Basic Diamond Set for Edge Pro from Gritomatic

[ricklee4570]

Basic Diamond (3)Stone Set [6" x ¾"]

Basic Diamond Set is used for sharpening knives on Edge Pro compatible knife sharpeners. Diamonds offer excellent performance in sharpening knives of any steel including high carbon, vanadium, and chromium steels. Diamond-bearing plates are mounted on the high-quality aluminum blank with laser...

www.gritomatic.com

Anybody have any experience with these? Very inexpensive. Made in China.

Are they fairly decent? Durable?

Thanks for any info!

 

[sickpuppy1]

I prefer diamond stone to be in a substrate like an epoxy r3sin or such. Those usually have diamonds throughout the mix so as they wear or get cleaned it is renewing and shows fresh diamonds so to speak.
Those appear to be like a diamond paste glued to metal and so when it wears, its done. That being said if you use reasonable pressures they may very well last a long time. But never as well as as say the venev stone or my fav, the Matrix stones.
Yes the price reflects the quality.

 

[c7m2p3]

Interesting. I just put it on order to give them a try. I have a suspicion that 1. these are going to wear a lot faster than more expensive varieties from Edge Pro themselves, Venev, or other manufacturers given the process of electro plated coatings almost always wear out faster than other methods. That being said...you are getting three diamond grits for under 30$ so replacing them when they do wear out wont break the bank like Venev stones or others can.

2. being from china the thickness of the stones is probably not going to match up well with other edge pro stones so switching and swapping between these stones and those you may already have for your edge pro are probably not going to work all that well or maintain the same edge angle.

 

[Papilio]

I do not have experience with those stones. But when it comes to (diamond) stones, there are hugh differences in quality.
The description says they are monocrystalline, which is good. Monocrystalline diamonds are much better than polycrystalline because they last longer and keep - once broken in - their grit size.
But if those stones are a good deal, can't say.

 

[Spey]

2. being from china the thickness of the stones is probably not going to match up well with other edge pro stones so switching and swapping between these stones and those you may already have for your edge pro are probably not going to work all that well or maintain the same edge angle.

Drill Collar Stop addition, to EdgePro, effectively eliminates issues of multiple thickness stones during a sharpening progression. (Best 3-dollar mod I have made to date)

 

[Mr.Wizard]

Spey The compensation is not exact. Most of the time it doesn't matter but when using very hard fine stones it is good to be aware of.

 

[cudgee]

Edited.

 

[Spey]

Spey The compensation is not exact. Most of the time it doesn't matter but when using very hard fine stones it is good to be aware of.

So long as the user is intellegent enough to accurately set the collar stop relative to the area of stone used, procedure produces very accurate and consistent bevels when changing between stones of varied thickness. Like ANY tool, only as accurate as the user.

EDIT:
Mr.Wizard
What does "when using very hard fine stones it is good to be aware of." have to do with adjusting for varying thickness of different stones, strops, etc. during a sharpening progression?

 

[Mr.Wizard]

Spey Mathematically the adjustment for thickness at the pivot rod is only exact when the stone arm and pivot rod are perpendicular, but the error is smaller in magnitude than the inherent inaccuracy of the Edge Pro, e.g. slop in the pivot block. With a sufficiently stiff jig it would be demonstrable however.

Stones matter in angle compensation simply because if your angle is slightly off with a fast cutting stone it will quickly grind the bevel to the new angle, and with something muddy or conforming like leather it will still hit the entire bevel. However very hard, fine stones like Spyderco Fine ceramic rods are unforgiving.

 

[Spey]

Spey Mathematically the adjustment for thickness at the pivot rod is only exact when the stone arm and pivot rod are perpendicular, ...

When using the collar-stop method, the "compensation" (adjustment for stones of varying thickness during a sharpening progession) requires NO measuring or Math.

The angle of the stone (as it applies grind to bevel) is consistent both left & right of center, as it is at center (as I display in video below). Please take the time to read my notes section of video, as many have hard time comprehending what they are seeing.

Knife Sharpener Jig Debate - Left/Right Angle Change

 

[777 Edge]

Basic Diamond (3)Stone Set [6" x ¾"]

Basic Diamond Set is used for sharpening knives on Edge Pro compatible knife sharpeners. Diamonds offer excellent performance in sharpening knives of any steel including high carbon, vanadium, and chromium steels. Diamond-bearing plates are mounted on the high-quality aluminum blank with laser...

www.gritomatic.com

Anybody have any experience with these? Very inexpensive. Made in China.

Are they fairly decent? Durable?

Thanks for any info!

I've used them extensively and they are perfectly fine, good quality diamond electroplated stones.

Make sure to use some soapy water as a lubricant on the stones (a couple drops of dish liquid soap mixed with water in a dropper bottle works well).

When used dry, they will wear out faster - just like any other diamond electroplated stone does.

A lot of places state that these types of stones can be used dry - yes they work just fine when used dry, but they will wear out fast.

If lubricated, they last a heck of a long time.

 

[3D Anvil]

When using the collar-stop method, the "compensation" (adjustment for stones of varying thickness during a sharpening progession) requires NO measuring or Math.

The angle of the stone (as it applies grind to bevel) is consistent both left & right of center, as it is at center (as I display in video below). Please take the time to read my notes section of video, as many have hard time comprehending what they are seeing.

Knife Sharpener Jig Debate - Left/Right Angle Change

That is not correct. You are rotating the measuring device, which does not reflect the actual edge angle.

It's basic geometry. The edge angle is determined by the acute angle of the triangle formed by the sharpener's pivot, the intersection of the rod holding the pivot and the plane of the blade edge, and the contact point on the edge. When you move the stone holder off center, you are lengthening the triangle and thus the bevel angle MUST change because the length of the third side of the triangle remains constant.

The only time that would not be the case is if you had a curved blade exactly matching the arc of the pivot arm.

In practice it doesn't make that much difference, because as a rule the small change in angle due to the fixed angle system is minor relative to the variation in the blade grind thickness along the edge.

 

[777 Edge]

That is not correct. You are rotating the measuring device, which does not reflect the actual edge angle.

It's basic geometry. The edge angle is determined by the acute angle of the triangle formed by the sharpener's pivot, the intersection of the rod holding the pivot and the plane of the blade edge, and the contact point on the edge. When you move the stone holder off center, you are lengthening the triangle and thus the bevel angle MUST change because the length of the third side of the triangle remains constant.

The only time that would not be the case is if you had a curved blade exactly matching the arc of the pivot arm.

In practice it doesn't make that much difference, because as a rule the small change in angle due to the fixed angle system is minor relative to the variation in the blade grind thickness along the edge.

Actually, no this is not entirely correct 3D Anvil

The sharpening angle does not change. It's a widely misconceived idea with many users of fixed angle systems. Yes, you're right about basic triangle math but that's not the actual sharpening angle.

Remember, the further you go left or right of the pivot, the more the stone also slopes towards you while sharpening the edge.

Think of it like a pitched roof on a house. Now think of tying a piece of rope right in the top center of the roof and then pull out the rope straight down from the tie point (pivot) to the gutter. Then pull the rope to either side of the bottom of the roof, along the gutter. The roof pitch (angle) does not change, that's fixed. The angle of the rope from the pivot as observed does change and also gets longer but the roof pitch is constant.

The roof pitch above in my example equates to sharpening angle and the rope equates to the sharpening stone arm.

The only sharpening angle change that you'll have, is when the blade curves away from the parallel line drawn (imaginary) between the pivot point and the clamp point.

Now, there is actually a tiny sharpening angular change if the pivot rotation is not center on the pivot point (like with an Edge Pro as an example), but I'm not going to get into that for now.

 

[Mr.Wizard]

Spey Why are you conflating stone thickness compensation with angle tracking across the sweep of the arm? There are two separate issues.

If the stop collar has a face perpendicular to the axis of the pivot mast and the stone is placed flat against this face when adjusting for thickness the offset is only true when the mast and stone arm are perpendicular. When they are not the offset caused by the thickness of the stone against the edge of the knife is not in the same plane as that dialed in at the pivot. In practice the error is small but it does exist. Please consider the illustrations below. If it is still not clear I shall make another illustration.

To provide perfect compensation the pivot would need to be moved t/cos(a) where t is the thickness of the stone and a is the angle in radians between the stone arm and the normal of the back post (zero when the two are perpendicular). So when the stone arm and back post are close to perpendicular you can get away with a lot of thickness variation.

A quick illustration, not to scale. In the first figure moving the pivot up 6mm and the arm away from the table 6mm will keep it at the same angle. In the second the arm–post angle is 19° off perpendicular, so you would need to move the post up 6mm/cos(19°) ≈ 6.35mm to keep the same angle.

 

[3D Anvil]

Not quite, 777 Edge. The stone only pitches if the blade is curved -- like along the belly of a drop point blade. If you have a long, straight blade, the stone won't pitch and the angle will change geometrically. So yes, if you have a curved blade then the error is reduced, and in fact if the blade is curved enough, you can actually get a higher angle towards the tip than you have in the middle of the blade. As I said, the closer the curvature of the blade is to the arc of the pendulum, the less variation you get.

 

[777 Edge]

If you have a long, straight blade, the stone won't pitch and the angle will change geometrically.

No, not at all for the actual sharpening angle. Like I said it's a very common misunderstood theory. Have a look at this video below, it will help explain.

You are correct regarding a very curved blade, but not exactly for the reason you think. When it curves back from the perpendicular line of sharpening, then the sharpening angle does change.

What confuses guys even more, is the fact that you see an angle change on your digital angle cube if you move away from the center, and guys take this as more "proof" that the sharpening angle changes. It does not. If you want to measure the real sharpening angle, you should be rotating your angle cube to be perpendicular with the blade sharpening line. When you rotate your angle cube to get it perpendicular, immediately you'll see the angle change significantly on the screen and give you the correct sharpening angle.

 

[3D Anvil]

You know what?

You're right!

I guess the mistake I made was assuming the geometry was determined by a triangle, when in fact it's just a 2D plane that's involved. I just did a 3D simulation of sorts and there is no question that the bevel angle is unchanged, assuming a straight blade.

My apologies.

 

[3D Anvil]

Here are some screen shots, for what it's worth.

Here's the setup: the cross bar represents the blade edge. The two arms representing the legs of the "A" are the cutters. one was created dead center, and I copied it and rotated it on a 2D plane to reach the heel of the edge.



Then I used boolean operations to cut the cutters out of the blade:



And the definitive view is the one from the side, showing that the cut angle is identical in both cases:

 

[777 Edge]

You know what?

You're right!

I guess the mistake I made was assuming the geometry was determined by a triangle, when in fact it's just a 2D plane that's involved. I just did a 3D simulation of sorts and there is no question that the bevel angle is unchanged, assuming a straight blade.

My apologies.

No apologies necessary, it is a topic that comes up very regularly.

I'm glad you took the time to think about it and figure out what's really happening with the angles. Sadly, many guys don't take the time to put some though into it and just continue arguing an incorrect theory.

 

[Spey]

Mr.Wizard & 3D Anvil

It seems ..., we are more or less on same page at this point.

Curious if you have any remaining issues related to my comments on collar-stop use & accuracy, and/or left/right of table center as related to applied stone to blade bevel angles ?

My video from 4-5 years ago (Post #10 above) was a direct response to Simple Life original (and incorrect) video on the subject, and a few days later he posted that "I'm Sorry" was wrong correction video (Post #16 above by 777 Edge)

Regards,