It bent !

[Iron Hoarder]

Have you ever used the heat sink putty like the auto body guys use when they are welding thin sheet metal?

I wasn't advocating a lower Rockwell I was just making an observation. I've chipped carbide teeth on saw blades going through knots before. Any sporting use of a piece of equipment qualifies as destructive testing and will wear out, damage, or highlight any short comings of what ever is being used eventually. I thought that was the whole point of competition.

[Ropeman]

Have you ever used the heat sink putty like the auto body guys use when they are welding thin sheet metal?

I'd have thought something more compliant would be the answer. You haven't got a link to that stuff, have you? It would be very handy for some of the stuff I do

Aluminium should do the job thermally it just sounds tricky to get the heat sink right in where the heat needs to be sunk.

[fluffy]

in addition to the good customer service, i find Longstrider's first post most interesting. i guess the competition knives have a high degree of 'experimental' in them as each maker strives for the best knife for this particular job. as with any competition, technology and technique will always be the mainstay of development. fair play to Longstrider for posting his findings, as it can only help in making these knives better and better, giving the competitor the best tool for the job.

I've been to a few of these and never failed to have fun.
As for competition: been there. done that.
Not what drives me with this: I spent two years of comps cutting left handed just to get the feel for it.

I've used:
The top two here by Colin in L6


This Valientco Golok in spring steel


This 20 minute knife by Mike Blue


and a few khukuris


before the one that bent on Friday.

Mikes snapped a chink out on hitting (well, whaling through really) a large knot, which taught me to avoid knots. To be fair it was on the side of the wood away from me so I hadn't looked for it.
The grain was too big in the steel and those in the know reckoned the 20 minute rule had led to less than perfect HT which made it too hard.

The Valientco, despite having the handle paracord wrapped and supaglued, had the handle crack chopping 2x4 and the blade chipped.
lovely garden knife but not a fit steel for repeated attempts at wood.
TBH it had excellent garden use for years on brush.

the khuks are not the best shape for the job and are a bit soft.

I'll buy a Farid in D3 next because the D6 flatground bushy is such a great tool and a local maker can be nagged

I'll get another off Ian after I've tested that at another comp.

Between the two we can be assured of quality and UK (non VAT) service BUT there are nice knives made elsewhere and the goodwill will be best served by such displays of immediate attention to problems and exploration in the open on the forum like this.

[ANDYLASER]

Excellent response Ian. It is good that a full investigation not only revealed the problem, but also how to fix it.
Well done.

[Iron Hoarder]

This is just one kind. There are several and some are a gel, a paste, or clay. It's best to read up on them. See if you can find a good local auto body guy that uses metal instead of slinging mud or a professional close tolerance welder for what is available here in the UK.

http://www.eastwood.com/ew-anti-heat-compound-1-qt.html

[rojaz]

I'd have thought something more compliant would be the answer. You haven't got a link to that stuff, have you? It would be very handy for some of the stuff I do

Good stuff in the UK is called 'cold front' and sold by Frosts....
http://www.frost.co.uk/automotive-we...ont-414ml.html

[John N]

not to worry mate! quite often its not how you spill the milk its how you clean it up

Im sure there are some real heat treat howlers out there that never see the light of day as the knives arent used hard.

Ive got a lot of time for your methodical methods getting to know one kind of steel well, and optimise what can be done with it (to the point that if I was going to commision a knife as a spot on dependable user I would give you a shout first). Your fit and finish on the last ones of yours I saw aint half bad either

[Miles Undercut]

Many thanks for the valuable information. I see this problem of how get enough heat into the blade and guard to get a good solder joint, but without de-tempering the blade, mentioned-- but then side-stepped or glazed over-- in magazines and books again and again.
I've been gathering courage to confront it. This will help.

[Stew]

Should have used a cucumber Ian.

[Longstrider]

Just to answer a few points raised since I last looked in ...

If you have a knot in your section of 2x4 you can opt to cut it a little further along in order to avoid the knot ... as long as you are still cutting between the bench and the taped section at the end of the wood. The danger of getting too close to the bench is that you just might hit it of course.

In this case using copper as a heat sink would have had no advantage over the aluminium I actually used. This is simply because I stupidly didn't have then ruddy heat sink against the bevels of the knife I had thick, flat plates of ally clamped to the blade, which had a very high sabre grind almost to the point of being full flat, but not quite. The clamp was at the top.. and the plates consequently only touched on the narrow flats above the bevels. This allowed the heat to travel through the very narrow ricasso and into the bevels and the edge.
I'm going to be exploring this heat sink putty stuff, Never heard of it before but it sounds like an almost perfect solution to the problem if it's up to the job.

Stew .. have used a spud before now on a non-knife project with similar associated problems and it worked a treat. I just thought the ally plates was a far more 'knifemaker' solution to the problem and less messy (and less smelly). Should have known that trying to be flash would always lead to problems for me. I'm usually far more at home with a smelly old fashioned style approach to a problem than anything that might even vaguely resemble techerMc-nology

[Stew]

Stew .. have used a spud before now on a non-knife project with similar associated problems and it worked a treat. I just thought the ally plates was a far more 'knifemaker' solution to the problem and less messy (and less smelly). Should have known that trying to be flash would always lead to problems for me. I'm usually far more at home with a smelly old fashioned style approach to a problem than anything that might even vaguely resemble techerMc-nology

It's actually one of the earliest things i remember being discussed on BB when I joined.

[jameswood]

well done Ian!

cant even laugh at you now you've said that

[mojofilter]

Admirable product backup Ian, not many would refund a knife that the edge rolled a little on while chopping knotty wood!

[AndyW]

Great to see this issue not only resolved so efficiently at the time but to hear how it's been investigated so promptly, openly reviewed and discussed so amicably in this thread!

Nice one Ian.

Andy

[Longstrider]

Mojo ... It wasn't an edge roll in the typical sense, or by a little ! About a 12mm section of the edge, going back into the bevels by about 6mm was bent out of alignment with the rest of the knife ! It was, in my opinion, caused by Johns determination to work either through or very closely around a rather stubborn knot in the wood (NOT blaming John at all) The knife stuck in it a couple of times then glanced off it at a hell of a lick. The damage could be considered as 'one of those things' by some I suppose, but it's NOT what I expect to see on one of my knives. Not only did I not want Fluffy to be stuck with it, I wanted it back to see if I could find out what the hell had caused it to deform in such a manner. I've never had a knife fail on a 2x4 previously and I'm determined to do all I can to ensure it never happens again. Now that I am happy that I know the cause of the problem I can continue, happy in the knowledge that I can avoid it ever happening to me again.