How to tell what is the factory bevel angle?

bladeprince

bladeprince

Joined
Jun 12, 2006
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Is there a trick to finding out what is the angle of the factory bevel? For example, I just grabbed a very nice used Sebenza off of Ebay. Being used, I sure didn't buy it to just sick it in the display case. I bought it to use it (it was easier that way then to buy a pretty new one and then use it..and cheaper too).

I want to touch up the blade but I don't know whether to use the 30 degree or 40 degree angle on my Sharpmaker? If someone just happens to know about the Sebenza, that's great. I'll take that info. But I'd also like to know if there is a "trick" to figuring it out.

Regards and Thanks
 
i think there's some way of simply measuring it up, but i don't have a clue how, and i bet it's pretty tedious too

if you got sharpening-rigs, like your sharpmaker, or a lansky, or whatever. then you try different edge-angle settings and see which one matches the most.

once you get a real keen eye on this it seems that you can tell just by looking at it. ( :eek: ). i'm not that good at it yet, alas. ;)

good luck,

denn
 
Easiest way to tell the current blade angle is to use a Sharpie magic marker on the edge. Take soft swipes on a fine hone to start until you see what part of the blackened edge is removed; adjust as you go.
 
This method relies on using a scientific calculator with trig functions (sin-1 function) and two measurements.

Start with the blade flat on a piece of leather. Slowly push the blade forward while raising the blade spine until the blade bites into the leather. Take the following measurements:
- Elevation from leather surface to CENTER of blade spine.
- Blade spine-to-edge dimension.

Using your scientific calculator:
- Divide (elevation) by (spine-to-edge) to determine sin value of the angle.
- Use sin-1 function to determine the angle in degrees.

This will be the effective single-bevel angle for the side measured. Total included angle should be twice that angle.

Hope this helps!
 
Measure the thickness and width and do the trig calculation, or just approximate it by the 1:60 rule.

-Cliff
 
What units should the elevation and the spine to edge measurements be in? Or does it matter? Also, what would you recommend for taking these measurements?
 
The measurement units don't matter - so long as the same units are used for both measurements.

Doesn't matter whether you use a caliper or rule. The more accurate your measurements, the more accurate the calculated angle. The spine lift-off measurement is probably easier to take with a rule than a caliper.

Hope this helps!
 
Being lazy, I just use waterstones. You can rock the blade and feel a little "click" when the bevel is flat on the stone, and on clay stones you can tell by the way the water wells out from under the edge when you've hit the correct angle.

If you really want to know the numerical angle, they also make these little dial protractors that are about 2" square for about $10... they have a magnet on one side so you can stick it on a flat part of the blade and a weighted needle that will read the angle directly off the dial once you get the blade to click into place on the stone.
 
yuzuha said:
If you really want to know the numerical angle, they also make these little dial protractors that are about 2" square for about $10... they have a magnet on one side so you can stick it on a flat part of the blade and a weighted needle that will read the angle directly off the dial once you get the blade to click into place on the stone.
Click to expand...
By any chance have you got a link for this little gizmo?

Thanks. :)
 
Cool device, essentially a stick-on inclinometer.

It depends on how accurately you want to read the angle. The angle indicated by the inclinometer will always be a bit lower than the true angle, due to the triangular cross-section of the typical blade - since the inclinometer is attached to the underside of the blade.

This thread is entirely too nerdy!
 
I use a micrometer, and take several measurements along the edge. I measure the width at the top of the edge bevel (divide by 2 and you have the "opposite" side of your triangle), and the the length of the edge grind from the top of the edge bevel to the very edge at that point (which becomes the hypotnuse of your triangle). Do that for several sections, use your trig, and average. Arcsin((edgebevel/2)/edge height) is the calculation (I hope I didn't screw that up, it's late). It can be a bit tricky to get the measurements accurately, but with practice becomes easier.
 
Does't mean we're bad people.:D

Nerds like knives too.:D :D
 
To measure the angle at the very edge, I slide the edge along the edge of a piece of paper till it grabs, I line up a ruler along the blade and draw along the ruler. You can measure the angle between the edge of the paper and the line. You have to take into account any angle of the blade grind if you do not have a flat part on the blade to line up the the ruler on, but you can do that by trig.
 
Hi- I use a Richard Kell angle gauge, which is just a brass disc with angles from 15
degrees to 120 degrees cut into the perimeter. I think I got mine from Garrett-Wade.
Cheap and effective. For angles of less than fifteen degrees you'd need something else,
but I never go below 25 on my (woodworking) tools. :-)
 
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