using steeper angles on my blades given my last experience.

Hi,
Thats pretty much it,
choose what you think you need,
sharpen knife and see how it cuts and if it gets damaged,
if edge didn't get damage, thin the edge (grind shoulder) or lower the angle
if edge got damaged, thicken up the edge (sharpen at same angle) or increase the angle
repeat

Speaking of your last experience, rolling at 20dps -- if you're using wood/poly cutting board -- could be easily explained by poor factory sharpening job. , overheated/overpressured/damaged edge, or a heavy burr.
So Instead of increasing angle, simply sharpen it again and see what happens, you'll be surprised.
Ref As received edge retention slicing half inch inch hemp ->
global-knife.com/catra/ test on factory vs hand sharpened edges


Now back to geometry,
Some people optimize to prevent gross damage (primary ripples)
and allow more wobble (less control, less care)
and contact with metal/rocks,
so what you get is sharpened prybars or "survival" knives and beyond,
and then others people optimize for ease of cutting ,
which is important if you cut a lot like hours of cutting ,
so you get things like "fine edge" versions of kitchen/chef knives , optimized for vegetables
and cutting boards and not bones


So the way I think about edge angles and thickness,
compare your edges with your fingers/eyes to utility knife razor blade
don't need to know actual thickness numbers of your edge,
if your utility knife blades dont say how thick its easy to measure with simple centimeter/mm ruler, then compare to this list, and decide up or down

• 4 to 6 dps (8-12 inclusive) -<0.005", light use knives, paper and cardboard, light ropes, knot free woods
• 8 to 10 dps (16-20 inclusive) -<0.005"-0.015", moder push cuts on woods, thicker plastic, heavy ropes
• 12 to 14 dps (22-28 inclusive) -<0.015"-0.025", hard push cuts on very knotty woods, bones, etc.
• 12 to 14 dps (22-28 inclusive) ->0.025" dps, chopping blades
• 0.025"/15 dps (30 inclusive) = 0.635 millimeters / 15 dps edge overbuilt , cutting into or contacting against very hard materials like rock, metals and such. It is over built for cutting but well built for durability in extremes/utility.
• 0.025"/15 dps (30 inclusive) = 0.635 millimeters / 15 dps edge overbuilt , you could chisel cut through nails and such without issues , $1 one dollar knives or $5
• 0.035"/20 dps (40 inclusive) = 0.889 mm 20 dps beyond overbuilt , $1 one dollar knives or $5
• 0.045"/25 dps (50 inclusive) = 1.143 millimeters /25 dps sillybuilt
• 25 dps and 30dps (50-60 inclusive) and higher are angles for metal cutting cold chisels or splitting wedges

Its easy to see the truthfullness of this list, simply
take a box of utility knife razor blades and sharpen to see how low you can go.
Explode your mind through first hand experience not merely mind exploding videos, spyderco delica/pacific salt...Extreme Regrind , ~6DPS with 10dps microbevel, no damage in 50 slices into pine, hardwood flooring and plywood the edge eventually gets damaged while cutting metal (steel food can)

and then fear is for others