Lowering your bte thickness on stones

[Baron Mind]

I've been dabbling with regrinding my knives on stones in an effort to thin them out behind the edge and increase cutting perfomance for a while now. It's been somewhat frustrating as meaningfully impacting the blade thickness has proven challenging. Grinding grinding grinding with only minor reductions to the thickness behind the edge.

Neroknives posted a video today where instead of laying the blade flat and just adding pressure near the edge he raises the blade to maybe half of the edge angle. He says it's much faster and more effective than trying to thin the whole blade, even on a belt sander.

I'm tying it now as I've been infatuated with increasing cutting ability as of late. I'll definitely let everyone know how it goes, but my question is am I really thinning the knife out behind the edge, or just rounding the shoulder and convexing the blade. I plan on doing significantly more grinding than he does in his video, but what do you guys think?

I can link the video, but if you go to his channel it's his very latest upload.

 

[JJ_Colt45]

it all depends on how much you are raising the angle ...

if you are completely flat you are in essence reprofiling the blade to a full flat grind ... and would still have to raise the angle to put your bevel on the blade ... which is what gives you the cutting performance ...

depending on the type of knife ... the intended uses ... and the type of steel ... you can set your bevel anywhere from 12 dps for kitchen knives to 18 or 20 dps for heavier choppers ...

and then add a micro bevel 3 or 4 degrees higher ...

I hope I explained it enough it makes sense to you ...

but you are picking up on how to start sharpening the knife instead of reprofiling the blades main type of grind ...

 

[Baron Mind]

it all depends on how much you are raising the angle ...

if you are completely flat you are in essence reprofiling the blade to a full flat grind ... and would still have to raise the angle to put your bevel on the blade ... which is what gives you the cutting performance ...

depending on the type of knife ... the intended uses ... and the type of steel ... you can set your bevel anywhere from 12 dps for kitchen knives to 18 or 20 dps for heavier choppers ...

and then add a micro bevel 3 or 4 degrees higher ...

I hope I explained it enough it makes sense to you ...

but you are picking up on how to start sharing the knife instead of reprofiling the blades main type of grind ...

The blades I've been doing are full flat grinds to begin with. The goal is to thin the entire blade, especially TOWARDS the edge, but not the actual edge (although lower the edge angle of production knives to a minimum of 15 degrees per side is pretty much mandatory in my book). The lower edge angle will increase performance, or lower resistance when cutting, but how thick or thin the primary grind of the blade is, the closer to the edge the more it matter, also will affect how easily the knife cuts. That's what I'm interested in atm.

 

[Wowbagger]

am I really thinning the knife out behind the edge,

As a mechanical book I have states in the beginning : One measurement is worth a thousand expert opinions.
I know thinning and reprofiling these two took them from : Are you sure you want to call these "Knives" when Pry bar seams more appropriate ? ? ?
to . . .
Oh HELL yeah !

I went about half as thick as the factory blades both at the spines and bte !
A little slow and careful power grinding followed by very coarse large diamond file blending and further work with a very coarse 120 Shapton Pro stone.

 

[Baron Mind]

As a mechanical book I have states in the beginning : One measurement is worth a thousand expert opinions.
I know thinning and reprofiling these two took them from : Are you sure you want to call these "Knives" when Pry bar seams more appropriate ? ? ?
to . . .
Oh HELL yeah !

I went about half as thick as the factory blades both at the spines and bte !
A little slow and careful power grinding followed by very coarse large diamond file blending and further work with a very coarse 120 Shapton Pro stone.
View attachment 1185946

Nice. I'll be moving soon, and once I finally have a basement/shed/yard I'll probably get a belt sander up and running. It's just not feasible where I'm at right now.

 

[MtnHawk1]

I've been dabbling with regrinding my knives on stones in an effort to thin them out behind the edge and increase cutting perfomance for a while now. It's been somewhat frustrating as meaningfully impacting the blade thickness has proven challenging. Grinding grinding grinding with only minor reductions to the thickness behind the edge.

It sounds like you need to go to a lower grit stone.

my question is am I really thinning the knife out behind the edge, or just rounding the shoulder and convexing the blade.

Your scratch or wear pattern from the stone should tell you that.

The goal is to thin the entire blade

I wouldn't do that. It would weaken the blade, plus I like a bit of a wedging effect when I'm cutting or chopping harder materials.

 

[cbwx34]

...

Neroknives posted a video today where instead of laying the blade flat and just adding pressure near the edge he raises the blade to maybe half of the edge angle. He says it's much faster and more effective than trying to thin the whole blade, even on a belt sander.
...

Think this video shows something similar...

 

[Mr.Wizard]

Abrasives cut better with more pressure (if the bond can handle it), so placing the entire face flat makes things slow. If you keep pressure mostly toward the edge it will speed shaping, and if you overdo it and start to create an unwanted bevel or convex moving the pressure up toward the spine just a bit will shift pressure the the shoulder of that bevel and again speed cutting.

If doing this by hand I've found wet/dry sandpaper to be faster than any stone. I do want to try the Zandstra Foss stone when I can afford it, but since I discovered "3M Pro Grade Precision" paper with "Cubitron II grit" that lasts longer than SiC Wetordry and doesn't need adhesive to stay in place I am not in a hurry.

 

[David Martin]

I have done this on my ACE Hardware sic stone. The coarse side being very coarse, then move on to the finer side which is a medium grit to
blend it in. It will shed grit material but it won't take you very long to work it to a point you like. DM

 

[CasePeanut]

The coarse ACE hardware store that David mentioned or even better a Baryonyx Manticore for only a couple more bucks will do this easily. That stone is an absolute beast.