Cutting metal hooks or wire with knife,and no damage?

Joined
Mar 2, 2014
Messages
2,569
There is many videos on youtube,where people cut bolts,wire,and other pieces of steel to test their knives.Are these tests valid,or the geometry on the blades is so thick that the blades do not take any damages in doing this?Or is it the steel,and special heat treatment?or both?Is there any knives with thin geometry that can do this?Is it just a show off?
 
They make wire cutters and bolt cutters. Even for hardened wire. If the videos aren't faked, it could be done. I don't know as much as most of the other members here. But a high wear resistance steel, good hard heat treat, coupled with the correct bevel angle would get it in my mind. The correct question is what grade of bolt? Bolts start at grade 1 and go up through at least 8, or so I have heard. Wire can be really soft too but would chip things easily because of the small size. Lots of pressure in a small area=chip. Steel, easy. Low carbon, non heat treated bar stock. Can cut it with a band saw. So a heat treated knife could be made to do it easily. I would look at who posted the video. Well known and respected maker? Probably legit. Joe bubba from redneck ville? Hmmm...
 
At work, and sometimes around the house I regularly cut copper wire and steel braid, like what you find in coax cable, with a knife.
Although I don't intentionally cut steel bolts, my blade often cuts into them. This happens when cutting through the plastic/rubber/cambric tape that insulates bolted together electric motor connections.
In over 35 years of doing this, I've found a certain family of steels (all else being equal?) that take the least amount of damage while having good edge retention in normal use. The down side is, none of them are considered "stainless".
 
At work, and sometimes around the house I regularly cut copper wire and steel braid, like what you find in coax cable, with a knife.
Although I don't intentionally cut steel bolts, my blade often cuts into them. This happens when cutting through the plastic/rubber/cambric tape that insulates bolted together electric motor connections.
In over 35 years of doing this, I've found a certain family of steels (all else being equal?) that take the least amount of damage while having good edge retention in normal use. The down side is, none of them are considered "stainless".


So, carbon steel?
 
My guess would be D2. And no way in hell could a knife with very thin geometry do that (get hammered into a steel bolt - grade 1 or otherwise) and not take any damage. Bolt cutters have a very thick geometry - probably close to 60° included - and on top of that, they aren't ground to an apex, they are ground to a flat - usually about 1/16" wide.
 
Ive done it with some of cheap knives before with really thick edge, but was wondering if some customs or more upscale factory knives could do same without damage and still shave like on videos.Or the metal is really soft!Ps.I tried it long time ago with Bark River bowie,to cut the bolt and edge was probably too thin and screwed up the edge lol.Fixed it on belt sander, but I did it with some cheap Chinese POS knife with thick edges with no problem.
 
Last edited:
This sounds like just show off stuff. It doesn't sound like a practical application or even a test that emulates any kind of hard use that someone would likely do.

I've cut 4 gauge stranded copper wire with a knife before, but I was showing off! :) Cutting that wire blunted the blade pretty badly (reflective edge after), but it didn't do any damage. I wouldn't try to cut any kind of steel with a knife unless it was some kind of emergency. Right tool for the right job.

Brian.
 
My guess would be D2. And no way in hell could a knife with very thin geometry do that (get hammered into a steel bolt - grade 1 or otherwise) and not take any damage. Bolt cutters have a very thick geometry - probably close to 60° included - and on top of that, they aren't ground to an apex, they are ground to a flat - usually about 1/16" wide.

Bob Kramer appears to do it with one of his kitchen knives (at 2:32)...

 
Last edited:
Sharpen about any knife to 50 inclusive and lightly tap with a brass hammer, you too could cut bolts in half. As long as the knife is harder than the object being cut and has proper edge geometry it should work. Although, this is nothing more than a parlor trick and proves nothing.
 
Frank Richtig did this in the 1930s or there abouts. The strength in the blade is in the width, not the thickness. Everything else being equal, a 1" x 0.075" blade will cut better (much better) than a 1" x 0.250" blade as long as you can keep it straight into the metal. A convex grind works best. Frank hauled around a wagon with axels and bolts that he had cut up with his blades (1095). He sold a lot of knives because of his parlor trick. He also made knives with some of the first cast aluminum handles.

Thicker blades have better strength when it comes to lateral or torsional forces.
 
So, carbon steel?
Somehow I never made it back to this thread, sorry.
The family of steels I refer to are high speed tool steels, m2, m3, m35, t42. The only ones presently available commercially that I know of are cpm-m4, hap40, maxamet.
For almost 20 years I used the same commercial m2 blade 0.100" thick sharpened to about 30 degrees inclusive. For about 5 years before that, I used a home made t42 blade. In that time, I've tried S*V steels, D2, 154cm, vg10, zdp189, 1095, 52100, zwear, k390, bd1, 440*, 420hc, and more I'm sure.
To make a long story sort, blade sharpening equal, the hss ones get damaged the least when contacting other metals.
Next best are the non hss, non stainless steels, with s30v being best of the stainless.
BTW, D2 from 2 different makers did not fair well at all.
 
Last edited:
Those video are useless (more like simple marketing) unless it's specified, what blade steel it is, what hardness, thickness behind edge, sharpening angle, the material being cut. Clear close up of the edge and sharpeness demo before and after.
 
Somehow I never made it back to this thread, sorry.
The family of steels I refer to are high speed tool steels, m2, m3, m35, t42. The only ones presently available commercially that I know of are cpm-m4, hap40, maxamet.
For almost 20 years I used the same commercial m2 blade 0.100" thick sharpened to about 30 degrees inclusive. For about 5 years before that, I used a home made t42 blade. In that time, I've tried S*V steels, D2, 154cm, vg10, zdp189, 1095, 52100, zwear, k390, bd1, 440*, 420hc, and more I'm sure.
To make a long story sort, blade sharpening equal, the hss ones get damaged the least when contacting other metals.
Next best are the non hss, non stainless steels, with s30v being best of the stainless.
BTW, D2 from 2 different makers did not fair well at all.
I notice you mention D2 and I have read numerous comments on how bad it is for breaking and chipping. I was curious of your thoughts on 440c
 
I notice you mention D2 and I have read numerous comments on how bad it is for breaking and chipping. I was curious of your thoughts on 440c
The reason I mention D2 was to address post #5, unacceptable edge rolling at 30 degrees incl.

Honestly, it's been so long since I used 440c, I can't give any details, but it failed either from rolling, chipping, smearing, or a combination of those. There might be present examples that do well. The closest I have to it right now is bd1, which rolls and smears too much for use at work.

I sometimes trade knives for the week with co-workers, if they have a steel/brand I haven't already tried. I give them an m2 or m4 blade for the week. They are always impressed.

Edit: Referencing the Bob Kramer video, there's a difference hammering an edge straight into a piece of steel, and drawing the edge across it, and/or putting lateral force on the edge.
 
Last edited:
Back
Top