Homemade Sharpening Guide - Thoughts?

[tobiusnc]

I just bought a DMT magna-4 set and while waiting for it to arrive, I started looking at the more expensive systems like the EdgePro. I also found this one from New Zealand that I thought was interesting.
http://www.scarysharp.co.nz/specs.php

I'm contemplating building one that's kind of a hybrid of the two. Use the blade holding system similar to the EdgePro (with a few enhancements) but an adjustable guide rail instead of a pivot, similar to the ScarySharp. I like the guide rail because it allows a longer knife to be sharpened without being moved. I'm trying to determine if a pivot for the stone holder has benefits to holding the angle better than a guide rail. It seems like the guide rail would be as good or better, but I'd like to lean on the collective wisdom of the group.

One thing that I'd like my design to be able to do is also sharpen long pieces, such as hand plane blades or chisels, which none of the popular ones are able to do. I think I'm close to having a design that works, but I'm not quite ready to share.

Thanks!

 

[cbwx34]

I just bought a DMT magna-4 set and while waiting for it to arrive, I started looking at the more expensive systems like the EdgePro. I also found this one from New Zealand that I thought was interesting.
http://www.scarysharp.co.nz/specs.php

I'm contemplating building one that's kind of a hybrid of the two. Use the blade holding system similar to the EdgePro (with a few enhancements) but an adjustable guide rail instead of a pivot, similar to the ScarySharp. I like the guide rail because it allows a longer knife to be sharpened without being moved. I'm trying to determine if a pivot for the stone holder has benefits to holding the angle better than a guide rail. It seems like the guide rail would be as good or better, but I'd like to lean on the collective wisdom of the group.

One thing that I'd like my design to be able to do is also sharpen long pieces, such as hand plane blades or chisels, which none of the popular ones are able to do. I think I'm close to having a design that works, but I'm not quite ready to share.

Thanks!

You mean something like this?

I used one...(do a search for ezesharp).

I'll make a few comments to start the conversation. One, using a full size stone in this manner, I found not to be the best way to sharpen... especially if trying to do detail work. Seems more suited for a kitchen or industrial setting, where you just want a decent edge on a knife and get back to work. (Actually worked better with an EdgePro stone holder).

Second is the pivot on the ezesharp was a bit inaccurate... it would change during sharpening. Finally the stone holder was a bit 'fussy'... hard to duplicate. I ended up making a jig to simplify it.

Gotta say, not really impressed with the design of the one in your link... seems lacking.

Anyway, there's a gazillion EdgePro knockoffs and imitations now... lots of ideas to choose from! Just thought I'd give a few ideas of maybe where to concentrate your efforts.

 

[tobiusnc]

That's very close to what I have in mind. Here's a picture from Sketchup. This show using the DMT diafold and magnetic holder from the Magna kit. (The scale of the knife is off a bit, the horizontal guide rod is roughly 10" long.) Notice the open back will allow longer items to be sharpened, and the t slots allow use of several different clamps/holders depending on the item being sharpened.

I don't understand what you mean about the pivot on the ezsharp changing during sharpening? Do you know what was causing it to change?

 

[cbwx34]

That's very close to what I have in mind. Here's a picture from Sketchup. This show using the DMT diafold and magnetic holder from the Magna kit. (The scale of the knife is off a bit, the guide rod is roughly 10" long.) Notice the open back will allow longer items to be sharpened, and the t slots allow use of several different clamps/holders depending on the item being sharpened.

I don't understand what you mean about the pivot on the ezsharp changing during sharpening? Do you know what was causing it to change?

I should have said blade angle, not the pivot. It's been a while, but the Ezesharp clamped the blade, you could then rotate the clamp 180 deg. to work each side (it was spring loaded if I remember right). Anyway, when rotating the knife something would change causing the angle to change... not much, but enough so that the angle no longer matched. You could reset for the new angle, then a couple of rotations it would be off again. Never figured out why. Kinda why I thought it was more of an industrial sharpener.

You're design's lookin good... keep us posted. The only thing I would wonder about is angle change as you sharpen the belly and towards the tip... you'll probably need to experiment a bit and see how it does.

 

[tobiusnc]

I should have said blade angle, not the pivot. It's been a while, but the Ezesharp clamped the blade, you could then rotate the clamp 180 deg. to work each side (it was spring loaded if I remember right). Anyway, when rotating the knife something would change causing the angle to change... not much, but enough so that the angle no longer matched. You could reset for the new angle, then a couple of rotations it would be off again. Never figured out why. Kinda why I thought it was more of an industrial sharpener.

You're design's lookin good... keep us posted. The only thing I would wonder about is angle change as you sharpen the belly and towards the tip... you'll probably need to experiment a bit and see how it does.

My goal with this is to have something that works similar to the EdgePro, but has more flexibility. Allowing it to be used without clamps like the EdgePro to make a few passes to touch up a blade in good shape, or the blade could be clamped down for long term work like changing profile. Rigidity and consistency are my primary goals. For myself, I don't see me changing the angle very often, so I want something that I can get a repeatable angle for quick touch-ups.

As for the angle change as it gets to the tip, don't all the systems (EdgePro, Wicked Edge, etc.) have the same problem? Do you see anything in my design that makes it worse?

 

[cbwx34]

As for the angle change as it gets to the tip, don't all the systems (EdgePro, Wicked Edge, etc.) have the same problem? Do you see anything in my design that makes it worse?

As you've already figured out, the distance from the pivot changes the angle, so in your design, as you move toward the tip, the angle will increase. In the case of the EdgePro, WE, etc. since the pivot is in one place, you can compensate by locating the belly/tip a different distance to compensate. Here's an example from the WE...

Your design isn't 'worse', you'll just need a way to compensate. If you moved the rod directly in front of the belly/tip, my theory is the angle will increase. Not a bad thing, just something to consider.

 

[Vinifera]

This issue seems to come up quite often. I don't have the answer but some disagree with the angle change unless the blade is curved. http://www.bladeforums.com/forums/showthread.php/1392923-Does-the-Wicked-Edge-system-really-keep-a-constant-angle?p=16054484#post16054484 which was taken from another thread related to the same thing.

 

[fvdk]

This issue seems to come up quite often. I don't have the answer but some disagree with the angle change unless the blade is curved. http://www.bladeforums.com/forums/showthread.php/1392923-Does-the-Wicked-Edge-system-really-keep-a-constant-angle?p=16054484#post16054484 which was taken from another thread related to the same thing.

I think you're misreading cbwx34's post/sketch. It is not about angle changes in the straight portion of the knife but about about the tip. It illustrates that the angle changes on the curved portion of the blade but how much, depends on the placement in the clamp.

In the illustration it shows that the angle stays nearly the same (26.3 degrees) if placed at the same distance from the pivot point as the edge of the knife while it changes a lot (17.5 degrees) if placed further away.

And yes, this only applies to the curved part of the knife. The angle does not change on the straight portion of the knife.

 

[cbwx34]

I think you're misreading cbwx34's post/sketch. It is not about angle changes in the straight portion of the knife but about about the tip. It illustrates that the angle changes on the curved portion of the blade but how much, depends on the placement in the clamp.

In the illustration it shows that the angle stays nearly the same (26.3 degrees) if placed at the same distance from the pivot point as the edge of the knife while it changes a lot (17.5 degrees) if placed further away.

And yes, this only applies to the curved part of the knife. The angle does not change on the straight portion of the knife.

Yup :thumbup:

 

[Jason B.]

I think the DMT aligner clamp should be the focus.

When used freely with benchstones the issues of pivot point and tip angle go away because the post determining angle is riding freely in any direction. It also allows free movement of the handle to easily flow through even the deepest bellied knives without widening the tip.

The only issue is it cheap and could be made so much better. All aluminum with hard delrin tips so it slides smoothly on surfaces and some rubber pads in the clamp to allow for a better hold on the blade. As-is you need to put a little painter tape under the clamp jaws and be careful of how much sharpening pressure you use because the clamp will flex. The flexing then causes small angle variation between stones making multi stone progressions very difficult.

 

[cbwx34]

I think the DMT aligner clamp should be the focus.

When used freely with benchstones the issues of pivot point and tip angle go away because the post determining angle is riding freely in any direction. It also allows free movement of the handle to easily flow through even the deepest bellied knives without widening the tip.

I don't think that's correct... the position of the clamp would still alter the angle as you approach the tip, if you used the clamp as the guide. You're right that it allows more freedom of the handle... in that you could forego the use of the guide as you approached the tip... essentially freehanding that area. But if you want to use the Aligner clamp as a guide for the belly/tip area... the same rules apply.

 

[eKretz]

For the device depicted in post #3, put a stop block on the rod that is parallel to the straight portion of the edge. Place it so that it is near the beginning of the curved portion of the edge but slightly before, and it will at least reduce the angle change. Still won't be perfect, but good enough for government work.

I made a similar setup many years ago before I started sharpening freehand.

 

[Jason B.]

I don't think that's correct... the position of the clamp would still alter the angle as you approach the tip, if you used the clamp as the guide. You're right that it allows more freedom of the handle... in that you could forego the use of the guide as you approached the tip... essentially freehanding that area. But if you want to use the Aligner clamp as a guide for the belly/tip area... the same rules apply.

In my experience with the aligner tool and benchstones that is not the case.

 

[cbwx34]

For the device depicted in post #3, put a stop block on the rod that is parallel to the straight portion of the edge. Place it so that it is near the beginning of the curved portion of the edge but slightly before, and it will at least reduce the angle change. Still won't be perfect, but good enough for government work.

Good idea.

In my experience with the aligner tool and benchstones that is not the case.

Sure it will. I even checked to be sure. Easiest way to see it is to clamp a blade near the heel (loose enough you can slide it). Then set the tip on the stone using the clamp as a guide. Now slide the clamp toward the tip... you can see it changing the angle at the tip if you continue using the clamp as a guide (makes the angle greater).

Based on your freehand edges, I don't think you've ever used a clamp. ('cause his freehand edges are great for those who might think I'm insulting him).