An Battle Mistress from Busse Combat made from INFI was compared to a slightly modified Coyote Meadow Utility Hunter made from CPM-10V by Phil Wilson. Both knives had seen extensive use, the sharpness of the Coyote Meadow Utility Hunter had been maintained with an 800 grit ceramic rod, and the Battle Mistress had seen occasional honing on a strop loaded with jewelers rouge. An equal length of blade was used for both knives during the cutting. The sharpness was determined by how many passes would be need to cut through a roll of fabric, and average of multiple cuts was performed. The stock cutting was performed at random locations through the marked out blade length and included :
Cutting method was critical, on the first run of the card stock the Battle Mistress tore a few cards due to handling issues while it consistently smoothly sliced through the three layers of index cards the second time. Both blades cut the pine well with the Coyote Meadow cutting about twice as deep as the Battle Mistress. Both blades were easily pressed through the RS-232 cable which was cut on a piece of 2x4 . After each of these stock rounds some paper was sliced and a little shaved performed as a bit to check for any signs of edge loss. Nothing was detected. For reference 25 cuts on the RS-232 cable with a Calypso Jr. (AUS-8) brought it below scraping sharp.
The plastic tubing showed a clear difference in cutting ability between the two blades. The thinner Coyote Meadow could simply be pressed straight through the tubing while a slicing motion had to be used with the Battle Mistress. Through the next series of cutting on pine, neither blade exhibited a difference in performance from the first session. Both blades still shaved and easily went through newspaper. Proceeding through the last fifty cuts on the RS-232 cable, the Battle Mistress didn't shave as well and slipped a little on paper. The fabric cutting specifics :
| Steel | Before | After | Loss of sharpness in percent |
|---|---|---|---|
| CPM-10V | 6.3 +/- 0.3 | 6.0 +/- 0.5 | 0 |
| INFI | 5.0 +/- 0.4 | 8.0 +/- 1.0 | 38 +/- 5 |
The blades were sharpened with the same ceramic rod and then lightly honed with the loaded strop. The fabric cutting was again used to determine the sharpness before and after the stock cutting which included :
This material was all used and thus is fairly abrasive as it contains grit and dirt. The cardboard in particular was had been lying around on the floor in the basement. Both knives sliced into the maple well, but with much less penetration than on the pine, the Coyote Meadow again removed wood about twice as fast. The tubing was softer than what was used previously so the blades easily performed push cuts. The cardboard brought out the first sign of wear as the BM ripped a couple of slices on the second round and could no longer slice paper well. The Coyote Meadow still sliced paper well at this point but the edges were a little rough. The specifics :
| Steel | Before | After | Percantage loss of sharpness |
|---|---|---|---|
| CPM-10V | 1.6 +/- 0.1 | 7.5 +/- 0.7 | 79 +/- 9 |
| INFI | 2.4 +/- 0.1 | 22.0 +/- 4.0 | 89 +/- 16 |
Again as similar to the first round, the Coyote Meadow light utility hunter out lasted the Battle Mistress in regards to edge holding. Because of the very high variance of the performance of the Battle Mistress after the final cutting in the second round a precise estimate can't be obtained, more work would need to be done to give a decently robust estimate. There are further comparisons of the two blades in the review of the Battle Mistress.
Later a Busse Basic made from modified INFI (M-INFI) was compared to the modified Coyote Meadow light utility hunter in CPM-10V. Both blades were lightly burnished with a ceramic rod and then stropped to give them a consistent finish. The sharpness was again measured by the number of slices required to completely cut through a roll of fabric before and after stock cutting to induce blunting which included :
The Coyote Meadow handled the above cutting with little effort. The #7 Basic performed highly despite being thicker, the performance was enhanced by the dropped blade and greater mass. The cutting ability was only significantly behind the Coyote Meadow blade on the wood in which case it was out cut by more than two to one, due to the more obtuse edge profile. Up until the last cutting of the rubber tubing both blades sliced paper well, after that point the Basic caught in a couple of places. After the cutting the Basic was stropped about twenty times and its edge restored. It would now slice paper effortlessly and sheared through the fabric matching its initial performance. The CPM-10V blade was not significantly effected so I just lightly burnished it with a ceramic rod. The fabric cutting specifics :
| Steel | Before | After | Loss of sharpness in percent |
|---|---|---|---|
| CPM-10V | 2.5 +/- 0.1 | 2.7 +/- 0.1 | 7 +/- 1 |
| M-INFI | 4.1 +/- 0.2 | 6.5 +/- 0.3 | 37 +/- 3 |
In short, the CPM-10V blade again shows superior edge retention on light stress work. This would be expected as it is significantly harder and has a much higher carbide alloy content.
A 62 RC knife made by Mel Sorg was then included in the cutting. All blades were sharpened with the same 800 grit ceramic rod and would shave well and cleanly slice through news-print. The stock cutting was limited to fifty slices twenty cm long slices through three mm thick cardboard. After the cutting the CPM-10V blade was not significantly blunted, the D2 and M-INFI blade showed light blunting of similar extent.
Note that the cardboard slicing was done at high speeds, as an illustration of how much of a difference this can make the Basic was used to do 125 slices through two mm thick cardboard, one run at high speed and the other slow. On the slow run the performance went from 1.7 +/- 0.1 to just 1.8 +/- 0.1, no significant blunting. However after the very fast run the performance had degraded to the extent that the Basic now took 7.3 +/- 0.3 slices, a performance loss of 77 +/- 5 %.
As a final note on edge retention, the Basic was stropped back to optimal and used to chop and slice into a piece of pine producing shavings which filled the bottom of a 30 by 45 inch box. The edge showed no loss in shaving ability and it would still nicely slice up paper. The chopping and slicing was done at a slow and steady pace with minimal twisting.
This review was written in 1999, since that time it has come to be understood that examining edge retention is a lot more involved and cannot be treated as simply as in the above. Blunting it not a linear process so sharpness tests should be carried out periodically through the stock work and not just before and after. Most high alloy steels also need to have the edges periodically reformed on hard abrasives to give maximal performance. Jewelers rouge is not an effective stropping compound, use chroimum/aluminum oxide or better yet diamond paste. Finally, while cutting fabric is informative it is difficult to make a standard how much force was used to readily compare cuts from one day to the next. Much more accurate and precise methods of testing sharpness and edge retention have been developed in the recent years.
Comments can be sent to : cliffstamp[REMOVE]@cutleryscience.com, and seen in the following thread [ARCHIVED] :
| Last updated : | Mon Mar 31 13:47:27 NST 2003 |
| Originally written : | Mon Oct 4 09:12:40 NDT 1999 |
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