scribing the middle

R

rhettfcr

Joined
Oct 8, 2002
Messages
28
I looked at a website and saw how to make your own centering tool. The instructions said to take a 2"X2" block of wood, drill a 1/8" hole near the bottom and secure a carbide tip. Next was to drill a hole for a 1 1/2" 1/4 20 carriage bolt. The site mentions that measuring is not important. I understand the concept but how do you adjust for finding the center of the blade? I realize that you will have two lines, top and bottom but without measuring(which is stated on the webpage)how do you find the middle?

rhettfcr
 
Are you talking about the center point of the edge (to be) of the knife, where the grind lines converge? If yes, I use my edge marking tool along on both sides of the flats which puts two parallel lines on the edge. The tool is adjustable so the distance between the lines can be varied. I think this works better than having one line in the middle, although the lines are so close that they almost appear as one.
 
Here's the scribe I built. I used a block of aluminum, but you could use a thick piece of wood. This one is adjustable for heigth.

The point is a scribe point, epoxied into the slot on a bolt head.

scribe.jpg


For measuring I used to use a caliper and then set the heigth using a sparkplug gap tool. However, I don't measure anymore. Just like RARanney said, if you set it close by eye, and then mark from both sides of the blade you'll see the center just fine between the 2 parallel lines.

Steve
 
I use a dial height gage. You can pay a very large amount for top name brands or you can get one like mine from Enco for 60 - 80 bucks. I can't remember exactly. It is extremely accurate and can be used for marking tang tapers, whatever up to about 12 inches high. You should also get a small comparison block too whether you use what I do or build your own. They are typically flat to within a couple 1/10,000 of an inch and don't cost very much depending on name brand verses house brand. It took me my first four knives before it ever occured to me to scribe an edge line. My dial height gage was sitting there the whole time! What a time saver it is to scribe the line.

Roger
 
Alain's is cooler than mine. :cool:

My excuse is that I don't have a tap and die set.:p

Steve
 
I've had some success using an appropriate size drill bit to mark the
two parallel lines. I simply lay the bit on a flat surface and draw the edge of the profiled blade along bit tip. Not very sophisticated, but it gets me close enough.

Cheers
>> DeWayne <<
 
I got a charge out of the collection of scribes at Steve's original thread (even added my own :) ). For what it's worth, I also apply that Loveless technique of grinding a 45 deg chamfer along the edge right up to the scribed line. In addition to saving you from stripping all the grit off your lovely expensive fresh new 60 grit belt, it gives you a much better visual cue when you're nearing the line than just the line itself. Some days I really enjoy grinding, and some days it's a ... no, I won't say it. Some days I don't.

:D

Dave
 
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