This custom from Pinoy Knives knife was made by stock removal from full hard M2 high speed steel. The blade stock is 0.155" thick with a light distal taper. The blade is 10.5 cm in length and 2.8 cm wide at maxium. The knife weighs 160 g and is handle heavy in balance. The primary grind is full flat which tapers to an edge ground at 0.027 (4)" thick at an angle of 16.7 (2.1) degrees per side. The tip is about 3.7 cm long with the thickness 0.130 at the start of the grind, and the blade is 2.6 cm wide at that point. The handle is nicely contoured and fits well in hand. A couple of shots :
The first part of the review are stock tests and general use with the knife with the NIB edge geometry, both with the initial finish as well as after sharpening.
The initial Sharpness was above average, the knife could shave well through the tip though required a draw near the choil and was scratchy. It took 130 (33) g to cut the light thread and 1.49 (14) cm to slice the 1/4" poly under a 1000 g load. With a 50 lbs push, the tip sank to 144 +/- 8 pages into a phone book, on a hard vertical stab the penetration was XXX +/- XXX pages.
The knife was then used in the kitchen and was able to cut even tomatoes with no slippage. The corrosion resistance was very high, no patina was seen even after cutting onions and letting the blade sit on the counter while the rest of the meal was being prepared. This shows a level of corrosion resitance much higher than simple steels like 52100.
In terms of raw cutting ability, on thick vegetables the custom was significantly behind a truely optomized kitchen knife like the Japanese Utility from Lee Valley. Specifically on a turnip the japanese knife required 5.5-6.5 lbs to make a cut whereas the custom was 13-15 lbs due to the thicker blade stock and more robust edge geometry.
For general kitchen work the custom fared well as a hefty paring knife, it easily handled peeling potatoes and chunking up onions and carrots being small and light enough to be very nature in hand. It didn't work well as a utility knife as it was a bit too short and thus could not handle tasks like chopping large vegetables. While the handle is smooth, there was no problem with security even when the grip was covered with animal fats and grease.
The knife was sharpened with four minutes each on a series of waterstones, 200,800,1000 and then 4000, with 20 passes per side on CrO loaded leather. This gave a decent shaving sharpness and the ability to push cut newsprint. On thread the force required was 130.8 (9.1) g, and on the poly 1.17 (13) cm of edge were required to make a cut. Thus only a slight improvement over the initial edge. The custom was then used for some cutting on manilla hemp, on a push cut it took 40 (1) lbs near the choil, and 25 (1) lbs, no aggression was seen on a slice.
As noted in the above, the custom worked well in the kitchen, and stood out on the harder work. While it easily took apart a eight lbs chicken, this would also have been completed with a normal paring knife. However the cutstom was able to make cuts with the aid of a baton through the heaviest leg bones and was chopped into the body to break apart the spine and the ribs. This induced no damage to the edge, it was still shaving though at a reduce level. Later it was batoned through a heavy bone (2.5" wide) in a piece of salt beef, again no damage.
The edge on the custom was thinned out to put it at the same angle as a few other knives to allow for a more direct comparison of cutting ability, ease of sharpening, edge retention and edge durability.
The knife was ground on a 100 grit AO belt, slightly worn. It took ten minutes to bring the shoulder of the edge all the way down, this was grinding basically flat to the belt. The steel was not easy to machine similar to INFI and D2 in that a fresh belt was needed to produce visible sparks.
Using a 200 grit SiC waterstone the bevels where leveled to flat in about two minutes. The edge was then refined with a 800 grit waterstone for eight minutes, it took so long as there were a few large chips (0.1 - 0.2 mm deep and 0.4-0.5 mm wide) left over from the initial 100 AO belt finish [optimally these would be removed by the 200 grit stone, this was just a check to see how difficult the steel was to work]. With the edge refined two minutes were spent on a 1000 grit hone and then two minutes on a 4000. This left the edge shaving very well and easily able to push cut newsprint. The blade was then given a light stropping of three passes per side on CrO loaded leather followed by the same on plain leather.
The knife was now very sharp only requiring 95 (19) grams on the thread and reduced way down to 0.48 (16) cm on the poly. Towards the tip is was singificantly sharper than in the choil just indicating a lack of uniformity in the sharpening. With the edge in this condition the blade severed the 3/8" hemp effortlessly through the tip taking only 13.0 (5) lbs, through the choil it took 35 (1) lbs, mainly due to the much larger contact region (blade curvature is close to flat in that region), and the aggression on a slice was quite high, no slippage with only 9 (1) lbs required on a draw.
| Condition | Hemp | ||
|---|---|---|---|
| push | slice | ||
| base | tip | ||
| lbs | |||
| NIB | 25.0 +/- 0.5 | 40 +/- 1 | 25 +/- 1 |
| Honed | 13.0 +/- 0.5 | 35 +/- 1 | 9 +/- 1 |
To be frank, the lack of aggression on the slice before modification was mainly an issue with the nature of the honing, specifically too much was left to the stropping which tends to produce edges with little bite. However comparing the cutting ability through the tip a large advantage can be see which shows the significant influence edge angle alone has on cutting ability. Note the much greater reduction in efficiency through the choil, the edge is not thicker there but simply more of it comes into contact with the cutting board requiring much more force to achieve the necessary amount of pressure.
You can comment on this review by email : cliffstamp[REMOVE]@cutleryscience.com or by posting in the following thread on Bladeforums :