Is a 2mm thick cutting comp knife totally stupid?

[Stew]

Doing some bits at work and may have bought too much 2mm O1. :rolleyes:

I had a piece bigger than 15" x 2" so while the angle grinder was still out, I cut it down to size then when I got home got the bench grinder out and gave it the most basic of profiles and started the bevels.

Seems like it would be quite quick in the hand as it's so light weight but will it just get destroyed if it was cutting 2 x 4?

I left the blade 2" wide for all it's width (just giving it a point) to try keep it rigid.

Even unheattreated with a blunt edge it was chopping quite well (beating it's way through!)

Is this just madness?

[MushiSushi]

Is this just madness?


not necessarily, you've lost the weight, which is useful. but you've reduced the drag/friction and made a "quicker" blade. For the same reason that you can't swing a tennis racquet as fast as you can swing a badminton racquet. Fastest recorded shuttle speed in badminton is around 200mph which is nearly 50mph faster than the fastest tennis serve.

[Colin KC]

No Stew, it's quite a departure, but not a bad thing (though only a comp will tell;))

[mrmcc]

If you look at the sami knives used by the reindeer herders in northern scandinavia they are made from very thin stock and perform really well,they are carried by both men and women and used for everything from cooking to chopping down trees,the most popular prodocer is Stromeng.
MM.

[Albert E]

I think you will have a great knife!!Please show the results!!
Albert

[RIKARDPHOTO]

i agree with the point about the sami knives... compared to them being 9" blades - they're only 2-3mm thick and very easy to handle because of that.

Meself not being super experienced in making my own blades, I think I would start by making it at least 6 cm at the widest and around 3,5 at the bolster...

Let's see it when done - go on:)

Anders

[MushiSushi]

I think I would start by making it at least 6 cm at the widest and around 3,5 at the bolster...

if you are going to follow the rules strictly, then 5cm (2") is the maximum depth of blade allowed (although we rarely follow rules in our comps ;) )

[RIKARDPHOTO]

Ahhhh cheers Simon, wasn't aware that there where specific rules for the knife dimensions other then lenght.

Got any link to these rules? Would like to read them.

Cutting Comp's arent big in Denmark:)


Anders

[fluffy]

Ahhhh cheers Simon, wasn't aware that there where specific rules for the knife dimensions other then lenght.

Got any link to these rules? Would like to read them.

Cutting Comp's arent big in Denmark:)


Anders

http://www.britishblades.com/forums/showthread.php?t=58896&highlight=cutting+comp

[Knife-Man]

I think a thin knife is a good idea although Im yet to test my theory.

Although I wouldnt have gone as far as 2mm :O .

[ZDP-189]

It would make a good bolo/ bamboo cutter, if maybe not the ideal compo knife.

Let me know if you have spare stock to sell; it'd save me grinding down from thicker stock.

[Stew]

Although I wouldnt have gone as far as 2mm :O .

It was only as it was sat there - I figured I may as well!



Let me know if you have spare stock to sell; it'd save me grinding down from thicker stock.

What dimensions are you after Dan?

The sheets that I bought are 2mm x 100mm x 500mm & cost approx £12. I can pick another up for you and post it over if you like?

[Hattie]

in addition to the items pointed out above (less weight etc.), think you will find that a differential or soft temper is rather essential to help keep the blade from breaking at 2mm thickness. having said that, you will also have to make due with the possibility that it may bend easily and may not be straight after hard use. also soft knives lose their edge quickly, but can be sharpened quickly too.
The only chopper i ever had break chopping was a Kershaw D2 (poor choice of steel if you don't know 100% what you are doing in the heat treatment) Outcast chopper which supposedly was hardened to a pretty soft 54-56 rockwell. and that with a 4.5mm spine and 2mm at the edge. It was replaced by Kershaw - unfortunately without comment by either the designer Ken Onion or Kershaw. possibly improperly tempered. Needless to say i now trust other knives (including my flea market south american parang) for chopping tasks.
Note that a typical south american machete has thicknesses from 2mm or less down to a bit above 1mm and i never have seen a broken one.
there is definitely something to the statement: 'it's all in the heat treatment'

life is a compromise 8)

[Winter]

If it works, it isn't stupid. :)

[Longstrider]

I'd have thought that 2mm would make for an extremely 'fast' blade Stew, but I'd have reservations about 'having at' a 2x4 with it in any serious fashion myself. I've seen much thicker blades bend due to the forces involved in cutting the wood. The grain tends to want to turn a light blade to it's own direction towards the end of the cut. This sudden slight twist leaves the blade tip still trying to travel downwards with all the force of the swing, but the knife is suddenly at a much flatter angle than it was, making the blade bend under the inertia of it's own top-end.
A 2mm thick cutter would probaly make an awsome bottle chopper, and would do well with things like the postal tube, straw, and paper cutting. I think it would fall down due to lack of inertia on things like the bundled rope, multiple water-filled 2 litre bottles and 2x4. Not sure of the outcome of getting nasty towards a golf ball or anything else made of something hard though.
It would be very interesting to see just how well it fared in a full-on competition. Any chance of you finishing it up and getting up to the next cutting day at Owens ?

I'm headed the other way at the moment, trying to decide whether to set about a piece of 6mm stock on my next set of days off, or risk the 8mm :O

I've posted a few bits about knives for cutting comps on the thread Fluffy has posted a link to. We don't always stick to knives 'in spec' at the moment, mainly because a few of the guys who cut simply don't have the right knife for the job yet. I'm hoping that in fairly short order we can get around to all using 10-2-15 knives, if for no other reason than that of parity with the cutters in the U.S. so we can more closely compare results. Any BladeSports UK records that might be set, would have to be done with an 'in spec' knife though, and no-one would ever be allowed to cut with a knife we honestly thought was unsafe for the job.

[Stew]

This sudden slight twist leaves the blade tip still trying to travel downwards with all the force of the swing, but the knife is suddenly at a much flatter angle than it was, making the blade bend under the inertia of it's own top-end.

Yeah, sounds reasonable. I've left it 2" wide for most of it's length to try keep it more stable. It's not like I need to cut down on the weight!! :lol:


I'm headed the other way at the moment, trying to decide whether to set about a piece of 6mm stock on my next set of days off, or risk the 8mm :O


Oh, I have one of those in progress as well (thik it's 8mm) but it's a lot more metal to remove so is taking a while. (Started last year!)

[Stew]

http://img.photobucket.com/albums/v140/sjlight/MrSkinny.jpg

[Stew]

Any chance of you finishing it up and getting up to the next cutting day at Owens ?



Forgot to ask before - is there a day planned yet?

No rush for me as I need to get things done but if it's a way off I may be able to block the date off so I can attend!

[Inspector71]

No Stew, it's quite a departure, but not a bad thing (though only a comp will tell;))

Agreed - make it and try it :)

I've been thinking about similar myself. Shouldn't present many probelms if the edge geometry is good.

[Stew]

Well, it survived the hot-cold-hot process (which is nice considering the quench occurred at approx 6:15am and the temper wasn't until about 4:30pm :X )

I shall get it sharp and cord wrap the handle so I can try it out before investing too much time in it.

I'm going to 'have at' some lumps of wood and I think I'll film it. :lol:

http://img.photobucket.com/albums/v140/sjlight/IMG_1359.jpg

http://img.photobucket.com/albums/v140/sjlight/IMG_1358.jpg

[Stew]

It was raining quite a bit today o no filming but a quick picture.

It chopped this piece of fallen hazel without any rolls or chips so I'm happy to put a handle on it so I can use it properly.

http://img.photobucket.com/albums/v140/sjlight/DSC00860.jpg

[Stuart Ackerman]

I have a few metres of M2, in 30mm x 1.5mm thickness...it would probably break long before O1, especially if it was as hard as M2 is capable of...tempering down might be an answer for me, maybe...especially if used for HARD chopping...

[Longstrider]

Looking good Stew :) . Get a handle on it and drag yourself down to Owens (http://www.britishblades.com/forums/showthread.php?t=63701) later in the month so we can see how it fares ! Do it ! ;)

[case]

ive got some bandsaw blade thats 250mm wide .its only 2mm thick and it works all day long ripping down huge logs so hacking a 4 by 2 shouldnt worry it.youd only want a short steep grind ,id say.
pix please.
cheers casey

[Stew]

Looking good Stew :) . Get a handle on it and drag yourself down to Owens (http://www.britishblades.com/forums/showthread.php?t=63701) later in the month so we can see how it fares ! Do it ! ;)

Handle will be going on asap. I rushed the cord wrap it started slipping in use so I removed it. 2mm is really uite uncomfortable on the hand. :D

Not sure if I'll be able to make Owen's yet. :X

[Stew]

Looking good Stew :) . Get a handle on it and drag yourself down to Owens (http://www.britishblades.com/forums/showthread.php?t=63701) later in the month so we can see how it fares ! Do it ! ;)

Handle will be going on asap. I rushed the cord wrap it started slipping in use so I removed it. 2mm is really quite uncomfortable on the hand. :D

Not sure if I'll be able to make Owen's yet. :X

[Stew]

ive got some bandsaw blade thats 250mm wide .its only 2mm thick and it works all day long ripping down huge logs so hacking a 4 by 2 shouldnt worry it.youd only want a short steep grind ,id say.
pix please.
cheers casey

Surely that's quite a different situation though?

[Stew]

Finally got a handle put on this before work this morning.

http://img.photobucket.com/albums/v140/sjlight/DSC01670.jpg

I think the dog is impressed!

Now to break it......

[fluffy]

Are you coming to Blades Uk 2009 with it ?

[Stew]

Are you coming to Blades Uk 2009 with it ?

I doubt I'll be attending.

[Alfie]

wel, if it struggles on the 2x4s, it'll still be a fine kitchen knife!

[Shinken]

Yeah i think it would struggle too.

I think your better of having a thick spine with a full flat grind (maybe slightly convex) right to the spine. That way you get thin blade with weight also