Blade Angle Finder

[grepper]

... and may enable to estimate the bevel angle of a very short microbevel also. This is challenging even for laser goniometer.

Mr. Jan, Why?  Is it because the beam is not focused enough on inexpensive lasers?  If I remember correctly, you applied an external lens to focus yours better.

What power laser to use?  Obviously you should not have to wear safety glasses.

[Jan]

Yes, Mr. Grepper, very short microbevel does not reflect enough laser light to form clear line or dot on the cross board. The primary reason is the fact, that the laser beam width is often much larger than the microbevel. My experience is limited to inexpensive laser modules which are not fully focusable. 

I am using 5 mW line laser modules while Catra uses dot laser modules of the same or smaller output power.

I do not use safety glasses, I think the laser goniometer is more safety than a pointer during a presentation.

[Edgepal]

Jan,

Yes my sharpening tool Chef are very exact and can be adjusted down to 1/100 part of 1 degree. (An Angle Cube shows +/- 10/100 parts of 1 degree).

Chef use screws and nuts to adjust the angle. 7 full turns of the nut give 1 degree. 1/7 turn of the nut give 1/100 part of 1 degree. Chef works like a degree meassuring "instrument" and are very exact. The nuts have markings so it is easy to count turns or part of turns.

It is possible to go between two different surfaces (bevels) and hit the surfaces exact.

On my homepage can you se how I have made different bevels on two knifes, one of the knifes have three bevels, 9, 10 and 11 degrees, the other knife have five bevels, there is 0.75 degrees between the bevels, the bevels are around 1 mm wide and they are straight from the handle out ro the tip.

A third picture shows a knife where I have grinded an edge absolutley flat and then made a second bevel that is 1/100 part of 1 degree higher. I have made the scrathes diagonal in different directions so it is possible to se what I have done.

This is made with a Chef with pivot - and anyone that have a Chef can do this. No extra equipment are necesarry.

In my mind it is nice to be able ro meassuring degrees on blades with the sharpening tool. Two functions make this possible, the possibillitiy to adjust for different blade width opens the possibilitiy to attatch a protractor and that opens the possibility to allways use a fixed distance between the edge and the pivot point of 28 cm (on Chef).

Thomas

[Rupert Lucius]

Mr. Thomas, thanks for mentioning your approach! In my understanding your angle measurements are quite precise and may enable to estimate the bevel angle of a very short microbevel also. This is challenging even for laser goniometer.

Thomas's (Edge Pal) Chef method may be the best for me.  Most of my knives the bevels are short - none of the knives are thicker than  -  1.5 mm/1.8 mm).  Therefore the bevels are short.  My eyes see the black ink,  blends as part of the metal - a fellow sharpener said RED ink works for him - it does for me to.

Using the Tormek angle master WM 200 on any knife thick or thin I usually go by the senses of feel and sound to determine where to lock the set.

For the price of a decent Catra goniometer 600.00$ +/- one can purchase the Chef that serves several functions.

The vernier protractor is very accurate - my bevels are short?

Thomas's bevels can be flat?  Tormek bevels are concave?  Belt bevels off the platen are convex?  The convex bevel, how do we determine what degree it is?  Like a rocker on a rocking chair. Do we describe it as something other than degrees?  This may be where the goniometer paints a picture for us?

Jan - I only know how to do add, subtract, multiply and divide.

Thanks

Rupert

[Edgepal]

Rupert, Chef can meassure also convex edges angles. Both what angle there is on the cutting edge - and how many degrees there is on the convex sphere. It is not as easy as on flat edges - but it is still simple to do.

To se what really happens in degrees it is possible to use a Angle Cube placed on the sharpener holder, angle Cube then shows how the angle changes when you move the sharpener forward and back across the edge. (I sont need to use a AngleCube, but it is nice to se how the angle changes when you use Chefs angled guide rod).

1 degree change = 25 mm (1") use of the sharpeners length. 2 degree = 50mm (2"), and so on. A 10 cm long sharpener gives 4 degree convex sphere. The springs and the stop nuts who comes with Chef are used to fix the distance used on the sharpener = fix the convex sphere degrees.

I decide how I like to have the convex sphere and what angle I like to have on the convex cutting edge and adjust Chef to this - and I get on the edge what I have adjust Chef to do. It is very simple to do - and of cause, I can repeat it when ever I like. Maintainence sharpening are easy to do and it dont change the edge at all.

Chef is the only sharpening tool that can make, and maintain, perfect true convex edges in any wanted degrees.

I invented the method to grind and sharpen convex edges for many years ago, first I used a bended guide rod and I use it also today with my tool AcePal, then I use an angled guide rod as with Chef and Forest.

Chef are a very advanced sharpening tool.... And the only tool that can make true convex edges in degrees.

Allready my first sharpening tool "Edge" could sharpen both flat and convex edges

Thomas

[grepper]

Mr Jan, Any idea it this thing is a better focus than what you are using? I know, you probably can't really tell just by looking at the web site.

It can focus the beam enough to light matches, whatever that means. (I know nothing about lasers).

[Jan]

Thomas's (Edge Pal) Chef method may be the best for me.  Most of my knives the bevels are short - none of the knives are thicker than  -  1.5 mm/1.8 mm).  Therefore the bevels are short.  My eyes see the black ink,  blends as part of the metal - a fellow sharpener said RED ink works for him - it does for me to.

Using the Tormek angle master WM 200 on any knife thick or thin I usually go by the senses of feel and sound to determine where to lock the set.

For the price of a decent Catra goniometer 600.00$ +/- one can purchase the Chef that serves several functions.

The vernier protractor is very accurate - my bevels are short?

Jan - I only know how to do add, subtract, multiply and divide.

Mr. Rupert, in my thinking really short microbevels are below 0.5 mm*. Your bevels should be measurable with Vernier bevel protractor, which is not an expensive tool. Use good bright light.

As you have mentioned, knife bevels may be flat, concave or convex. Most important for the knife performance is the angle and thickness at the cutting edge, so I recommend to measure the edge angle here.

Mr. Rupert: If you add to the + - * / operations the law of reflection, which is know from billiard, you are fully qualified for the most precise optical angle measurements.

   

*P.S.: The attached image shows a 0.1 mm microbevel on a new Morakniv. This is an example of very short microbevel. I was very happy when the knife manufacturer confirmed that the blades were shaped approximately with these parameters.

   

[Jan]

Mr Jan, Any idea it this thing is a better focus than what you are using?  I know, you probably can't really tell just by looking at the web site.  

It can focus the beam enough to light matches, whatever that means.  (I know nothing about lasers).

Mr. Grepper, all you need to know is that laser is a diode emitting a narrow beam of colored light (red, blue or green). In US the power of laser pointers is restricted to 5 mW for safety reasons. It means that the energy consumption is very small and may be powered from battery for years.

For bevels not shorter than some 0.5 mm with reasonably good finish also the inexpensive laser modules provide quite good results. If the reflections are weak you can make the measurement in a darkened room.

Laser pointers are often used to illuminate distant objects with small bright spot. The laser beam is invisible in clean air, but when used on larger distances the laser beam scatters on dust in the air or on water droplets which makes the whole beam path visible. It is recommended to have it in an emergency kit.

   

[grepper]

Doh! Forgot to post the link. You can focus this one:
https://www.amazon.com/Focusable-650nm-M...B00S1EXW3Y

In the US maybe laser pointers are limited to 5mW, but dangerous, high power laser are also available. Check out the list on the left of the page:
http://www.laserpointerpro.com/attribute...w-lasers_2

[Jan]

I use similar module as shown in your first link. It is good to have one line module and one dot module for experimenting.

You simply connect the wires of the module via a small switch to a 3V battery and that's all.

You are correct, for steel engraving, laser modules with several thousands of mW are used.