Thread: Help with a grind issue

Do not sweat the center line, just do the same things to both sides it will be close enough. 50 draw files strokes one side then 50 on the other side. Just try to keep it even, your eye is better than you are giving it credit for.

Charlie

I tried to take a picture, but as you can tell, it didn't turn out.

I sighted down the edge several times from both directions. It is as close as I'm going to get it, I fear.

You have a surface plate. Do you also have a precision grinding vice and a height gage? You could clamp spine in vice and use the scribe.

You could also use an angle plate or other "square" block of steel, resting spine on surface plate (so blade points up) and scribe from the square plate and not the surface plate.

Make sense? If not don't sweat the small stuff, eyeball it and call it a learning experience. It will probably turn out better than you think.

Jeff

Originally Posted by TURNMASTER

You have a surface plate. Do you also have a precision grinding vice and a height gage? You could clamp spine in vice and use the scribe.

You could also use an angle plate or other "square" block of steel, resting spine on surface plate (so blade points up) and scribe from the square plate and not the surface plate.

Make sense? If not don't sweat the small stuff, eyeball it and call it a learning experience. It will probably turn out better than you think.

Jeff

Jeff, I had to laugh at your post, but not because of the content. Its because of my woefully inadequate shop. Yes, I have a surface plate, but it's only a $3 piece of marble from Lowe's. I don't have a basic vise, let alone a precision grinding vise and I'm not even sure what a height gauge is. I will have to post a workshop pic in the main WIP thread.

Your post makes sense, in the sense that I understand what you're saying. However, I just eyeballed it as close as I could. If nothing else, it will indeed be a learning experience.

I thought just maybe. I have a very limited shop at home myself. Hand and basic power tools, with a bench grinder and shopsmith. Anything precision I do at work.

Well, I did the filing. Here are some pictures. Not sure if it's worth getting heat treated or not. I may have messed this up.
Edge, front side up:


Spine, front side up:


Edge, reverse side up:


Spine, reverse side up:

You can see where the grind is off on the tip.

I guess I'm stuck now. Shouldn't have tackled a smiling wedge first, the geometry is hell. Scratch it all and make it a western ground kami?
Props provided by Pinky the dolphin, and my daughters.

With a smiling blade the plane that spans between the spine and the edge is not a true flat plane, it is more like a section from a sphere A blade with a big smile will not lay flat on flat surface. You have to use some sort of compensating stroke (like the rolling X) to establish the flats on smiling blade.

I think what you have done so far looks good.

Pinky rocks!

Charlie

So the actual grind isn't flat from spine to edge? Like when I lay a straight edge from the edge to perpendicular to the spine, it shouldn't be flat all the way across at every point along the length of the blade? It is really close, along the order of 1 mm in places it's not perfect, but I wasn't sure. I'll just keep plugging along and sanding it up through the grits then. I'm only going to 800 before HT.

Yes the line is flat in between any given two points going from spine perpendicular to the edge. I can not articulate what I want to say. I am trying to say that the edge of a smiling blade will not touch along its length on a flat surface.

Charlie

If your edge looks straight enough to hone, HT it. We never know until we try something new. If it doesn't work, well, we learn more from our failures than our successes. If it was me I would put it to a hone now just see if it is workable. It may take a bit more to hone but it would be worth HT if possible to hone.

Either way you look at it you win.

Jeff