Hapstone R8 question

Leo Greer

Leo Greer

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Dec 30, 2021
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Hey guys! At this point it was well past time, my Work Sharp fixed angle just isn’t cutting it. It’s wobbly, hard to use, and the stones it came with (even with the advanced set), were getting worn out. I couldn’t put any kind of flat bevel on anything—everything ended up convex because of the wobbly clamp.

So I bought a Hapstone R8 from Gritomatic, and I noticed they had diamond stone bundles on the same page. I check the compatibility listing. Says they’re for Hapstone and Tsprof.

No, the stones are not. The Hapstone needs Edge Pro stones despite what the gritomatic website claimed.

So here’s my question.

Are there alternate stone clamps I need to buy to make these Venev Ursa stones work, or should I be trying to get Gritomatic to switch out the stone set for listing the compatibility wrong?

I’m leaning towards the second option, as it really seems to be kinda scummy to offer bundles of stones listed as compatible, on the product page, as an add on… and have them be incompatible.

Here’s a photo of how the stones fit. Am I missing something?

To me it looks like these clamps are only designed for Edge Pro style stones and Gritomatic just mislabeled the compatibility.


IMG_3037.jpeg
 
Leo Greer said:
To me it looks like these clamps are only designed for Edge Pro style stones and Gritomatic just mislabeled the compatibility.
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No, they work fine. I use Ursa stones on my Hapstone systems all the time. Yes, they won't be as secure as a dovetail plate backed stone but they do work just fine.

Shorten the distance between your clamps so the spring is almost completely tightened up when the stone is clamped. If you still don't like the clamping, then stick a strip of rubberized tape on the ends of the stones.
 
777 Edge said:
No, they work fine. I use Ursa stones on my Hapstone systems all the time. Yes, they won't be as secure as a dovetail plate backed stone but they do work just fine.

Shorten the distance between your clamps so the spring is almost completely tightened up when the stone is clamped. If you still don't like the clamping, then stick a strip of rubberized tape on the ends of the stones.
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Does this look correct? I genuinely want this to work, but I also have expensive knives and marring a blade would be unfortunate.

I’m trying things out on a beater bushcraft knife.

image.jpg
 
Leo Greer said:
Does this look correct?
Click to expand...

The stone clamping looks good to me.

While sharpening, the stone will seat and shouldn't move out of the clamp... unless you slip and bang the edge of the stone against the knife.

When you lift the stone up and away from the blade and you're concerned it may slip out, simply pinch it with your thumb and index finger when you lift it up.
 
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Leo Greer said:
and marring a blade would be unfortunate.
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You're most likely to marr the blade if your stroke is too long and you slip up and over the edge while sharpening. Use a spring stopper if you're concerned you might stroke up and over the edge.
 
IMG_3040.jpeg

IMG_3039.jpeg

I’ll call the first sharpening a success! Not only is the stability of this system Infinitely better than my Work Sharp, but the Venev stones cut the steel on my test knife (MagnaCut at 63) effortlessly, producing a nice toothy edge that’s sharp enough to slice an errant pass from a finger.

Obviously MagnaCut is relatively easy to sharpen compared to steels like M390 or S90V, but I feel quite confident the stones will hold up.
 
Leo Greer said:
Does this look correct? I genuinely want this to work, but I also have expensive knives and marring a blade would be unfortunate.

I’m trying things out on a beater bushcraft knife.

View attachment 3191060
Click to expand...

Your angle cube is not correct, you will want to zero the cube on the back of the magnetic table, not the base of the sharpener. It can be a bit finicky as there isn't a specific spot for the cube so just hold it in place and make sure it is in line with the sharpening arm and not twisted to the side and the angles will be close enough.

If you really want to get deep into the weeds, you would zero the cube on the table, then measure the angle on your knife blade, divide it into 2, then add that to your desired angle to get the "true" angle you should set the sharpener at. This is because with a "FFG" style knife on the table you are not measuring from the middle of the spine to the edge like it would be in a clamp. So for instance if you measured the angle of the knife at 4° and you wanted a 20° edge, you would measure on the arm to 22° total to account for the knife not being "flat". It isn't really a big deal for most knives and not at all for ones where the main flats are square with the spine.

If you want more grip on the Venev stones you can use a triangular file to cut notches into the ends to match the dovetail a bit, but it is not really needed.
 
Bdtry said:
Your angle cube is not correct, you will want to zero the cube on the back of the magnetic table, not the base of the sharpener. It can be a bit finicky as there isn't a specific spot for the cube so just hold it in place and make sure it is in line with the sharpening arm and not twisted to the side and the angles will be close enough.

If you really want to get deep into the weeds, you would zero the cube on the table, then measure the angle on your knife blade, divide it into 2, then add that to your desired angle to get the "true" angle you should set the sharpener at. This is because with a "FFG" style knife on the table you are not measuring from the middle of the spine to the edge like it would be in a clamp. So for instance if you measured the angle of the knife at 4° and you wanted a 20° edge, you would measure on the arm to 22° total to account for the knife not being "flat". It isn't really a big deal for most knives and not at all for ones where the main flats are square with the spine.

If you want more grip on the Venev stones you can use a triangular file to cut notches into the ends to match the dovetail a bit, but it is not really needed.
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I actually zeroed my cube on the blade itself. Obviously that’s not exact, as you stated, but I’m not a professional and I don’t need that last degree or two of accuracy. This knife is also a tall FFG ground quite thin, so it matters even less.

I set the edge angle to 14 per side, which by my roughest of estimates translates to 16 in practice.
 
Diemaker said:
Maybe it's just the photo but it looks far steeper than 10 degrees.

PS, love the Delicatus granite.
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I reset the cube after this photo but was too lazy to take another photo! The angle is this photo is more like 30 degrees
 
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