Zach, I really like L6 for toughness and edge-retention and think it would perform very well for the task at hand, but it will stain and rust if not cared for properly. Same goes for 5160, 1070, and frankly most of the other steels commonly used by bladesmiths for big choppers.

How critical is stain resistance to your customer? Would he be willing to compromise toughness and edge retention for stain resistance?

I have always been a big proponent of using the steel that you are most confident in H/T'ing. If that is a simple high carbon steel just let the buyer know how to care for it.

Gary

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Zach, I really like L6 for toughness and edge-retention and think it would perform very well for the task at hand, but it will stain and rust if not cared for properly. Same goes for 5160, 1070, and frankly most of the other steels commonly used by bladesmiths for big choppers.

How critical is stain resistance to your customer? Would he be willing to compromise toughness and edge retention for stain resistance?

he stressed that it's very important to him for the blade not to rust up. i told him it wil patina up some, and that will give it a better resistance. his reasoning is that when customers see a rusty blade that its off putting. especially when some of it flakes off into their coconut. of course he doesn't want it oiled when using it all day because it will get in the coconut.

i know nothing of bluing, but was going to look into it to see if it would be a viable option.

the other tool looks similar to an apple corer, so it can make a hole in a coconut for the straw to go in. i figured i could forge that pretty easy.

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I have always been a big proponent of using the steel that you are most confident in H/T'ing. If that is a simple high carbon steel just let the buyer know how to care for it.

Gary

thats part of my line of thought, but if there is a better choice of steel to make and i fail some test pieces on heat treating i have no problem out sourcing it until i learn that particular metals quirks.

The customer is requesting some type of steel that can handle chopping up coconuts all day, have edge retention, and not rust up in the sugar water.

This is one of those situations that many buyers/knife users simply cannot wrap their heads around. Most everything we do in producing a knife is a trade off. There's not a problem building a blade that will chop coconuts, and have great edge retention. The problem comes in when you want a blade to do those things AND not rust or tarnish. Obviously the thought pattern of stain resistance takes you to a stainless steel, which is going to give you the rust/tarnish resistance, but then you're going to run into problems with the "chopping" portion of the equation.

Stainless is a whole differnt ball of wax versus carbon/alloy steels. With carbon/alloy steels you can "adjust" the level of hardness somewhat, to help mitigate the less desired qualities, but when it comes to most stainless steels, they have a very specific target hardeness where they will cut well and have decent edge retention....getting just a couple of Rc points either way of that target hardness, and performance takes a nose dive, either from the steel being too brittle/chippy, or the edge deforming from being too soft.......another "trade off" to deal with.

Another trade off that is common with stainless steels is that at their "target" hardness level, they are far more difficult to resharpen then a carbon/alloy steel. An example of this....just a few short years ago, CPM S30V was all the rage and in high demand....while it held a great edge, almost no customer was capable of resharpening it themselves (and eventually any blade is going to require resharpening) I made a number of knives with that steel, and routinely have customers send them back to me to resharpen....because the "target" hardness level makes the blades VERY difficult for the average knife user to resharpen.

Were it me, I would tell the client that a decison nust be made.....chopping and edge retention, or stainless qualities.....which is more important? Based on the answer to that question, my decision for a steel type would be made. Personally, when someone says "chopper", I encourage using 5160 steel, because it is very forgiving, and is probably the "easiest" steel for producing a great cutting/chopping blade. (theres a reason why more JS tests have been passed using 5160 then any other steel) but with it, you throw stain resistance right out the window. In a nutshel, my opinion is that the customer is going to have to give up one of the qualities they requested, and be prepared to live with the consequences....this is a situation where I feel you're not going to be able to achieve everything the customer wants....at least not to the levels they are likely expecting.

Ed is absolutely spot on in his reply. And this is something that comes up quite regularly for custom knifemakers. Some customers, in their search for the perfect knife, will come to a bladesmith and request their own Excalibur - a blade that can chop through steel and concrete, flex 90 degrees, never break, maintain a perfect edge, shave hair, never rust, and glow in the presence of orcs. It is up to us as knifemakers not only to make the best knives we can for our customers, but also to educate them about the product they are buying - including its practical and metallurgical limitations.

In your specific case I would recommend explaining the trade-offs between stain resistance and cutting/chopping performance, and perhaps suggest (as you already mentioned) a blued carbon-steel blade. The bluing will help prevent some surface oxidation, but will still require some care and maintenance - as any quality tool would.

In terms of bluing techniques, you can find a lot of good information online and there are a few bladesmiths who regularly use bluing with great success on their forged carbon steel blades (Jason Knight comes to mind). Check out some of the products by Birchwood Casey and KG Industries and simply follow the instructions provided.

Thank you to all of you who have replied. the trade-off conversation is one that i touched on with him. i will see him this week and ask him whats more important to him and what those trade offs will be.

Thank you all, once again!

Sorry I'm a little late responding to this but thought I'd weigh in. I'm curious as to what you and your client settled on. Keep us posted.

I agree with Ed, Derrick and Gary. They gave you great advice.

Regarding the bluing, I would have some reservations about it....at least cold bluing. I've never achieved a good lasting finish with it and would be concerned that it would come off fairly quickly and easily. I'm no pro with it and doesn't mean others haven't had success with it. The other concern I would have with it is the toxicity of it. It is nasty stuff. Smells nasty and is poison if you ingest it. I wouldn't want any of that making its way into food items. Probably more toxic than some of the rust preventive oils. Though, on the other hand, it may lose that toxicity when properly applied, neutralized and cured. I've just never had good luck with it.

If as Ed mentioned, stain resistance is the priority, you will likely have to go to some sort of stainless steel. Otherwise, if chopping and edge holding is the goal, I would personally opt for 1075. That steel is very tough and takes and holds a good edge. You could force the patina on it to begin with which will help inhibit rust.

Further, food grade mineral oil can be used for maintenance. It will prevent rust and be food safe.

Thank you all. I am thinking i want to either use 15n20 or one of the 10xx series i'm used to working with.

I explained the variables to him, and he said its up to me since he doesn't know about metal, he knows coconuts and poker... heh.

thanks again guys.