Blade Steel Rehardening

Gator97 said:
Sux... There's no way to adjust all that with pivot screw?
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Not that I know because the way Mnandis work require the the pivot screw to be tightened all the way. He said I could shim the stop pin but I tried and was unsuccessful and didn't want to take too much off. I'm going to see what CRK tells me.
 
Yeah, CRK folders probably are not a very good choice to be messing with something like this. If I remember correctly someone was putting a blade coating on Sabenzas a few years back and that also didn't work out so well. I for the most part disagree with what Phill has posted but I guess I'd let his last post slide, at least for that one. :) Was just the blade sent in or was the knife it self sent?
 
Does it use a bushing like the Seb? If so, I'm guessing a couple thousandths need to come off so the frame closes in more on the slimmer (buffed down) blade.
 
I think somebody should try something like a Buck Vantage Pro or S30V Leek blem from kershawguy blem some other cheap knife with S30V that is readily available. That way he can re HT the blade (washers aren't as much of a worry as bushings are for changes in tolerances) and we can see what he can really do. If it doesn't work, it's under $50 loss and not $400, I think it would be worth a try. I don't have any money right now to contribute to buying one for experimenting purposes but I want to throw the idea out there.
 
SteelSnob said:
He said I could shim the stop pin but I tried and was unsuccessful and didn't want to take too much off. I'm going to see what CRK tells me.
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Shimming implies adding material, not removing it. This post concerned me.
 
SteelSnob did you only send the blade to cotdt or was the hole knife sent to him?
 
Lucky Bob and others.... I do not consider my heat treatment processes novel. Everything I do pretty much comes from the steel company data sheets. The basic method to get a higher as quenched hardness is to go to a higher temp for the initial heat cycle. The production companies mentioned here have good reasons for their finished hardness targets. They are shooting for a good balance between hardness and toughness. They are shooting to satisfy 98% of their users. Ductility and corrosion resistance as a couple of examples can be compromised at a higher hardness. None of them want a chipped or broken blade back and then to have to replace or repair the knife. I do a few re-heat treats once in a while if I can work it while I am heat treating my own blades. I try to make sure those requesting this work understand the risk.
The warranty on the knife is voided.
Tollerances may change and there could be trouble with a folder fitting up.
Increase hardness will always increase the wear resistance but will also decrease the ductility.
There will be some dis coloration on the blade and it could be very hard to remove.
Both myself and the person requesting the work are at risk. I have had a couple of blades crack due to uneven grinds and thick portions next to thin areas. I have had mistaken steel grades that do not heat treat as specified and have to do them over.
The blade manufacturer may not appreciate me changing his original work. I discussed this with Sal (Spyderco) at the Oregon show last year and he is ok with it but there may be others who could have concerns. It's kind of like having a rifle sent off to accurize it or a aftermarket modification to a car engine like adding a chip ect.
I mostly stay with the CPM steels since the grain structure is very fine and it would be hard to "blow" the grains on these steels by a little over heat or too much time at heat. I do a hardness test at every step to make sure things are going as planned. I do charge for this service since it does take time away from my own custom knife work.
So why do I even mess with this? I have considered quitting this altogether. The main reason is I like to see improved performance for those who are striving for it. I also get good feedback on how the blades perform and this helps me calibrate my own work. I think for some of those like Gun Mike and Gator who are willing to take some risk and clearly understand the process we can work together to push the envelope a little. For others it is probably not worth the risk, expense and trouble to mess with something that already works pretty well. Maybe this puts some of the previous discussion in perspective.... Since I saw my name come up thought I would jump in.. Phil
 
Great reponse, Phil. I'll drop you a line soon, I've been laid up in a hospital for the last 3 days with severe pnuemonia. I would love to see what you can do with my S90V Manix 2, and as you said I am fully aware I may end up with an unuseable blade. I have a feeling what I'm really going to see is a blade with much improved wear resistance. I can't wait to see what you can do with M4, either. I am extremely impressed with what Spyderco and Tom Krein did with CPM M4 at 62.5 RC, but I am pre-ordered for 2 Spyderco folders in CPM M4 that are coming out next year, it may be interesting to see what CPM M4 does at 64-65 RC. Thanks for your input here Phil, and huge thanks to cotdt for offering this service for no cost. I know I for one really appreciate it.

Mike
 
so i got two blades back from cotdt today...both were 13c26.....sharpened one blade up.....not fully polished.....i was going to quick and rushing a little.....it was definately harder to sharpen....meaning wearing away less than usual....so it does seem harder.....time will tell though.....ryan

p.s-thanks alot for this service-should be interesting to test it for sure:thumbup:
 
Hard Heart, CPM S125 at 62/63 should be just right. It can be pushed to 64 or a little more with no problem. I still have a little left and maybe when the time is right will tackle it again. I just got some CPM M4 and will be seeing what I can do with it. Also have found that CPM S110v at full hardness (64) is equal or mabybe a little better that S125V. A tad tougher but do loose some corrosion resistance due tol the high temp temper cycle.. Phil
 
Phil, that CPM S110V at full hardness sounds like wonderful stuff. I can't wait to see what you can do with CPM M4. At 62.5 RC it is really impressive stuff with great sharpness, very good edge retention, and excellent toughness for such a wear resistant steel. As expected corrosion resistance isn't a strength, but the trade off is worth it IMO due to the great performance. I would love to see what CPM M4 does at 64-65 RC.

Mike
 
gunmike1 said:
Phil, that CPM S110V at full hardness sounds like wonderful stuff. I can't wait to see what you can do with CPM M4. At 62.5 RC it is really impressive stuff with great sharpness, very good edge retention, and excellent toughness for such a wear resistant steel. As expected corrosion resistance isn't a strength, but the trade off is worth it IMO due to the great performance. I would love to see what CPM M4 does at 64-65 RC.

Mike
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I admit to being very spoiled living in a dry climate. Corrosion resistance doesn't even enter my mind in terms of a trait that I look for in a steel. It sounds like we'll have to do some testing on CPM M4 and CPM S110V if you can ever get your hands on them at full hardness. Or what we would consider full hardness... ;)
 
sodak said:
I admit to being very spoiled living in a dry climate. Corrosion resistance doesn't even enter my mind in terms of a trait that I look for in a steel. It sounds like we'll have to do some testing on CPM M4 and CPM S110V if you can ever get your hands on them at full hardness. Or what we would consider full hardness... ;)
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Tempering is for sissies right, as quenched hardness or bust for us Sodak! Seriously, we are the types that like to see what the upper end of hardness and thinness can do for a cutting tool. I don't have to worry about corrosion too much either, but a buddy washed off my M4 Mule after gutting the piggy I got and didn't bother drying it off much before sheathing it leaving some surface rust. No biggie, it's a working knife anyway that I think needs a regrind to under .010" to bring it to it's full potential anyway. CPM M4 sure is a marvel. You have to play with yours to see what I'm talking about, assuming it is near the 62.5 RC of mine (Spyderco listed 57-62 as the hardness range for some reason, though everyone I've heard from reports their M4 Mules to be on the hard side). CPM M4 gets so sharp it is amazing, I just can't wait to see it at 65 RC to see if it is better than the already great performance at 62.5 RC or if more hardness is too much of a good thing with it.

Mike
 
A_Blade_Afficionado said:
I think somebody should try something like a Buck Vantage Pro or S30V Leek blem from kershawguy blem some other cheap knife with S30V that is readily available. That way he can re HT the blade (washers aren't as much of a worry as bushings are for changes in tolerances) and we can see what he can really do. If it doesn't work, it's under $50 loss and not $400, I think it would be worth a try. I don't have any money right now to contribute to buying one for experimenting purposes but I want to throw the idea out there.
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Actually I've done both my own Vantage Pro and a friend's Kershaw Leek. Both turned out well. The main issue I have is that some of the blades have an ever-so-slight amount of blade warp. I can correct it down to under 0.3 mm so that it isn't noticible but can never completely get rid of it when it does happen. So it should be a knife a person is willing to risk.

ryan9977 said:
so i got two blades back from cotdt today...both were 13c26.....sharpened one blade up.....not fully polished.....i was going to quick and rushing a little.....it was definately harder to sharpen....meaning wearing away less than usual....so it does seem harder.....time will tell though.....ryan

p.s-thanks alot for this service-should be interesting to test it for sure:thumbup:
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Yeah it gets harder to sharpen when it's rehardened. So I take it you managed to fit the blades back into the folder? Did you notice less burr formation when resharpening as compared to stock 13C26?

It's great to see Mr. Wilson chime in and hearing about others' results with rehardened blades. There are still a lot of steels that I've yet to try like S35VN and some of the exotics (70 rc CPM121 anyone?).
 
I'm not sure where to put this but figured a few that might check this thread might be interested.

I opened up my M4 Benchmade Rift the other day and noticed somehow the very tip was damaged and the steel was bent over. I don't remember doing anything that would have damaged it, but it was folded over instead of being chipped off. I took a steel to try and straighten it out and I'm not sure if it did or if it broke off but now the very tip is blunted a little. I'm talking very small though like 0.010" maybe less, so I'm sure it will sharpen out eventually.

I guess I figured if it was over 60rc that it would have chipped and I was hoping this was at least 61rc. But maybe it would roll even at a higher hardness?
 
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