Edge Retention : Cardboard

Basic methodology :

edge bevel at 4-8 dps
micro-bevel at 14-16 dps, 600X DMT fine (25 micron)
slicing cut made through 2" of straight section of blade
sharpness is the edge length required to cut a cord under tension
cut speed is approximately 1 fps

In addition :

edges are checked under 50X mag before and after use
edge are reset (destressed) before sharpening
bevel before micro is set with a 700-1000 grit stone (10-15 micron)

Cardboard details :

1/8" ridged cardboard
random sampled
population has minimum 100:1 ratio over sample size
checked on a standard blade to ensure no long term drifting

General steel classes

Class I

low hardness / carbide volume
1050, 420J2, AUS-4A
50-57 HRC

Class II

moderate hardness / carbide volume
O1, AEB-L, ATS-34
58-62 HRC

Class III

high hardness / carbide volume
D2, M2, ZDP-189, 10V
62-72 HRC

A few general notes :

the classes overlap so in the extremes they will be similar
the difference in classes are large enough to be noticed in normal use
an extreme in one aspect can dominate (hardness, carbide volume)

In regards to the values :

5.0^-0.1(0.4)

means :

5.0 is the median performance
-0.1 is the change that the last run made to the median
0.4 is the standard deviation

As a rough check, as long as the runs are changing the median by more than the standard deviations it is unlikely the result is stable (i.e. the true value).

Edge retention by Class on 1/8" cardboard at 15, 10 and 5% of optimal sharpness
Class	# runs	Sharpness	15%	10%	5%
Class	# runs	Sharpness	cardboard cut (m)
I	29	70^{+ 0}( 6)	1.4^+0.0(0.2)	4.0^+0.0(0.4)	21^{+ 0}( 2)
II	27	90^{+ 0}( 5)	3.1^-0.0(0.3)	8.6^+0.0(0.7)	43^{- 0}( 3)
III	27	79^{- 1}( 5)	4.0^-0.1(0.5)	11.6^-0.5(1.3)	65^{- 2}( 7)

A summary table where the same steels are combined :

Edge retention on 1/8" cardboard at 15, 10 and 5% of optimal sharpness
Steel	Hardness	Sharpness	# runs	15%	10%	5%
Steel	Hardness	Sharpness	# runs	cardboard cut (m)
Class I
420J2	< =56	94⁺¹⁵(37)	21	1.0^+0.1(0.1)	3.0^+0.2(0.3)	18^{+ 2}( 2)
L6	54-56	75⁺¹⁰(11)	5	1.6^-0.1(0.4)	4.3^-0.5(0.7)	21^{- 2}( 3)
1084	54-56	83^{+ 4}(14)	12	1.2^-0.3(0.2)	3.5^-0.5(0.4)	19^{- 2}( 2)
440A		63^{- 2}(24)	7	1.5^-0.1(0.2)	3.9^-0.1(0.4)	16^{- 1}( 1)
12c27m	57-58	60^{- 5}(14)	3	1.8^+0.4(0.3)	4.9^+0.9(0.7)	23^{+ 3}( 3)
SM-100	59-60	75^{+ 0}(18)	11	1.7^+0.0(0.3)	4.3^-0.2(0.6)	20^{+ 0}( 3)
cKc-X		83^{+ 0}(21)	10	1.4^+0.1(0.2)	4.2^+0.1(0.4)	25^{+ 1}( 2)
Class II
50100-B, 52100	58-60	75^{- 8}(16)	9	3.0^+0.1(0.3)	8.1^+0.1(0.8)	38^{- 2}( 3)
8Cr13MoV	59-61	97^{+ 3}(14)	12	2.7^-0.2(0.4)	7.5^-0.6(0.8)	39^{- 2}( 4)
VG-10	58-60	83^{+ 0}( 9)	31	3.9^+0.1(0.3)	9.7^+0.2(0.7)	42^{+ 1}( 3)
AEB-L	60-62	107^{- 0}(15)	24	4.0^-0.1(0.4)	10.7^-0.2(0.9)	53^{- 1}( 4)
O1	58-62	79^{+ 0}( 9)	16	2.7^-0.2(0.3)	8.6^-0.5(0.9)	57^{- 2}( 5)
Class III
S30V	58-60	73^{+ 2}(12)	25	3.0^+0.1(0.3)	9.6^+0.3(0.9)	57^{+ 1}( 5)
Elmax	58-63	83^{+ 4}(16)	21	3.8^-0.1(0.5)	11.9^-0.1(1.3)	74^{+ 2}( 7)
1095	65-67	94^{+ 0}(28)	6	6.5^+0.7(1.0)	16.1^+1.4(2.4)	70^{+ 4}(10)
M4	60-64	83^{+ 0}(15)	11	5.7^+0.4(0.9)	17.5^+1.8(2.4)	103⁺¹³(14)

The full table showing the results of each knife. Note the following data, note the color codes :

damaged steel/heat treat issues
edge instability / excessive carbide volume

Edge retention on 1/8" cardboard at 15, 10 and 5% of optimal sharpness
Knife	Steel	Hardness	Sharpness	# runs	15%	10%	5%	pps
Knife	Steel	Hardness	Sharpness	# runs	cardboard cut (m)			pps
Class I
Wiltshire Utility	TiN	72-84	35⁺¹⁰(11)	2	0.7^+0.0(0.2)	2.8^-1.0(0.6)	21^{- 8}( 5)
Ai De Chef - Roast			60⁺²¹(65)	5	0.8^+0.0(0.1)	2.9^+1.3(0.5)	20^{- 8}( 4)
Endura Carving			43⁺²⁰(11)	2	0.6^+0.5(0.1)	2.2^+1.2(0.5)	13^{+ 7}( 3)
Galaxy Cleaver			38^{+ 1}( 8)	3	1.0^-0.0(0.1)	4.0^+1.0(0.5)	20^{+ 2}( 4)
Everyday Basics Santoku			54^{+ 8}( 8)	2	1.2^+1.0(0.1)	3.4^+2.5(0.4)	17^{+ 8}( 3)
CC Chef	420 J2		94⁺¹¹(20)	4	1.4^+0.3(0.1)	4.0^+1.0(0.4)	20^{+ 3}( 3)
J. Marttiini Fillet	420 J2	53-54	68^{- 3}(24)	3	1.1^+0.2(0.1)	4.0^+1.0(0.5)	24⁺¹( 4)
Point Guard	420J2	54-56	38⁺¹⁹(23)	2	0.1^+0.0(0.1)	0.7^+0.6(0.1)	7^{+ 5}( 1)
MT 151	440A		50^{+ 0}(11)	5	1.4^+0.0(0.1)	3.6^+0.0(0.3)	15^{+ 0}( 2)
McCullen	SM-100	59-60	60^{- 7}( 8)	5	2.0^-0.1(0.3)	5.3^+0.3(0.8)	23^{+ 2}( 4)
cKc	SM-100	59-60	86^{+ 0}(19)	6	1.3^-0.1(0.1)	3.7^-0.2(0.4)	17^{- 1}( 2)
Douk Douk	1075	52-53	68^{+ 1}( 8)	5	1.5^+0.3(0.2)	4.7^{+ 0.6}(0.5)	29^{+ 2}( 4)
Bushman	1084	54	71^{- 4}(10)	4	1.4^-0.5(0.1)	4.4^-1.1(0.4)	13^{- 4}( 2)
small Peasant	L6	54-56 HRC	66^{+ 1}( 6)	5	1.4^-0.1(0.2)	4.0^0.0(0.5)	20^{- 2}( 3)
Svord 350B	L6	54-56 HRC	75⁺²³(21)	2	2.0^-0.6(0.3)	5.0^-1.0(0.8)	25^{- 1}( 5)
Opinel	1084	54-56	100⁺¹⁵(30)	6	1.4^-0.4(0.2)	4.0^-1.0(0.6)	25^{- 8}( 5)
Havalon Piranta			60^{+ 0}(12)	1	2.4^+0.0(0.3)	5.6^+0.0(0.7)	20^{+ 0}( 3)
Hudson Bay Camp	Z50Cr14	52-54	68^{- 8}( 8)	3	1.5^-0.6(0.4)	4.5^-1.5(0.6)	24^{- 8}( 4)
Crater	420HC	55-59 HRC	83^-11(12)	6	2.0^-0.1(0.2)	5.0^-0.0(0.6)	21^{- 1}( 3)
PC Chef	X55CrMoV14		71⁺¹¹(15)	2	1.0^+0.4(0.2)	3.2^+0.6(0.6)	21^{- 2}( 4)
MPU	440A		79^{+ 1}(10)	2	1.9^+0.2(0.3)	5.1^+0.6(0.9)	24^{+ 3}( 5)
cKc-X (t)	cKc-X		79^{+ 4}(18)	4	1.2^+0.3(0.1)	4.2^+1.0(0.5)	28^{+ 7}( 4)
cKc-X	cKc-X		88^{+ 0}(17)	6	1.5^+0.0(0.2)	4.3^+0.0(0.5)	24^{+ 0}( 4)
ESEE-3	1095	55-57	94⁺³⁸(31)	3	2.4^+1.0(0.5)	6.2^+1.7(1.4)	28^{+ 2}( 8)
Condor Bushbuddy	1075	56-58	58^{+ 2}( 9)	3	1.0^-0.3(0.1)	4.0^-0.0(0.6)	26^{+ 3}( 5)
Pacific Salt	H1	57-58	68 ^{+ 0} ( 5)	3	1.4^-0.3(0.2)	4.2^{- 1.3}(0.7)	24^-10( 5)
Junkyard Dog	13C26	55-57	94⁺¹⁶(20)	3	2.3^+-.2(0.4)	5.8^+0.1(1.5)	25^{+ 4}( 4)
Mora #1260	1095	58-59	107⁺¹⁹(27)	5	1.8^+0.2(0.2)	4.1^+0.3(0.4)	16⁺¹( 2)
Leuko	12C27m	57-58	94^{- 0}(10)	1	1.7^+0.0(0.4)	4.9^+0.0(1.0)	26^{+ 0}( 6)
Mora 2000	12C27m	57-58	54^{+ 4}( 4)	2	2.0^+0.7(0.2)	5.0^+1.5(0.6)	21^{+ 5}( 3)
Boker Rhino	12C27		83^{+ 8}(24)	5	1.5^+0.5(0.1)	5.0^+1.0(0.5)	34^{+ 6}( 5)
Class II
Uddo Puukko	O1	58-59	75^{+ 0}(11)	6	3.1^-0.7(0.4)	9.3^-1.0(1.2)	52^{+ 1}( 8)
Twistmaster	Carbon V	59	75^{- 0}( 9)	4	2.6^-0.0(0.3)	7.3^-0.1(0.9)	37^{- 0}( 5)
AK 47	AUS-8	59	54⁺¹⁴(13)	4	1.8^+0.1(0.3)	6.5^-0.2(1.0)	45^{- 2}( 9)
Basic #10	INFI	58-60	75^{- 8}(34)	4	3.5^+0.8(0.5)	8.6^+1.3(1.3)	36^{+ 1}( 6)
Japanese Utility	1080	60	94^{+ 5}(19)	4	3.7^+1.0(0.9)	9.9^+1.9(2.7)	48^{+ 3}(16)
Great Eastern	1095		91^{- 3}( 6)	6	2.8^-0.4(0.5)	7.7^+1.3(1.0)	40^{- 9}( 6)
ZB 786	8Cr13MoV		91^{+ 8}(14)	4	2.7^+0.8(0.3)	7.3^+2.2(0.6)	37⁺¹³( 5)
SRM 710	8Cr13MoV		117^{- 8}(17)	6	2.8^-0.7(0.4)	8.0^-1.6(1.0)	44^{- 5}( 7)
Blackjack Small	52100		88^{- 6}(17)	2	3.6^+0.7(0.5)	9.9^+1.6(1.9)	50^{+ 5}(12)
Ratweiler	52100	58-60	63^-63(16)	3	4.0^+0.4(0.6)	9.7^+0.6(1.6)	37^{- 4}( 7)
Meadowlark	8Cr13MoV	60-61	94^{+ 0}(11)	4	2.7^+0.4(0.3)	7.3^+1.0(1.0)	36^{+ 4}( 6)
K08	MBS-26	60-61	95^{+ 1}( 9)	3	2.9^+0.7(0.4)	7.9^+1.5(1.1)	41^{+ 4}( 7)
Serrata	D-440C		63^{+ 0}(10)	5	1.9^-0.2(0.6)	4.9^-0.6(0.5)	21^{+ 0}( 2)
Fallkinven H1	VG-10	59	63^{+ 8}(13)	3	3.6^+0.8(0.6)	8.8^+2.3(0.9)	35^{+ 8}( 7)
Temperance 2	VG-10	58-60	73^{+ 5}( 8)	6	4.2^-0.1(0.6)	9.8^+0.1(1.4)	37^{+ 2}( 6)
Lum	VG-10	58-60	100^{+ 6}(17)	7	3.3^-0.4(0.3)	8.7^-1.0(0.8)	42^{- 4}( 5)
Delica (wave)	VG-10	58-60	94^{- 4}( 9)	6	3.2^-0.4(0.4)	7.8^-1.0(1.0)	33^{- 4}( 5)
Persian	VG-10	58-60	79⁺²³(16)	5	3.8^-0.7(0.8)	10.9^-1.1(1.3)	54^{+ 3}( 8)
ErgoSlice	N690	60	65^{+ 2}(10)	6	3.6^+0.2(0.6)	9.2^+0.3(1.6)	40^{+ 1}( 8)
Miyabi Chutoh	VG-10	60	94^{- 3}(11)	5	3.5^+0.2(0.4)	9.6^+1.1(0.9)	48^{+ 7}( 7)
McCulleun Chef	14C28N	59-60	97⁺¹⁸(22)	4	3.5^+0.4(0.5)	8.9^+1.3(1.7)	56^{+ 9}(12)
cKc Victorious	AEBL	60	107^{- 4}(29)	6	5.5^+0.1(0.6)	13.5^+0.8(1.5)	51^{+ 6}( 8)
cKc mule	O1	60	79^{+ 4}(18)	4	3.8^-0.8(0.7)	11.0^-1.5(2.2)	58^{- 4}(14)
cKc micro-hiker	AEBL	61	75^-28( 8)	7	2.6^-0.0(0.2)	7.0^+0.3(0.5)	34^{+ 3}( 3)
cKc micro-hiker (A)	AEBL	61-62	125⁺¹⁸(11)	6	5.7^-0.4(0.8)	16.2^-0.3(2.4)	83^{+ 6}(16)
cKc micro-hiker (B)	AEBL	61-62	111^-14(17)	5	5.2^-0.9(0.9)	13.5^-2.4(2.0)	65^-23(12)
cKc utility	O1	62	79^{+ 4}( 7)	6	2.0^-0.1(0.3)	7.2^-0.3(1.2)	52^{- 2}(12)
cKc Chef	AEBL	62	88^{+ 5}(11)	3	3.6^-0.9(0.5)	10.9^-4.8(1.5)	64^-25(11)
Class III
Gavko Spartan	3V	59-60	75^{+ 4}(32)	3	4.0^-1.0(1.0)	10.8^-1.0(2.9)	52^{+ 7}(17)
Gavko Flipper	S35VN	59-60	81^{- 2}(19)	4	3.9^+0.7(0.8)	11.9^+2.1(2.8)	70⁺²²(20)
PXL	SGPS	62	94^{+ 0}(15)	5	4.8^-0.2(0.4)	12.4^-0.3(1.1)	56^{- 1}( 6)
SureFire Delta	S30V		58^{+ 3}(17)	4	1.5^+0.2(0.2)	5.5^{+ 0.8}(0.9)	40^{+ 8}( 9)
RSK	S30V	58-60	84^-10(29)	3	1.6^+0.1(0.2)	4.7^{+ 0.1}(0.6)	26^{- 1}( 4)
Small Sebenza	S30V	58-59	71^-23(15)	4	4.1^+0.7(0.5)	12.0^+1.4(1.5)	66^{+ 2}(10)
Paramilitary	S30V	59-60	67^{+ 2}( 8)	6	3.9^+1.0(0.7)	11.5^+2.2(2.3)	64^{+ 3}(15)
Nilakka	S30V	59-60	84^{- 4}(29)	3	3.1^+0.4(0.5)	10.3^+1.8(1.7)	69⁺¹⁶(14)
South Fork	S30V	60	97⁺¹¹(22)	6	4.2^-0.4(0.5)	13.7^+0.4(2.1)	93⁺¹⁹(15)
Delica	SuperBlue	62-63	97^{+ 3}(13)	6	4.5^+0.2(0.6)	12.3^-0.5(1.8)	61^-13(11)
Marcus Lin	ATS-34	60++	68^-26(21)	3	5.4^+0.8(0.9)	15.7^+3.2(3.0)	83⁺²²(19)
Safari Skinner	D2	61-62	125⁺²⁷(49)	4	6.0^+0.4(1.1)	16.3^-1.1(3.2)	85^-32(20)
ZT 0561	Elmax		50⁺¹²( 8)	4	1.9^-0.1 (0.2)	6.5^{- 0.5} (0.9)	41^{- 2}( 7)
cKc ProtoType (Burnt)	Elmax	60	58^{+ 3}( 9)	5	2.7^+0.6 (0.4)	7.9^+1.1 (0.8)	41^{+ 2}( 7)
cKc Slipjoint	Elmax	60	100^{- 0}(14)	6	5.8^+1.0 (0.9)	18.0^+1.7 (3.0)	112⁺¹²(23)
Johnson utility	O1	63.5	93^-10(23)	5	4.9^-0.2(0.6)	15.1^-0.4(1.5)	94^{- 0}(12)
Marcus Lin	1095	60++	125⁺²⁵(24)	5	6.8^+0.8(1.0)	16.3^+1.2(3.3)	68^{+ 1}(16)
Johnson Paring	1095	66	68⁺¹⁹(18)	2	12.2^+5.0(2.5)	25.1^+10.1(5.8)	84⁺³³(22)
Pretium	Elmax	62-63	97^{+ 3}(28)	6	6.0^-1.2(0.9)	18.3^-2.4(3.2)	109^{- 4}(23)
Richmond Artifex	m390	61	65^{- 0}( 9)	3	4.1^+0.8(0.6)	11.8^+0.6(1.0)	62^{- 9}(12)
Delica	ZDP-189	64-65	79^{+ 4}(13)	6	6.2^+0.5 (0.8)	19.5^+2.2 (2.9)	120⁺²⁰(22)
Air	CPM-M4	62-64	83^{- 8}(16)	4	6.1^+1.8 (0.7)	18.8^+3.0 (3.0)	110^-15(25)
710	CPM-M4	62-64	86^{- 2}(10)	6	5.5^+1.0 (0.9)	16.7^+3.5 (3.0)	97⁺²³(22)
Modulator	S110V	61-62	53⁺¹⁷(15)	3	5.0^+2.3(0.8)	13.6^+5.7(2.3)	62⁺²⁷(13)
Coyote Meadow	CPM-10V	62.5	73^{+ 8}(11)	6	3.1^+0.2(0.4)	11.1^+0.5(1.5)	84^{+ 4}(14)
OTK EDC	k390V	64	37^{- 2}( 2)	2	1.0^+0.4(0.1)	2.9^+1.4(1.7)	13⁺⁷( 9)	300^{+ 0}(40)
Gavko	CPM-S125V	63	54^{+ 0}( 6)	7	3.2^+0.1(0.4)	9.9^+0.1(1.3)	55^{- 2}( 9)
Farid	121 REX	68-70	52^{+ 4}( 8)	6	1.6^+0.2(0.2)	4.0^+0.2(0.5)	17^{+ 3}( 2)

Graphics on the individual steels in Class I :

and Class II :

and Class III :

Comments and references

Comments can be emailed to Kitchen Knife Edge Retention Uncontrolled Cutting

Kitchen Knife Edge Retention Slicing Cardboard

Edge wear in high carbide steels as influenced by the carbide size

Edge retention slicing cardboard, some commentary on the random/systematic influences

Edge retention on cardboard : update

Most of the pictures in the above are in the edge retention album at PhotoBucket.

Last updated :	16/09/2013
Originally written:	11:29:2011