Some Surpises Cutting Cardboard w/ the Delica

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me2

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Oct 11, 2003
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Just thought I'd get some opinions here. I was breaking down some boxes and used my Spyderco Delica to cut them. When I was done, the edge had small chips in it and would barely slice paper. Any ideas on what happened? The cardboard is the kind in department store clothes boxes. Its like cereal box cardboard, but a little thicker. The edge on the Delica is not new. I've had this knife for 18 to 20 months now and have rebeveled it to 17 degrees with a micro bevel of 20 degrees on the Sharpmaker. I've never seen this happen to it before. My Griptillian did the same thing. After resharpening, it has cut through about 760 inches of aluminum sheet in can form with no problems. I'll resharpen the Delica tomorrow night and see if it keeps happening.
 
recycled cardboard (the kind used for anything NON-food related) can have bits of metal in it due to being thrown in with tin cans and what not during the recycling process.


Edit to add: its POSSIBLE you got a fualty heat treat as well they do happen now and again. you can test this by placing the side of the edge flat on the table like you would when sharpening, and then push pretty hard while keeping the spine off the table. If the HT was fualty the edge will chip abit and you should send it to spyderco if it doesnt chip then its probably fine and there was somthing in the cardboard.
 
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I cut cardboard all the time, mainly from Costco grocery shopping or shipping boxes, and I have not chipped any edges yet. What blade steel do you have on the Delica?
 
Cardboard will kill an edge no matter the steel. If you had a perfect edge before you started cutting cardboard, you'll have a pretty dull edge (by my standards) after the first few cuts.

As far as the micro-chipping: I get that with ZDP-189. It happens not as bad sometimes with VG-10, but after a couple sharpenings I think it stops doing that so much.
 
I'm gussing your delica is VG-10? VG-10 is a good steel but against cardboard your results are what I would consider normal. Cardboard can also very greatly, I've had recycled cardboard the could dull 1095 within 6 inches and S30V in 30 inches. Cardboard will also hold dirt in its surface and that makes it like cutting sandpaper. For cutting cardboard a high wear resistant steel like S30V or better would be ideal.
 
Gen 3 or 4? Which steel? I haven't seen this with mine (Gen 3 in VG 10 and Gen 4 in ZDP), but am interested to see what you find.
 
Its a generation 4 version, with VG-10. This knife has been used pretty heavily before and sharpened a lot. I've cut aluminum cans, I think I've done a cardboard test on it before. My old Delica, a generation 3, never had this problem. I've used this knife for some nasty scraping, which did some damage, but that was scraping steel. That damage was sharpened out, but perhaps left some unseen/unremoved weakened or damaged metal. Thats the best explanation I've got. I've cut cardboard with lots of knives. I've found that a hair shaving edge typically stays longer than most people expect, even for "cheap" steels like whatever Kershaw uses on the Vapor series.
 
me2 said:
I've found that a hair shaving edge typically stays longer than most people expect, even for "cheap" steels like whatever Kershaw uses on the Vapor series.
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Have found that even a lowly steel like 420HC, when sharpened correctly will hold an edge just fine for most of my uses. It will need more touching up than "super steels," but that's all good because even my super steels hit the ultra fine stone and a strop before they go into my pocket. :cool:
 
Greetings: The following is only my opinion. Cardboard cutting seems to cause micro serrations on many blades. The varying density and diameter of the fibers and other material that make up the cardboard can grab a very minor imperfection on a slightly toothy edge and create a micro chip. As the cut continues, more fibers can lodge in the micro chip and break off adjacent pieces of the edge. I cut A LOT of cardboard. As Knifenut1013 pointed out, recycled cardboard is the worst. Polishing the edge seems to help greatly in reducing cardboard micro-chipping. Unless a polished edge of at least 30 degrees with a micro bevel of at least 35to 40 degrees is used, the edge just doesn't hold up for me. Of the eight knives I have in S30v only the UK PenKnife appears to exhibit edge holding that is close to S90v in resisting the micro-chipping of recycled cardboard on an unstropped edge. OldDude1
 
me2 i cut cardboard all the time & do'nt get the chipping.i test my knives on 275 lb. burst strength boxes. double thick like 2 pieces glued together.the guys do have a point about the recycled stuff having lots of trash in it. when i check the boxes from prochem i'll let you know if it says recycled.
 
Only the Grip and the Delica have shown chipping during cardboard cutting. I did it with a knife made from M2 at over 64 HRc and a 12 degree edge with no chipping and filled 2 trash bags with cut up bits of cardboard. It must be the damage from scraping the pipes a couple of months ago. I have only given it a real metal removing, burr forming, sharpening session once since that day. Come to thing of it, the Grip was used for scraping paint off a steel tank prior to the chipping. I think this is whats known as a pattern;). I'll give the Delica a full metal removal sharpening again this weekend and see how it turns out. I've given the Grip 2 or 3 full sharpenings since the tank scraping. Its doing fine now. See my extended edge holding thread for more info on the Grip cutting aluminum cans and defying my attempts to dull it. No chipping either so far.
 
I'm surprised to see this with VG 10. Unfortunately, I don't have an exact match to compare to, I've got gen 3 in VG 10, and gen 4 in ZDP. But I do have Caly 3's and Jr.s, and haven't noticed this in any of them.

The cardboard you are describing almost sounds like paperboard. Does it chip cutting "wafflely" cardboard? If so, then I'd guess you still have weak metal from the scraping, or have some recycled cardboard (as others suspect), or both.
 
We buy knives to use em. We buy sharpeners to sharpen them.
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And if you cut up boxes for a living you use a boxcutter. It's the right knife for the job.

tipoc
 
tipoc said:
And if you cut up boxes for a living you use a boxcutter. It's the right knife for the job.

tipoc
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If you say so. Because if you ask me, any time I have to use a box cutter, I think, "Damn, I could have been using my knife for this..."
 
I've been using a re-beveled Delica 4 to cut down cardboard for recycling for a couple months now. The edge is fully polished and I also smoothed out the ridge between the primary and secondary edges to minimize cutting resistance. So far, I've not seen any chipping although it dulls fairly quickly as you would expect.

I enjoy using the Delica over a boxcutter. :)
 
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