Luong La, Bluntcut Metalworks. Multiple steels, multiple hardnesses, multiple testers

Status
Not open for further replies.
I've got the "Edge Inquisitor 3000" all tuned up - can make cut offs as small as 1/4", no contact on the follow through, divisions for distance traveled, variable load. Just need to pick up some more rope....

I don't intend to test to failure, but definitely to a notable increase in force needed to make the cut, or a doubling of the pull distance, something reasonably definitive. Plan on running vs cheap kitchen cutlery and one other, probably Sandvik 12c and/or 1095. Need to find something that matches the stock and angles close enough for meaningful comparison.

Am not sure what I can reasonably do for higher toughness testing, probably stick to retention and ease of resharpening. If there are no cracks from HT after normal cut testing (close visual inspection planned 400-640x) that will be the end of it, pounding on thin stock tools is not realistic usage.
 
HeavyHanded said:
I've got the "Edge Inquisitor 3000" all tuned up - can make cut offs as small as 1/4", no contact on the follow through, divisions for distance traveled, variable load. Just need to pick up some more rope....

I don't intend to test to failure, but definitely to a notable increase in force needed to make the cut, or a doubling of the pull distance, something reasonably definitive. Plan on running vs cheap kitchen cutlery and one other, probably Sandvik 12c and/or 1095. Need to find something that matches the stock and angles close enough for meaningful comparison.

Am not sure what I can reasonably do for higher toughness testing, probably stick to retention and ease of resharpening. If there are no cracks from HT after normal cut testing (close visual inspection planned 400-640x) that will be the end of it, pounding on thin stock tools is not realistic usage.
Click to expand...



Glad you got the knives. What about these knives scraping bone vs a kitchen knife and a field knife in comparable steels?

As an aside, I was able to pound on one of Luong's 52100 kitchen knives with a moderate level of caution. It wasn't full blown uncontrolled abuse but it was more than I do for any other kitchen knife. It did really well considering its very thin spine. I wouldn't be scared to pound on any of those knives you now have except maybe the M2 blade. They're not Busse knives but I'd be willing to bet they're tougher than a lot of knives at equal hardness and width.
 
Last edited:
Using the newly calibrated EI-3000, I have data for one of the control knives, at least for this metric.

Set up:

Test knife is Chicago cutlery Chef's knife circa 1990s, Chinese Mfg stainless.

Sharpened knife on 800 grit wet/dry over Washboard, stropped on plain paper over same. Edge was crosscutting Alliance catalog paper with a whisper but still pretty grabby - reasonably strong 3 finger sticky response.

Set the test up at 10lbs force with 3/8 sisal (local HD only had 3/8 and 3/4, no 1/2") and a pull of 2".

Became apparent fairly quickly that rope has some variation even in the same coil. Had hoped to have a fairly black/white pass/fail but not to be. Missed its first pull on #64, yet continued for another 20 passes with no hitch. Decided when it dropped three in a row it was DQ'd. That didn't happen till pass number 217. By 120 it was missing the odd pass with regularity, but it would also recover and cut another 10-12 with no missing. Finally as it approached 200 the instance of misses and the odd double miss increased, dropped three starting at 218. I continued for another 5 passes and it was unable to complete any though was still making it reliably through two of the three strands.

Edge in the test region could still pop arm hairs and crosscut catalog paper with a push though was louder and hitched a bit as it went. Three finger stick had dropped off in the test region - was still noticeable closer to the tip. Clearly this test has its limitations, but it did pick up on a level of edge degradation that would otherwise be pretty subjective.

Next test will be something higher quality and then I'll have the beginnings of a scale.

Martin
 
Continuing with the EI-3000, next test knife is a Bark River Bravo Necker in 12c27. Edge terminates at approx 26°. Perhaps a touch thicker behind the edge than the Chicago Cutlery Chef's knife, but a touch thinner at the apex to make up for it.

First stutter at 180, began to miss with increasing regularity at upper 200s. Surged thru the 300s and finally crapped out as it reached midpoint 400s - 463.

Is apparent that there is a bit of variation to the rope, enough that it needs to be taken into account. Just setting it on the rope prior to making a pull I can feel variation in how readily it bites depending. I also added a necked down tube to guide the rope into the cut path, and I can feel when a splice is coming through. All in all seems to be reasonably useful though. I expected the better steel to outperform the poorer steel and it did, by more than 2 to 1. Any testing of additional knives now have something to compare to as well as other cut tests.
 
I got em this AM but haven't opened the box yet. Will get into testing as soon as I can - this week will slow for that sort of thing due to holiday.
 
Getting into it now.

My background - lifelong outdoorsey hiking, camping etc. Work in printing. While I could always put a respectable edge on my tools, my interest in higher understanding of sharpening came about when tasked to recondition some of the cutters on various equipment around the shop over a decade ago. Also my Father in Law spent many years as a blade/cutting engineer for industry with his own staff, SEM etc, so something we can discuss regularly and compared notes.

My interest led me to develop and market a sharpening block for use with flexible abrasives, the Washboard. I also do a small amount of commercial sharpening of everything from lawn mower blades to hatchets/axes to kitchen knives, chisels etc. Most of this is done by hand though I will use a belt grinder to set bevels and for larger stock removal.

First off, all seem to be well thought out. The handles have a good feel, the edges all have a continuous curve along the entire length. All are very thin grinds except for the W2. Maintaining the edge on these will be very easy due to this thin grind, the cutting bevels are quite small. All of these sharpened up on several abrasive media quite readily despite the high Rockwell values. Burr formation was moderate, removal straightforward. The 52100 took slightly longer to resharpen than the others. I wound up lowering the grind angle a few degrees on all but the M2. Started out at just above 30° (best I could eyeball) and I dropped them down to approx 26-27.

Despite being for eval only, the overall fit and primary grind work on these is very good. I am somewhat familar with the paring/small utility pattern used by BCMW, the medium pattern is very nice in hand and use - Of the three "medium" patterns I could not settle on a favorite. The CruForge is so light it doesn't seem possible the handle/tang could hold up to abuse, but there's also no way I am going to push it far enough to find out. It would make a great EDU/constant companion for IWB or high belt carry.

Close examination at 400x revealed no cracks along the edge so far, I'll take another look before I send them off (something I always check for when steels are run close to their highest possible RC). The knives are being used on a variety of paper, cardboard, plastic skid banding. Some carving of hardwoods. I am beginning to run them thru the EI_3000, Cutting is of 3/8 sisal at 10lbs.

Started with the 52100 and got up to 500 passes before calling it for the night. It can't have much more in the tank, but I thought that when it started to balk at about 275 and it just kept going...

[video=youtube;XiWAd9RJhs8]https://www.youtube.com/watch?v=XiWAd9RJhs8[/video]
 
Awesome! That's a pretty cool tester, and thanks for your ongoing review!
 
The 52100 sample made it 1470 passes before failing the test. The first inch of edge was intact, could no longer shave arm hair but could scrape some off, still reasonably sharp all things considered. The next 1.5 inches (because the pronounced belly, more than 2" of edge makes contact as it drops) showed some rolling/deformation. I believe this must have been caused by contaminants in the rope as I heard a distinct crunching sound on two passes round about the 1200 mark, and the damage was very localized. I didn't stop to check as it kept cutting. Still the geometry and intact first inch of edge were enough to open up the rope and keep going even with this bit of damage.

I have to say this is impressive. Consider it wouldn't reliably complete a string of cuts under testing conditions (10lbs, 2" draw) with the edge at 30-32°, lowering the edge to 26-27° produced some amazing results. That also tells me it wasn't just the primary grind geometry accounting for the longevity. Minus the damage, it might have continued another several hundred cuts, strong performance for a carbon steel IMHO.

Will pick this back up after Thanksgiving weekend.

Martin
 
Just to reiterate, you're finishing all the knives with 800 grit wet/dry sandpaper using your washboard system and stropping on plain paper, right?
 
Last edited:
That's correct. I initially sharpened them up with some waterstones and back and forth with the SiC wet/dry. So far all the knives I've run on it have been at a "medium" finish done on a Washboard, stropped on plain paper, no abrasive.
 
Back to it, I had some issues with getting reliable numbers from my rope testing, so switched to Manila from sisal and now use multiple coils, swapping every 25 cuts. This greatly improved the consistency of my numbers, still hitting foreign objects in the rope from time to time but that might be unavoidable on a unit like the EI3K and the rope I'm getting from HD. The numbers are about 1/4 to 1/3 of what I was getting using the sisal. The Manila is much more rigid, twisted tighter, has more consistent diameter. Everbilt brand name.

10 lbs of force, 2" draw, 3/8 Manila.


Anyway...with numbers that make sense, I retested a number of knives. The other change I made was to switch to my Norton 4k from 800 grit wet/dry on WB as I was doing too much resharpening (and some repair) in short time frame to guarantee consistent abrasive finish with wet/dry. Edge finish appears functionally identical, am still burnishing on WB as a final step. Resulting edges can crosscut fine paper with a bit of noise, shear cut free-hanging paper towel cleanly top to bottom - good all around EDU edge.

There are minerals in the rope and I had the misfortune to hit two of them - had to resharpen and retest from the top. One of them on full convex BR actually showed singular mineral grind trough from damaged edge up onto the face of the blade. I still couldn't find it in the cut offs, but no doubts anymore. I cannot recall other folk having this issue, might have to find out what brand others are using...

The 52100 managed 112 and 120 cuts before it missed three in a row (still making it most of the way through). I then stropped/burnished on plain paper over WB and was able to make another 30 cuts. Hooray for fine grained carbon steel! High alloy stainless would not have responded so nicely - a 25% increase in cut #s with a sheet of paper and WB.

Next was the 1095, which made 105 and 124 cuts - I did not attempt another paper stropping, this isn't about me after all...

Bark River 12c27 made 86 and 98.

Old Hickory paring knife 1095 low RC made 24 and 21 cuts.

Mystery stainless kitchen knife made 32 and 47.

The chosen edge finish was not intended to generate the largest numbers, but to provide a consistent finish that would show evidence of wear for comparison. You can actually hear/feel the edge losing its bite as it dulls. All edges are thin behind the edge and were sharpened up to approx 27° inclusive.


After the edge test, all knives could still slice fine catalog paper but not pushcut. Another good sign - they had all dulled to a pretty consistent degree after starting from the same degree of sharpness. The numbers are plenty close enough for me to have confidence now.


I then took the 52100 and 1095 and repeatedly batoned thru 1" seasoned poplar at a 45° angle - about 10-15 times each. Edges showed zero wear or damage from this.

After using these for a few around the shop and home I find myself very much enjoying the ergos of the BCMW Trade Knife (my description :)) pattern. A knife in the same pattern but sized down a touch (say 3.5 inch/ 9-9.5 cm blade length, 20 overall) would make it a lot faster and easier to come in and out of sheath for EDU. Dedicated hunter/camping use would likely prefer the current size approx 4.5 inch/11-12 cm blade.

I'll get into the CruForge, M2 and W2 in the next few days and have them on to the next tester.

Martin
 
Last edited:
Beating on the Cruforge tonight. Again, this thing is light, 2.4 oz. As with the others I've been working them into day to day stuff where possible and this has held up fine to normal use. I would not pry anything with it, but for cutting I tried not to baby it.

This knife more than the others so far is giving me the most trouble cleanly deburring, though only compared to the 52100 and 1095. Nothing too crazy but something I noticed.

Clamped on the EI3K, it passed 124 on the first go and turned out a solid 174 on the second, best so far of those tested. I also pounded some good sized curls out of a pine board, stripped curls off some poplar. Really held up nice.

One thing I'm noticing is my numbers seem to climb on the second test somewhat reliably though I am not spending any additional time on the second sharpening. Subsurface burnishing from the test itself...? :confused:


Anyway, I wish I could think up some more testing, but on to the next.

Martin


1203151848_zpslvmyrsto.jpg
 
Martin,
Glad to see the consistency issue sorted out! :thumbup:

One question, how the weight of the knife being compensated, as I read you mentioned the CfV is very light.

Edit to add: didn't see the curl chunk until posted :eek:
 
Chris, I haven't gotten around to the weight of the tool being a factor (yet). Weight difference is about 2-3 ozs total, less of a factor than different coils or whether a splice is going through. Might have to hang a counterweight off the back for stuff like machetes or heavy build Chef's knives.
 
Martin,

You're right, seems minor in this case compared to the weight of the bell. Eliminating major factor should be the goal.
 
Alright, this is the final installment for me.

Had a go at the M2 and W2, mostly the M2. On the edge tester it made 134 and 121 passes. I noticed the streaks on the Norton 4k were substantially lighter in color with these two than the other knives, the M2/W2 at this RC was getting to be tough going for this stone. I switched to 800 grit silicon carbide wet/dry on my Washboard and the numbers went up to 186 and 160. This knife is a nice little tool, capable of fulfilling a lot of EDU chores at very low weight and looking good in the process. The wear from the test beat up the microteeth, but due to very thin grind it was still presscutting into the rope with very little force even after it had "dulled".

I used it for a bunch of regular chores around the shop, batoned through some 3/4" poplar board - hacked off good sized chunks with no issues.

Something to point out, all of these had good-fitting Kydex - no evidence of edges glancing off of rivets or scraping up on the way in or out

I put in some time with the W2, initially did not care for this one visually, but after doing some hole drilling, batoning, curl carving I came to appreciate the handle and blade configuration. The edge showed zero wear from roughly drilling through 3/4 pine or hogging off large chunks of same. Just a snap observation, but based on the way the steel along the edge held up, even for hard bushcrafting, this one could afford to be thinned out some, finished to a bright shine and it would still hold up plenty well - I took it up to 1200 wet/dry and it could have been polished further for a dedicated chop carve and shave.

Overall impressions - the designs are all more ergonomic than many, distal taper top and bottom is a nice touch, balance is good. Edge retention is plenty acceptable if not exceptional weighed against the ease of resharpening. Aside from minor tweaks to the dimensions or reshaping a contour to better fit my hand, I don't have much to add.


On to the next tester!

M2
BCMW_M2_zpsrsjegcpj.jpg


Family portrait
BCMW_Family%20photo_zpsvcprjnmq.jpg
 
Very nice! Thank you for taking the time and effort to put these through the ringer. Looks like you gave 'em a good workout.
 
Status
Not open for further replies.
Back
Top