Sharpmaker angles may be off

[Jason Paul]

Hi All,

Yesterday I used a marker on the edge of my Manix 2 LW, and started on the Sharpmaker in the 30-degree slots. After a handful of swipes I noticed the marker was being ground away on one side, but not the other.

Using a clinometer app on my phone, I found the angles were off on both sets of slots. What I'm getting is:

30-degree slots:
L - 14.1
R - 16.5

40-degree slots:
L - 19.4
R - 21.5

I'll admit I tend to be a bit OCD with this sort of thing - so I figured I'd ask here. Is this enough of a difference to be concerned about? Would this bother you at all?

Part of me says it's probably no big deal, and it's probably still as close to 15 and 20 degrees as freehand sharpening, so don't worry about it.

But another part of me wonders what consistently using angles that are slightly off might do over time.

To compensate I could reverse the Sharpmaker every sharpening or something, but that might be hard to keep track of. I thought of maybe trying to put something in the slots to bring the too-obtuse sides up to where they should be.

I don't know - any thoughts on this?

Thanks,
Jason

[bearfacedkiller]

Is your table or counter flat? Not that I want to direct your OCD towards how level your surfaces around your home are.

You can always place something under the base to make the angles equal either way.

In the end I think it will have very little to do with your finished product. We are talking about a very small difference here. Those of us that freehand probably have that much difference. Unless you are a robot there is likely more variation in the angle at which you are holding the knife. Just sharpen away my friend.

[JRinFL]

What Darby said ^

Otherwise you will need to spend a lot of money to get a system that produces near perfect angles, like a Wicked Edge or similar sharpening system.

[TenGrainBread]

I wouldn't be surprised if the slop engineered into the Sharpmaker holes led to a +/- 2 deg tolerance. The rods need to be inserted by a human hand, so making them press fit with extremely tight tolerances is going to violate that design requirement, in addition to causing wear to the plastic (if you are pressing an extremely hard ceramic rod into a plastic hole, the friction will cause the rod to wear away at the bore of the plastic hole). A more forgiving slip fit is necessary. This is conjecture, but seeing how much a rod can move within the hole, 2 degrees is a reasonable guess.

Second of all, I'd doubt the accuracy of a phone app clinometer. It probably uses the accelerometer in your phone, which is not a component that is designed for accurate angle measurements with a resolution of less than a degree. The other complicating factors is how you positioned your phone to take the measurements, how you zeroed the clinometer, etc...

[TkoK83Spy]

My left rod slot of my 40 deg setting is definitely waaaaaaaaay off compared to the right. The mold isn't "broken" but the rod flops around quite a bit. This pretty much forced me to learn to free hand on the Sharpmaker rods and find the correct angle myself, unless the 30 deg setting works for a particular knife, as those settings are an equal/snug fit. Kind of a waste of money, but at the same time I've learned a lot more this way. I am now acquiring more benchstones to make the job easier for something more than a quick touch up.

[Pokey]

Jason,

Good job of measuring the Tri-Angle rods, I never would have thought to do that. That's good info to keep in mind when you use your Sharpmaker. Probably not down to a tenth of a degree, but by just knowing one side is more obtuse than the other.

I'm not surprised that there are differences in those angles. I can think of a few reasons why there is a difference in the two sides. One would be the manufacturing tolerances of the plastic base of the Sharpmaker. I know on my Sharpmaker the holes in the base are a sloppy fit for the Tri-Angle rods to start with; mine wobble quite a bit when I put them in the base. If they were super tight you wouldn't be able to fit the Tri-Angles into the base.

Another thing is, I'll bet the angle of the Tri-Angles will change with time. Just as the Tri-Angles will grind away at the steel on your blade, they're grinding away at the holes in the Sharpmaker base and changing the angle of the rod. (I can see residual black stuff on the ends of my brown Tri-Angle rods coming from the base.) I'm on probably my second set of both white and brown rods. Are the dimensions of all the rods the same? That could change the angle from rod to rod. There's probably small manufacturing tolerances that happen on the Tri-Angle rods themselves. (Are all three sides perfectly flat?) I know Sal, some guy who works over at Spyderco, :D has posted that the white, fine, Tri-Angle rods are lapped to achieve a certain fineness to the grit on them. (one more tolerance thrown into the mix)

When you used a marker on the edge grind of your blade, then dragged it across the Tri-Angles not only were you seeing a difference in the Tri-Angles, you're seeing a difference in the grind angle on the two sides of the blade. (Not to mention the changes of the angle on each side of the blade.)

Using a marker on the grind angle and rolling the blade to match that angle on the Tri-Angle is really the only solution to smooth out the surface of the grind. We humans have the brains, eyes, dexterity, and markers to do that. Think of it this way, all the angles we've talked about are pretty much set digitally, we humans are the analog part that makes it work.

I cheat and use a Sharpie and body English on my knives, too.

[Pokey]

Is your table or counter flat? Not that I want to direct your OCD towards how level your surfaces around your home are.

You can always place something under the base to make the angles equal either way.

In the end I think it will have very little to do with your finished product. We are talking about a very small difference here. Those of us that freehand probably have that much difference. Unless you are a robot there is likely more variation in the angle at which you are holding the knife. Just sharpen away my friend.

Just for grins and giggles, turn the base 180° and measure those angle again. I'll bet they change, too.

[Sharp Guy]

What I found when I was making my SM style bases (with angles other than 30°& 40°) is that the dimensions of the stones vary a little. So they sit in the slots a little differently and therefore the angles vary a little. I have several sets of SM rods and I've measured each one. They're all a little different. Tightening up the slots seemed to help a little but they still varied a little. I know my CAD model is correct and my 3D printer is reasonably accurate. The varying angles is one of the reasons I only use my SM to add and touch up micro-bevels. I do the reprofiling on a fixed-angle system

[Abyss_Fish]

As long as your right handed this offset may actually be a benefit.

[Wartstein]

My left rod slot of my 40 deg setting is definitely waaaaaaaaay off compared to the right. The mold isn't "broken" but the rod flops around quite a bit. This pretty much forced me to learn to free hand on the Sharpmaker rods and find the correct angle myself, unless the 30 deg setting works for a particular knife, as those settings are an equal/snug fit. Kind of a waste of money, but at the same time I've learned a lot more this way. I am now acquiring more benchstones to make the job easier for something more than a quick touch up.

Funnny - that is exactly the same on my sharpmaker: 30 degree slots both hold rods very snug, but the left rod of the 40 setting sits loose and moves around a a lot.
Still I am really happy with my results, but I have to admit: I am definitely NOT "ocd", and don´t have too high expectations concerning the exactness of the angles. But if I´d want more accuracy (or will want some day) it could be an issue.
Furtermore, I use the 30 degree setting more than the 40 anyway.

[blues]

I checked a couple years back and mine were definitely off, both from each other as well as the angles they are supposed to be.

Didn't stop me from continuing to use as is, however.

Somehow, I've managed to survive this blow. :p

[Jason Paul]

Thanks all.

Is your table or counter flat? Not that I want to direct your OCD towards how level your surfaces around your home are.

Funny - my OCD is way ahead of you here. That was the first thing I did after seeing the difference in angles. The table I was on was slightly off-level, but that didn't change the difference in angle between the rods themselves. I leveled the table and the differences are still there.

Overall I agree that it's impractical to expect a perfect fit with perfect angles.

I also wonder in the grand scheme of things, with an edge as small as these are, how much difference would 1-2 degrees make?

[anycal]

My Sharpmaker has never been even from day one. That was some years ago. Initially I would prop up one side and level the stone angles that way. Ultimately, I gave up on the system. But still use the tri-angle stones regularly freehand.

[bearfacedkiller]

I think that once you get deep enough into it this device becomes the Spyderco “Microbevelmaker” which is just a more specific way of saying Sharpmaker.

I have done plenty of reprofiling on it but ultimately where it really shines is deburing and maintaining edges through microbevels. In that sense the slight variation in angles shouldn’t matter much.

Also, with the use of a sharpie you will in time just acquire the muscle memory to compensate for any difference while reprofiling.

I love the SM and still use it a ton.

[sal]

Hi Jason,

Welcome to our forum.

sal

[pantagana23]

Edges on the knives are also off almost every time (16-18), sometimes more.
You can force the perfect 15 by reprofiling on a pro machine like some said above, or can freehand follow the existing edge angle, maybe do a 20 microbevel on the Sharpmaker (if you say the angles are off, just use the same rod, but flip the sharpener 180).

[Evil D]

Can you actually hold the knife perfectly at 90 degrees and keep it there throughout the whole range of motion? There's probably more variance in how well we can hold the knife than there is in the Sharpmaker base. It hasn't stopped me from getting amazing edges.

[Wartstein]

Can you actually hold the knife perfectly at 90 degrees and keep it there throughout the whole range of motion? There's probably more variance in how well we can hold the knife than there is in the Sharpmaker base. It hasn't stopped me from getting amazon edges.

They sell edges now?

[Evil D]

Can you actually hold the knife perfectly at 90 degrees and keep it there throughout the whole range of motion? There's probably more variance in how well we can hold the knife than there is in the Sharpmaker base. It hasn't stopped me from getting amazon edges.

They sell edges now?

Doh!

[Jason Paul]

Thanks again for the additional replies, and to Sal for the welcome!

Yeah - I'm sure I'm just overthinking this and became unnecessarily concerned. I mean, Spyderco has probably sold dozens of these things by now. I can't be the first one to have one that was 1-2 degrees wonky.

Considering the variances if I were freehanding, factory edges in general, holding the knife perpendicularly, etc.; there are plenty of ways for a sharpening job to get off by a degree or two.

Thanks again,
Jason