Do I need Diamond Stones to Sharpen Magnacut Steel?

D

DavidABQ

Joined
Jul 31, 2017
Messages
1,429
I have been using
Spyderco ceramic stones with a fair amount of success but that was with stylings like S30, S35, ATS34 etc. I can't seem to sharpen the Magnacut steel blade on my Buck 501. Do I need to switch to diamond stones? What options do I have when sharpening some of these new steels?

Thank you.
 
If you can sharpen S30V, I'd be surprised that you're not having success with MagnaCut...but diamonds (and CBN), are an excellent addition to your sharpening arsenal, and there are many reasonable options within that realm.
 
Looking at the composition of Magnacut, it shows vanadium at 4%. There's sort of a thumb rule that any alloy with more than 3% vanadium would be better handled with either diamond or cbn, especially at finer finishing grit sizes as the size of the vanadium carbides will begin to influence how well the abrasive can refine them. At coarser grit for setting bevels & such, you might be OK with something like SiC or good quality aluminum oxide stones.

I haven't tried Magnacut. But I've found that a steel like S30V with its 4% vanadium responds much, much better to finishing with diamond, as compared to using something like alumina ceramics. Easier grinding, refining and polishing - makes a night & day difference when using diamond for these steels. Whether it's actually needed or not is somewhat subjective. But I know I was much happier with results obtained on diamond when sharpening S30V in particular.
 
Last edited:
Blues said:
If you can sharpen S30V, I'd be surprised that you're not having success with MagnaCut...but diamonds (and CBN), are an excellent addition to your sharpening arsenal, and there are many reasonable options within that realm.
Click to expand...
I am baffled as well! Both knives, Magnacut and S30, are Buck model 501s. I have a course DMT diamond plate that cuts it easily but when I move to my Spyderco stones to smooth out the edge a bit seems to dull the edge.
You are correct. Adding a medium and fine diamond plate is worthwhile.
 
DavidABQ said:
I am baffled as well! Both knives, Magnacut and S30, are Buck model 501s. I have a course DMT diamond plate that cuts it easily but when I move to my Spyderco stones to smooth out the edge a bit seems to dull the edge.
You are correct. Adding a medium and fine diamond plate is worthwhile.
Click to expand...
That's exactly what I noticed when I was trying to use ceramics to refine S30V. They tended to burnish the edge past a certain point, which diminished cutting aggression. That's where the relatively fine grit of the alumina ceramic started having trouble shaping & thinning the harder vanadium carbides at the edge.
 
Diamond sharpening stones have high productivity and may be used for wide range of materials: carbide, cast iron, HSS, ceramics; not recommended for carbon steels.
Cubic boron nitride sharpening stones are designed for high quality processing of steels. Brand names of CBN are elbor, cubonite, borazon, etc.
 
abrasivetools said:
Diamond sharpening stones have high productivity and may be used for wide range of materials: carbide, cast iron, HSS, ceramics; not recommended for carbon steels.
Cubic boron nitride sharpening stones are designed for high quality processing of steels. Brand names of CBN are elbor, cubonite, borazon, etc.
Click to expand...
Why?
 
garry3 said:
Why?
Click to expand...
Not applicable to manual grinding. At high temperature, grinding with diamond in industrial settings can cause carbon to migrate from the diamonds into carbon steels and make them start performing wonky, which is why CBN is preferred for those applications. In hand sharpening it's not going to make any difference.
 
FortyTwoBlades said:
Not applicable to manual grinding. At high temperature, grinding with diamond in industrial settings can cause carbon to migrate from the diamonds into carbon steels and make them start performing wonky, which is why CBN is preferred for those applications. In hand sharpening it's not going to make any difference.
Click to expand...
We are talking about stones here.
 
garry3 said:
Why?
Click to expand...
The manufacturer's main recommendation to avoid complaints
The probability of the blade heating up to 700°C is very small, but who knows what the user can do

And the same applies when people discuss glass ceramics, rubber, and other exotic bonds derived from power tools.
You just can not feel advantages, which appears on 35 m/s
 
Last edited by a moderator:
garry3 said:
We are talking about stones here.
Click to expand...
Yeah to be clear I was pointing out why that "not recommended" statement didn't make practical sense for the context of the conversation. But if someone had, say, a bench grinder they wanted a superabrasive wheel on it'd be a reason to choose CBN over diamond. It just REALLY needs the qualifying information of "at high temperature" is the issue, NOT manual or low-speed/wet grinding.

iu
 
I do not have any magnacut steel knives, but I do have some tool steel, D2, S7, S30v and have always used diamond sharpeners of some sort. Never had a problem. The harder the steel, it would only make sense to use harder sharpeners. Otherwise you would prematurely wear out your sharpeners if you did a lot of sharpening of those super hard steels, right ?
 
Looking at edges ground with AO with supersteels under 1000 magnification will show the carbides standing tall. Only something harder will smooth them out.
It is shown in the "Knife Deburring" book. Vadim stated in his book that "carbide tearout" can occur, dulling the edge.

I can see the carbides with my microscope but couldn't say if they make the knife perform differently. I imagine some difference, not sure how to measure it though.
 
You must log in or register to reply here.
Back
Top