How to verify that the blade is clamped straight

[Johpe]

Hi there

Have anyone figured out a good way to verify that you have managed to clamp a blade perfectly straight / perpendicular in the vise?

I’m definitely having problems with seeing or verifying this on full flat ground blades. I mean I can look at it and say if it is way off, but if it is tilting with say 1 degree I think it is close to impossible to see this by just looking at the setup.

Since the rest of the WE system (with using the angle cube) is exact down to 0.1 degrees I’m hoping there is someone with a good idea on how to really make sure to clamp the blade straight otherwise that will always be the biggest source of error (at least for me).

I’m using the foam tape trick to help with clamping ffg blades, but even so it is easy to clamp the blade in a way that it leans significantly (which will affect sharpening angle).

//Johannes

[Ken Buzbee]

One thing I do pretty much every time now is take a couple swipes with say a 1000 stone on each side and see how it’s hitting the edge, through a loupe. That seems to help me figure out any mounting issues I may have.

Ken

[Johpe]

One thing I do pretty much every time now is take a couple swipes with say a 1000 stone on each side and see how it’s hitting the edge, through a loupe. That seems to help me figure out any mounting issues I may have.

But if you’re re-profiling or if the edge is already off that wont tell you very much I guess?

[Ken Buzbee]

Well, in both cases, it is still really is helpful to see. I understand your point. Think of it as a point of reference.

Ken

[Geocyclist]

Try this. Hold a flat edge against the blade (if you have space) like metal ruler. Use the angle cube to measure.

Or lay a square on the base and see how it lines up to both sides of the handle.

Haven’t tried this, but it may be possible to use something like an angle finder. You would need a perpendicular line or something on the base to reference against.

[Johpe]

Well, in both cases, it is still really is helpful to see. I understand your point. Think of it as a point of reference.
Ken

I’m guessing it can get good enough by just eye sight, but I’m reluctant to accept that (at least) I would be able to see a 1 degree variation with just the naked eye. (And the 1 degree variation would be the largest source of error in the WEPS, on a 15 degree edge it gives almost 7% error.)

Try this. Hold a flat edge against the blade (if you have space) like metal ruler. Use the angle cube to measure.

I’ve tried this and it works somewhat good on most blades, but on smaller blades like the Spyderco dragonfly or ladybug there is almost no part of the blade sticking out from the clamp to “attach” the ruler/angle cube to.

Or lay a square on the base and see how it lines up to both sides of the handle.

Haven’t tried this, but it may be possible to use something like an angle finder. You would need a perpendicular line or something on the base to reference against.

The two ways you mention here you’ll have to describe a bit better for me… 😉

[Johpe]

Yesterday I was at it again and I think I found a (for me) good enough solution. I’m not interested in how much it tilts (or not) just that it is straight enough.

I started with the metal ruler and the angle cube but that gives me very (relatively) large differences from side to side and time to time just depending on how I hold the ruler against the blade and if it is leaning and so on, not very repeatable.

So what I did was take a fish line and tied sinks (weights) in both ends and then hung it over the blade. If the fish line on one side hangs out from the blade that means the blade is not straight in the clamp. Quite simple (and cheap) and works every time; when both sides of the fish line hangs straight down along the blade I know that I have very little tilt angle on the blade in the clamp.

To explain better what I did I’ve attached the following two images of a blade that is not straight in the clamp (I’ve exaggerated the tilt just so it’s easy to see what I mean).

BR,
Johannes

Attachments:

• weps_straight.jpg
• weps_straight_closeup.jpg

[cbwx34]

Looks like a great innovative approach Johannes.

Thanks for sharing!

[Ken Buzbee]

Looks like a great innovative approach Johannes.

It does, assuming your table & base are basically level. I’ve noticed small variations depending where I set up. By small, I’m saying under 1°. I always zero out my angle cube on the base to compensate, even though it isn’t much.

But say your floor was off a degree, and your table was too, compounding, not correcting 😉 your string will tell you a plumb blade (relative to your WEPS) is off 2°.

Not a problem, just something to keep in mind. We think of horizontal surfaces in our life as being level. Most aren’t quite.

Ken

[Johpe]

It does, assuming your table & base are basically level. I’ve noticed small variations depending where I set up. By small, I’m saying under 1°. I always zero out my angle cube on the base to compensate, even though it isn’t much.

Yeah I thought about this and put the angle cube on both my floor, my table and my WEPS base and there were no major differences there.

It’s also quite easy to verify this by clamping a ruler by it self and putting an angle cube on that and then hanging the fish line over the ruler, then you can see if they match up well.

[R. Jeffrey Coates]

That is a simple and effective solution. The only concern I see is making sure the WEPS is on a level surface. Using the gravity method one is measuring the knife relative to vertical. What one really needs to measure is whether the knife is perpendicular to the WEPS.

Using gravity will show the angle of the knife relative to horizontal (0 degrees) but, the WEPS may or may not be on a level surface. So if the knife is at 90 deg and the WEPS is set on a table with a 2 deg slope the gravity method will show a false 2 deg. error.

What one really wants to measure is the knife to vise angle. Gravity measures the knife to earth angle. For maximum accuracy, all measurements should be taken relative to the WEPS not true 0 degrees.

For example, when I put my WEPS setup on my table and put an angle cube on the base it shows a 0.5 angle. I zero it out and then set my angles.

If you have access to an angle cube I suggest zeroing it out on the WEPS base then setting it against each side of the knife. If the knife is truly perpendicular to the WEPS vise the angles will be equal on each side of the blade. After all, I am not looking for perpendicular to horizontal, I am looking for perpendicular to the WEPS.

[Johpe]

gravity will show the angle of the knife relative to horizontal (0 degrees) but, the WEPS may or may not be on a level surface. So if the knife is at 90 deg and the WEPS is set on a table with a 2 deg slope the gravity method will show a false 2 deg. error.

What one really wants to measure is the knife to vise angle. Gravity measures the knife to earth angle. For maximum accuracy, all measurements should be taken relative to the WEPS not true 0 degrees.

Absolutely, just as I wrote in my post just before yours I have verified my setup in two different ways to make sure that my table and WEPS are horizontal.

[Author]

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