DMT Aligner

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flphotog

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I ordered a DMT Aligner but after doing some additional research I'm having second thoughts. I found an instruction sheet and it appears that on a longer blade such as an 8 in Chefs knife it will not hold a consistent angle on the edge as the angle is dependent on the width of the blade. If this is the case the angle will vary as you move from the heel to the point.
Does anyone know if this is true or not?
 
Aligner works fine with 8 inch blades. On longer blades, sharpen closest to the handle first and then just slide it down the spine and continue sharpening.

Some people overthink this sharpening thing (self included :) )
 
If you read the thread angles-on-clamp-style-devices, it should answer your question... the same principle applies.

The short answer: You can set a blade so that you can get a consistent angle along the entire length, within the limits of the device itself (for example, how long the length of the guide rod is). You'll also need a way to check the angle, as the angle marks on the device typically work for only a particular set of conditions (for example, the blade extends ½" in front of the clamp).
 
Thanks, I've ordered it so I'll give it a try. Also have an angle cube coming so I can verify as I go.
 
Just set the clamp at the center of the blade, midway between the heel & tip; the Aligner will handle it easily enough. It's more important that the contact be flush and consistent for each given portion of the bevels, than it is for the angle to be exactly the same value from heel-to-tip; working from a single clamped position maintains that consistent contact throughout the sharpening process. Moving the clamp to different portions of the blade just introduces opportunity for the overlapping portions to be inconsistent, resulting in a less-than-flat bevels and possibly a less-than-crisp apex in those portions. A crisp apex at the intersection of perfectly flat bevels is worth much more than trying to keep an arbitrary angle value the same along the whole edge.


David
 
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Obsessed with Edges said:
Just set the clamp at the center of the blade, midway between the heel & tip; the Aligner will handle it easily enough. It's more important that the contact be flush and consistent for each given portion of the bevels, than it is for the angle to be exactly the same value from heel-to-tip; working from a single clamped position maintains that consistent contact throughout the sharpening process. Moving the clamp to different portions of the blade just introduces opportunity for the overlapping portions to be inconsistent, resulting in a less-than-flat bevels and possibly a less-than-crisp apex in those portions. A crisp apex at the intersection of perfectly flat bevels is worth much more than trying to keep an arbitrary angle value the same along the whole edge.
David
Click to expand...

While I'd agree that "moving the clamp to different portions of the blade" should be avoided (although this wasn't brought up to begin with), the advice to "just clamp at the center of the blade" is in general, not a good idea. It will usually lead (depending on the blade of course) to a wide area near the tip, or a tip that the user complains won't get sharp.

Far better to get an understanding of how the angle changes in a clamped device. It would actually be better in most cases to clamp closer to the tip area, and not the center, even if the goal is to cover the entire length of a longer blade.
 
cbwx34 said:
While I'd agree that "moving the clamp to different portions of the blade" should be avoided (although this wasn't brought up to begin with), the advice to "just clamp at the center of the blade" is in general, not a good idea. It will usually lead (depending on the blade of course) to a wide area near the tip, or a tip that the user complains won't get sharp.

Far better to get an understanding of how the angle changes in a clamped device. It would actually be better in most cases to clamp closer to the tip area, and not the center, even if the goal is to cover the entire length of a longer blade.
Click to expand...

This morning I was reprofiling a buck 112 with my dmt magna guide. One thing I noticed while setting the clamp position was that the very high upsweep in the clip point was causing a very low angle at the tip and would have caused a really wide bevel. I repositioned the clamp so that if you drew a strait line from the center of the upsweep on the clip point to the ricasso, this line would be perpendicular to the clamp. This made the bevel width more uniform than it would have been had I positioned the clamp 90° to the spine.

The next thing I noticed was that the staggered position of the guide rods was causing a wider bevel at the tip than the other. I remedied this by only using one guide rod and flipping it over each time I flipped the knife.
 
Moving the clamp was brought up in another post in the thread, which is why I mentioned that.

I'll stick with my recommendation; I've used the Aligner (and Lansky, and Gatco) with knives such as mentioned, and it'll easily reach to either end of an 8" chef's knife with minimal issues. Consistency of the angle itself is basically a moot point, as it never happens in reality anyway. Even good factory edges are unlikely to maintain exactly the same angle from heel to tip; this is evidenced in factory bevels that remain evenly wide (for appearance's sake, and little else), despite the blade thickness varying (tapering) as one approaches the tip, on most knives. Varying the angle is the only way to keep those factory bevels at an even width. The variation in thickness of steel behind the edge will have the bigger impact on the appearance (width) of the bevels, more so than the set distance from clamp to edge.

Working from a single fixed position on the blade eliminates new potential for inconsistency in bevel flatness and therefore edge crispness. That'll contribute to the end goal of 'sharp' more than anything else. And moving the clamp to a couple/three different positions still won't even guarantee a consistent angle. Every millimeter of the edge's length would have to remain exactly the same distance from the clamp at all times to guarantee an unvarying angle; and that'll never happen anyway, unless the knife's edge itself sweeps in a perfectly circular arc around the clamp (if you're sharpening an ulu, it might come close).


David
 
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sc00ts... Yes, glad you brought this up... you can also angle the blade to achieve the desired result.


Obsessed with Edges said:
Moving the clamp was brought up in another post in the thread, which is why I mentioned that.

I'll stick with my recommendation; I've used the Aligner (and Lansky, and Gatco) with knives such as mentioned, and it'll easily reach to either end of an 8" chef's knife with little issues. Consistency of the angle itself is basically a moot point, as it never happens in reality anyway. Even good factory edges are unlikely to maintain exactly the same angle from heel to tip; this is evidenced in factory bevels that remain evenly wide (for appearance's sake, and little else), despite the blade thickness varying (tapering) as one approaches the tip, on most knives. The variation in thickness of steel behind the edge will have the bigger impact on the appearance (width) of the bevels, more so than the set distance from clamp to edge.

Working from a single fixed position on the blade eliminates new potential for inconsistency in bevel flatness and therefore edge crispness. That'll contribute to the end goal of 'sharp' more than anything else. And moving the clamp to a couple/three different positions still won't even guarantee a consistent angle. Every millimeter of the edge's length would have to remain exactly the same distance from the clamp at all times to guarantee an unvarying angle; and that'll never happen anyway, unless the knife's edge itself sweeps in a perfectly circular arc around the clamp (if you're sharpening an ulu, it might come close).
David
Click to expand...

Let's eliminate reclamping the blade from the conversation, I think we both agree this should be avoided if possible.

Maybe just some clarification is needed. If your advice to clamp in the center was specifically related to the Chef's knife, then yes that would probably be ok. There's usually little belly or curve toward the tip, so there won't be a lot of angle change. As sc00ts said, you could also angle the blade a bit and compensate.

But if you put in, for example, a 6" hunting knife, and just clamped it in the middle, when you moved around the belly toward the tip (which is more pronounced than a chef's knife), not only are you now sharpening into thicker metal like you said, but you're also sharpening at what is probably a lower angle than the rest of the knife. You're right, just keeping the same angle will make it a bit wider, and I'm not suggesting sharpening for "looks", but at the same time, unless you have a specific reason, you don't want to end up sharpening even lower at the tip, which is what would happen if you used the center to clamp.
 
Since the OP was specifically concerned about the chef's knife, that's what I was addressing. Chef's knives are easy, maybe the easiest, with setups like this, and eliminating additional complications, like moving the clamp will go further toward getting the job done with good results. Smaller & narrower blades, including many hunting knives, I think are actually more tricky, because the differences in clamp-to-edge distances are usually proportionally more extreme, with the edge being VERY close to the clamp in some positions (edge and clamp near mid-blade, for example), and much further away at other times, such as with clamp at mid-blade while sharpening the tip. Not to mention, it's often difficult or tricky to get enough 'real estate' to clamp to on smaller/narrower blades; more so if they're hollow/sabre-grind. On smaller blades like that (usually 4"-5" blades or less), I've often clamped to the ricasso/tang, just to give it a steadier base from which to hold. But I almost never move the clamp unless the hone can't physically reach all portions of a very large blade. And even then, the DMT Aligner clamp can be used with a large bench stone (the DMT clamp is at it's best, used as such), which essentially renders the problem moot. For a chef's knife in particular, that's likely the best approach anyway; DMT actually demo's the Aligner clamp used with a bench stone to sharpen a chef's knife, in one of their own videos.


David
 
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I agree with David. When I get tired of sharpening my employees kitchen knives I usually buy them an aligner. A good central blade location produces good, workable results. Russ
 
Received the Aligner a couple of days ago and so far mostly happy with it. I did also get an Angle Cube to verify the angles as I didn't fully trust it. They appear to be pretty close to spec for the most part at least. I would be happier if there was a way to manually adjust the angle instead of just using the presets but I knew that wasn't the case up front so I can't bitch to much.
I am disappointed that my Becker/Kbar BK2 does not fit the clamp but not a really major problem as I have other ways to sharpen it.
All in all I'm happy with it, for the price it's very good. I will be keeping my sharpmaker as for a lot of things it's still the best.
 
The way I see it, you want to have the same length between the point where the aligner clamp "leg" touches the surface and the straight portion of the blade as well as the tip. Then you have the same angle all along the blade. It gets a bit trickier as soon as the blade gets too short.
 
awestib said:
The way I see it, you want to have the same length between the point where the aligner clamp "leg" touches the surface and the straight portion of the blade as well as the tip. Then you have the same angle all along the blade. It gets a bit trickier as soon as the blade gets too short.
Click to expand...

Yup (but also on a long blade it can be hard to setup that way)
 
I wonder if additional angles could be cut into the Aligner clamp stem? Has anybody tried it?
 
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