DMT Magna-guide questions

A

antikythera

Joined
Feb 13, 2009
Messages
74
Hello, all. I recently purchased a set of diafolds (C-EEF) and a magna-guide, and can get my knives to a relatively polished edge and sharp enough to sail through copy paper with no effort.

However, I was wondering about where edge angles came into play. I find that if I try to make a shallow angle with the aligner, the thumbwheel gets in the way, and I am forced to use a thicker edge bevel. How would I go about thinning out an edge in the first place?

My Delica 4 came with (as I found out recently) horribly asymmetric bevels, but I managed to even them out with some time and effort. It is extremely sharp, but I can't help but wonder if by thinning out the edge, I could get it even sharper (in terms of use, not necessarily edge smoothness on a micro-level, as I mostly cut fibrous material and LDPE type plastic with it).

And this problem (if it even is one) is compounded with my Kershaw OD-2 that has a really small blade width (~.5"), but the same thickness as the Delica.

Again, they both are sharp as it is (by my standards, anyway), but how would I go about thinning out the edge?

Thanks in advance!


EDIT: Oh by the way, I just matched the stock bevels (for the Delica, the shallower of the two bevels).
 
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With the aligner the thumbwheel does get in the way. I use the side opposite the wheel, and then flip the blade and re-clamp. I only use the shallowest angle, which seems to be just under 30 degrees inclusive. Keep in mind that the taller the blade from edge to spine, the shallower the angle will be. I only use the aligner for re-profiling a blade. After getting to the green diamond, a strop with compound works well, or even a sharpmaker with white rods and light pressure to maintain the edge, it only takes a second if you don't let it get too dull.
 
Okay, I'll try that.

Anything special I have to do to thin out the edge geometry? It seems that the contact point between the sharpener and the knife is pretty far away from the edge. I wouldn't want to have to take off too much steel...
 
Is there a risk of the plastic threads stripping? That seems like a lot of strain to put on threads that are:
a) plastic
and
b) not square (IIRC)

What is absorbing the force exerted by torquing the screw down? Obviously not the knife, as it's a piece of steel...
 
antikythera said:
Is there a risk of the plastic threads stripping? That seems like a lot of strain to put on threads that are:
a) plastic
and
b) not square (IIRC)

What is absorbing the force exerted by torquing the screw down? Obviously not the knife, as it's a piece of steel...
Click to expand...

You don't really need to have the thumbwheel really tight. It's plastic so it might not last too long if your really crank it up. Just enough tension so that the blade doesn't move around. I found out from some guys here that putting masking tape or painter's tape on the spot the clamp holds works quite well.
 
singularity35 said:
You don't really need to have the thumbwheel really tight. It's plastic so it might not last too long if your really crank it up. Just enough tension so that the blade doesn't move around. I found out from some guys here that putting masking tape or painter's tape on the spot the clamp holds works quite well.
Click to expand...

That's what I've been doing so far (not with tape), and I'm having a really hard time getting a shallow angle with the stones. I guess I'll just flip the blade every so often...


But again, how do I thin out an edge to begin with? I've done the sharpie trick, and the abraded section is far above the edge, actually before the primary grind.
 
You just answered your own question ;)

Using your coarsest stone simply grind at a lower setting, if the grind marks are at the top of the bevel then you know your at a lower angle. Grind until those marks reach the edge and you have just reprofiled your edge.

It may be plastic but your not going to break it, always make sure the plastic screw is as tight as possible.
 
knifenut1013 said:
You just answered your own question ;)

Using your coarsest stone simply grind at a lower setting, if the grind marks are at the top of the bevel then you know your at a lower angle. Grind until those marks reach the edge and you have just reprofiled your edge.

It may be plastic but your not going to break it, always make sure the plastic screw is as tight as possible.
Click to expand...

Oh, that's nice! :D

Should I be worried about removing too much metal? I wouldn't want the edge to start receding a whole lot...
 
Your bevel will get wider but its not going to take off any length/width
 
I used the Magna Guide for awhile then "chucked it" and went freehand with the dia-folds. That way I can put whatever bevel feels right to me. It just takes a little more concentration and I get much sharper edges.

The more you freehand the easier it gets. The key for me was learning to freeze my knife, hand, arm, etc. and just use very slight turns of the waist. An inch or so of turning at the trunk is multiplied several times, by the time it reaches your blade & stone. That keeps the edge on track - for me anyway. :D

BTW, I'd get the x-coarse for reprofiling. Using kinda light pressure, that sucker cuts fast!
 
cziv said:
I used the Magna Guide for awhile then "chucked it" and went freehand with the dia-folds. That way I can put whatever bevel feels right to me. It just takes a little more concentration and I get much sharper edges.

The more you freehand the easier it gets. The key for me was learning to freeze my knife, hand, arm, etc. and just use very slight turns of the waist. An inch or so of turning at the trunk is multiplied several times, by the time it reaches your blade & stone. That keeps the edge on track - for me anyway. :D

BTW, I'd get the x-coarse for reprofiling. Using kinda light pressure, that sucker cuts fast!
Click to expand...

I got tired of maneuvering around the Magna-guide with my OD-2, so I just started freehanding it. It works amazingly well for larger kitchen knives, though.

Back to the OD-2, (perhaps this is because of the "lesser" steel) it actually looks quite polished compared to Magna-guide usage after a couple of swipes on coarse, surprisingly enough. I wonder how it will turn out after a run through the other grits... :D

I hope the guide wasn't a waste of $20...
 
antikythera said:
I got tired of maneuvering around the Magna-guide with my OD-2, so I just started freehanding it. It works amazingly well for larger kitchen knives, though.

I hope the guide wasn't a waste of $20...
Click to expand...

When I got my guide I complained about the same things as above. I found out I wasn't hitting anything (by looking sideways at my strokes) even though it felt like it. Also, clamp those little blades way at the back of the spine and don't be afraid of raising the guide a notch if thats what it takes. Mine works great, it's just easier without it. :)
 
The MG worked quite well on my Delica, but not on the OD-2. I guess it's probably a size thing, as the MG sharpened my kitchen knives very easily.

I got an edge on my OD-2 freehand that can push-cut newspaper, but it almost looks convex, just by letting the light play over the edge. Could rolling my wrist while sharpening have caused that?
 
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