Kitchen knife bevels

[Britt_Askew]

Going to grind a few kitchen knives for Santa. I have ground 3 kitchen knives so far and all 3 were full flat ground. Looking at pictures it seems like a lot of people like to grind only about an 1" or so high (saber grind?)

Which do you prefer ,pros and cons of each?

 

[HSC ///]

Well it depends...
The first 2 have tapers forged in so the grind doesn’t need to be high.

the 3rd also has a taper forged in but is ground flat to convex

In general I like a flat to convex grind.

but factors contributing to the grind include stock thickness and blade height

 

[Stacy E. Apelt - Bladesmith]

Same here. If the style is Japanese or for carving meat, I will use a shinogi line (sabre grind). On all other kitchen knives, I do FFG and usually slightly convex the edge.

 

[scott kozub]

If you're going for a high saber grind on a wide kitchen blade on thin material its very tough to get a clean grind line.

I like to blend my grinds so there is no plung line. This provides a wider bevel at the heel that get thinner towards the tip. This is useful for doing delicate work at the tip and heavier chopping at the heel.

This is the best tutorial I have seen on grinding kitchen knives.

 

[imill3567]

I’m also in the full flat grind boat but I am a stock removal maker. Lately I have also been adding a slight convexity on the rotary platen. Either way go as thin as you can on the edge. I know I still feel like I need to chase thinner geometry which would mean grinding to zero. I’ll second that it’s very difficult to have a super clean grind line on high saber grinds on thin stock (0.08”) so I also bring it all the way up and blend my plunge in.

 

[Nick-D]

On the subject, can any of you fine folks walk me through your process to achieving some consistent convexity towards the edge? My efforts so far have been functional but less than clean.

 

[imill3567]

On the subject, can any of you fine folks walk me through your process to achieving some consistent convexity towards the edge? My efforts so far have been functional but less than clean.

Well with what I specifically mentioned on a rotary platen I’m adding convexity to the whole bevel and it is very easy on a rotary platen basically the same as a flat platen. You could probably do just towards the edge and then blend it in but I haven’t tried that.

 

[scott kozub]

If you use a center scribe line along the edge and the bevels are even height on each side you should be close.

I take my blade to about 0.005 to 0.006 on the flat platen constantly checking the edge thickness with a sheet metal gage. Once I have a consistent edge thickness I'll convex the edge on the slackbelt to a zero grind or near to. I don't have a rotary platen.

Two things to be careful of:

1. The flat platen generates a lot more heat than the slack belt or rotary platen. When you start getting below 0.008 or so on the flat platen be very careful of burning the edge.

2. Once you approach zero grind on the slack its really easy to carve a valley in the edge. If you do this you have to reset the edge by chasing it back a bit. Use light pressure and keep checking for a burr. Once a burr is there move to a new spot on the blade.

 

[C L Wilkins]

Most kitchen knives are symmetrical, the edge is the same on both sides.

To throw another fly in the ointment, you can also do a right-hand or left-hand edge. This is done usually on a Japanese style knife. What that is, is that it has a chisel edge on one side, a straight edge on the opposite side. For a right-handed knife the convex, or chisel edge is on the right side, for a left-handed knife the convex is in the left-side.

Keep in mind for our discussion the picture is an exaggeration. This is for the edge done during sharpening, not for the bevels.

For example, if you order a knife such as a Masamoto chefs knife from Japan and want it to be left hand sharpened, they will take a right hand or standard symmetrical edged knife and re-sharpen it, having the convex side on the left side of the blade, the straight side on the right.

c - left-handed
b - symmetrical
a - right-handed

For more information you can do a Google search for "left handed knife".

 

[Cushing H.]

Basically X2 on what scott said. To my feel, really thin knives, with a small (0.005 or so) TBE cut/slice really well. And it’s really hard to get a clean shinogi on thin stock (0.08 or so). So I bring the grind up as far as I can, then blend

 

[Natlek]

If you're going for a high saber grind on a wide kitchen blade on thin material its very tough to get a clean grind line.

Why ? Do you grind bevels free hand or you use jig ? I never have problem with clean grind lines on thin steel say like on 1.5mm thick steel .I use jig ...........