Knifemakers Scribe

[JUNGIANEINSTEIN]

I finally broke down and ordered a real knifemakers scribe for marking the center lines on my blades from Koval Knife Supply and just wanted to share that any of you out there like me who are brand new to this it is well worth the less than twenty dollars to get this little tool as it is so much better than trying to eyeball it or any other method I have tried.

[Ray Rogers]

There are many methods that can get the job done but none that offer the ease and flexibility of that simple tool. The right tool for the job.....

[John T Wylie Jr]

I bought one of those but can't for the life of me figure out how to set it at the height I want... gonna get me one of the height gauges with the dial indicator on it if I can't figure out how to set it to the height I want accurately :confused:

[Terry Primos]

Vegas Henchman,

Since I forge the blade bevels in, I don't use a scribe. I have to try to hammer the edge centered. But my first three years or so as a maker I strictly used the stock removal method, so I can offer some tips.

Don't even worry yourself trying to make a single line dead center. Just set the scribe somewhere "close" to the center. Scribe a line, then flip the blade over and scribe again.

You'll have two little lines, very close together, that are the same exact distance from their respective sides. It's like a microscopic railroad track running down the edge. The tiny space between the tracks is what's dead center, but that's irrelevant.

As you grind, just make sure that your bevels on each side are the same distance from their respective lines. Your edge will be centered.

[John T Wylie Jr]

I am doing the dbl line railroad tracks but I can't figure for the life of me how to set the height of the scribe to the height I want.....just eye shotting it now. Seems to work though...

[JUNGIANEINSTEIN]

I just mark the halfway point using a ruler and do the railroad track method.

[Ray Rogers]

Terry's method works fine and that's what I do except that I prefer to set the distance between the 'tracks' to some specific value, like .015 or .020 for instance.

Here is a picture of the scribes I use:



The small square on is the one I use to mark the edge of a blade. The carbide point on this tool is exactly 1/16th (.062) in diameter. This means that with the point as close to the body of the scribe as possible the tool will draw a line down the center of a piece of steel that is 1/16th thick. This means that the sharp part of the point is .031 from the edge of the steel and also from the body of the scribe.

For blades thicker than 1/16th (as most are) I set the scribe using an ordinary set of spark plug gapping guages. Slide the required guage between the scribe body and the carbide point and tighten down the screw.

To figure what guage to use, take the thickness of the steel and divide by 2. From that value, subtract .031 (half the diameter of the carbide point). This gives you the thickness of the guage required to put the scribe's point on the exact center of the blade. If you want to create 'tracks' that are, say, .020 apart take .010 (half the track width) off of the guage size previously calculated for the exact center of the blade.

Example:

.187 blade thickness (3/16ths) divided by 2 = .0935

.0935 - .031 (half the carbide point's diameter) = ,0625 (guage required for exact center)

.0625 - .010 (half of .020 track width) = .0525 guage required for two tracks .020 apart

Most spark plug gap sets don't have a .052 guage so use the .025 + the .026 together or any other pair that gets you within a thousandth or so. As Terry indicated, your ability to grind is not precise enough for a thou or two on this measurement to be significant...

[blgoode]

I have a scribe but find calipers work better for me. Easier to adjust too.