Knife review : Ai De Chef Roast Knife


This review consists of :

Introduction and Specifications

This is a pretty standard inexpensive roast/slicing/carving knife :

There is no copy/marketing on the blade aside from those two comments. A few specifications :

The last part is a bit odd as it is doubtful it was chisel ground intentionally. It appears as if the secondary bevel was just left out of the other side. In the pictures on the right you can clearly see that one side has a secondary bevel but the other side only has the very coarse shaping grind.

The sharpening was also fairly haphazard :

It appears that the coarse scratches were not completely removed before the edge was buffed and as well the grinding was done fast and heavy. Not much is expected out of this in regards to initial sharpness and especially not edge retention.

Overall :

It should do well :

There could be issues with :

Stock cutting

The initial sharpness was low to moderate :

In short the sharpness is low to moderate, it also :

On 3/8" hemp :

The slicing aggression seems to come just from the damage as it is not consistent, is is smooth, then bites a little, then smooth, etc.. It is also not a knife you want to cut the rope with because the knife flexes heavily just trying to cut the rope..

Handle has a few issues :

Extended Use

A few obvious negatives come from even the simple task of peeling a potato :

This knife is one of the few for which the attitude becomes "what could be worse" rather than "how could this be improved".

The lack of stiffness from the very thin steel (1/32") can not be understated. Stiffness is cubic with thickness (for lateral flexing) thus this knife isn't simply 1/4 as rigid as a 1/8" Chef's knife, the stiffness is reduced by a factor of 1/64.

This means that the blade bends trivially, even trying to slice the potato the knife will radically bend and this is further amplified by the chisel grind causing the blade to skew which has to be compensated by rotating the wrist to compensate.

On thick bread with a heavy crust :

It is actually possible to put a permanent bend in the blade by rushing the cut through the bread and using too much force.

On fish :

Now on steaking cuts the chisel grind can be an advantage depending on technique but this is also ground for a left handed cutter.

On onions and similar :

The only real cutting which the knife did not have significant problem were very soft and easy to cut foods such as :

These are so easy to cut there is so little force used that most of the issues are trivial but this also starts to be the point where it could be argued that a knife isn't even necessary. A banana for example can easily be cut with the spine of the same knife. -no issues on meats, again the coarse edge slices well -even after cooking, easy to trim fats

On meats the blade had the least problems which is appropriate as it is called the "roast" knife :

Even on cooked meats which are more difficult to cut and trim there are no issues and it can easily slice and trim fats. The only real functional concerns are :

However out of all the uses in the kitchen this is where it does the least problematic.

On heavier meat work it does just fine :

In a boning style grip is also works well. It lacks the stiffness of a true boning knife and it is a bit too wide for joint work, but these are more like it is not doing excellent. It also is one of the few cheap knives that comes with an actually formed point and thus it doesn't have penetration issues.

All the little trimings are easily cut off. The skin is trimmed and is later rendered down and everything else is used for stock. In summary, this isn't a bad knife for :

It isn't that the issues are not there, just that type of cutting is far less demanding in regards to forces on the blade so the : chisel grind and lack of stiffness are not a significant influence.

However on suses such as :

The performance is so low as to be nonfunctional and in fact starts to become hazardous due mainly to the chisel grind and very thin blade which skews and trivially bends.

Grip

Ergonomics : there are a few issues with the handle in terms of comfort :

Aside from those issues, it was in general well contoured and as long as you don't have large hands, the other issues are just a little work to fix.

Security : the handle has a rear hook and front guard, and considering what it was designed to be used for (roast/carving knife) there is little concern for security in general. It also has a much wider profile than it is thick (2.5 cm vs 1.5 cm) so it indexes well in hand and resists turning/rolling. Even working with a lubricated grip from fats/oils there were no issues. However this was slow cooking in a normal residential environment.

Durability : like most thermoplastics this handle is very resistant to damage aside from occasional scratching. The main concern is heat as it will melt/smoke fairly easy, much more so than micarta, G10 or even wood has a longer durability to exposed flame.

Miscellaneous : the attachment of the tang/handle is just a press fit with what looks like an injection mould around it. There are cutouts for a pin in the tang but there wasn't one. The tang actually came right out of the handle in the cardboard cutting.

Sharpening

Before the knife was sharpened it was modified by :

The first attempts at sharpening were not overly positive, while the steel was very easy to grind, even on softer natural stones and even stones which did not have an ideal binder/abrasive mix it had persistent problems with :

As noted in the picture at the right which is off of the equivalent of a fine India stone, the apex forms much more irregular than the size of the abrasive scratch pattern.

Even switching to a higher quality much softer cutting stone (which tends to reduce fracture and burring) does not remove the problem. As shown on the right which is the edge off a 1000 grit king, the edge is still fracturing much larger than the abrasive scratch side. Note that this is after :

The apex simply collapses as soon as it is attempted to be formed. This is again likely simply a consequence of the steel being over heated as-boxed. However after several sharpening sessions these problems receded and the edge was able to be sharpened well and it could easily do a true push cut of newsprint.

Edge Retention

As the only knife used in the kitchen, it was brought into rotation on April 17 / 2013 and lasted 5.5 weeks before it had to be sharpened. In general it mainly wore smooth however there were several points of damage on the edge which showed :

The most extensive of which is shown on the right. This combination of denting and fracture is rare and when it does happen it usually indicates a problem with the steel, in this case it makes sense considering the blade showed signs of over heating as boxed (visible scaling).

The first run on cardboard showed the expected low performance :

The random behavior is simply the edge chipping and in general fracturing which causes the blunting to scatter up and down as the edge chips out and creates a "tooth" which gives some sawing aggression, that wears smooth and the pattern repeats. This level of aggression as noted however is at a very low sharpness, less than 5% of optimal.

The sudden change and drop in sharpness comes at the point where the edge has thickened to the point it is no longer fracturing and starts to wear smooth. The results of the first

cardboard trial :

Fine DMT : Initial Run
Sharpness 15% 10% 5%
cardboard cut (m)
7 ( 1) 0 (0) 0 (0) 1.9 (1.4)

However with repeated sharpening the edge retention steadily improved and the manner of the blunting became much more consistent showing, as is very common, that the initial edge suffered from :

Fine DMT : Subsequent Runs
# Runs Sharpness 15% 10% 5%
cardboard cut (m)
4 39+17(32) 0.8+0.5(0.1) 1.6+1.6(0.6) 28+ 6( 6)

Steel

This steel is :

It is likely a variant of a 3Cr13 class steel. The main issue with it however isn't the steel but the fact that it was severely over heated by power grinding as boxed (showed visible scaling and was burnt blue-black in the tip) and likely micro-fracture with intermittent water quenching as is common. This resulted in poor experiences with ;

Until all such damaged steel was ground away at which time it started behaving as a low end Class I type steel.

Overview

Overview :

Comments and references

Comments can be emailed to cliffstamp[REMOVE]@gmail.com or by posting to the following thread :

and/or the YouTube Playlist for Kitchen Knives.

Most of the pictures in the above are in the PhotoBucket album.


Last updated : 30/05/2013
Originally written: 15/04/2013
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