Removing small nicks and sharpening on a belt grinder

D

Dago Red

Joined
Jun 16, 2008
Messages
987
Hey guys,

I know there are countless threads on belt grinders, and I have read them and some have conflicting information, tons of different ideas etc. I'll try and make this concise in the hopes that asking in the axe forum will get me the answers I need.

First, my setup. I have a coote 2x72 belt grinder 8" wheel if I remember right (I have access to a much bigger belt grinder but think it would be overkill). I am thinking from reading that I am going to sharpen on the wheel, edge facing same direction belt is moving (down/away from me).

so here's my questions:
1. if there are small nicks, should I go across the face till it's all smooth and then redo the bevel or should I just keep sharpening till they disappear?
2. what grit should I start with and what grit finish with?
3. I don't have any way to hold an angle, so will have to eye ball it (unless somebody has a device I can make/buy? that said, what angle should I "try" for on an axe?

last question, should I be going for shaving sharp or aren't axes not supposed to be so sharp because they're for chopping?

Thanks all. I have a few older axes I want to get into shape and would like to start getting more, just for fun.

Red
 
If you really want to work on axes, you're going to have to step your game up. I'm thinking like a 8x107. I'm kidding, of course.

1. When I reprofile a head due to chips, I usually take a sharpie and draw my new line that I will grind the edge to. I shade all the area that I plan to remove. Then I take my time looking at it to make sure I like the shape, and determining how I can save the most steel from becoming dust. Once I have my final profile drawn and decided on, I grind the edge flat to my line. Then I do the bevels. I think that's the easier way to do it.
2. I guess grit wise it depends on how much you're grinding off. If it's very much, I'd just go all the way to a 36. The courser the grit is, the less heat that will be created (not to mention being much faster). The grit you finish with is totally dependent on how you want it to look. Anything 150 or finer can give you a serviceable edge for an axe just depending on what you want to do with it. You can get a nice, smooth satin finish with say 400-600.
3. You should be going for a nice even convex bit. For the most part, only some racing axes are flat ground at a certain angle. My personal favorite way to grind a nice convex axe bit is on the slack belt, somewhere around 7-10" of slack depending on the tightness of the belt. I usually do this with the edge away from the direction of the belt, because a few times I've cut a belt when facing the bit into the belt. Scares the crud out of me every time. I still face it into the belt sometimes though, just very carefully. With the edge facing away from the belt travel, you will have a harder time reducing the burr (or wire edge) as you work down to a finish. I finish sharpen by hand anyway, so it's not a big deal.

If you grind on the wheel, keeping it moving and use light pressure so that you don't create indentations in your bit. The more padded your contact wheel is, the less tendency it will have to create indentations.

I like axes to be very sharp, but not all things are equal. An axe used primarily for splitting can benefit from being very sharp, but shouldn't be very thin. An axe exclusively for felling should be thin and razor sharp. My average, multi-purpose axe will shave hairs, but is not overly thin. I guess just keep the purpose in mind as you shape the bit. Sharpness and bit thickness are two different things. Any axe will cut better the sharper it is. The shape of the bit is the key factor in balancing strength with ease of penetration.

I hope that helps in some way.
 
M3, Nice job sharing your thoughts and your profiling/sharpening techniques with the OP. You have sure given him good advice.
The rest will have to come from actual trial and experience from the OP. Yes, I have messed up an axe or two experimenting, thank god they were
garage sale finds. That's how one learns.

My regards, Double Ott
 
Another thing I'll add. As you grind your bevels, frequently look straight at the flat edge you created. Make sure that you are grinding evenly as you go. If you see spots where the flat edge is narrower or wider, adjust accordingly. Also make sure that the line is straight. By the time you get down to a fine edge, it is MUCH more difficult to tell if you are grinding an even, straight bit.
 
Very good advice, M3mphis.

M3mphis said:
Another thing I'll add. As you grind your bevels, frequently look straight at the flat edge you created. Make sure that you are grinding evenly as you go. If you see spots where the flat edge is narrower or wider, adjust accordingly.
Click to expand...


That's an important point. If you don't want the edge to have a wave in it then you need to keep an eye on it during re-shaping.
 
Very good explanation! very much appreciated. What do you do your final hand sharpening with, stones I'm guessing? ONe of those pucks I've seen? I have some stones, I wonder if I could use the hone I have for straight razors, on the courser side, or would it be too fine after going from a 400-600grit belt?

The other grinder I have access to (in my uncle's shop) is I think 2x105 or something, custom made belts, it's made so guys can work off the wheel at either end, it was from his machine shop when he was building paving machines. needless to say we do almost everything on my smaller grinder :)

Red
 
Dago Red said:
Very good explanation! very much appreciated. What do you do your final hand sharpening with, stones I'm guessing? ONe of those pucks I've seen? I have some stones, I wonder if I could use the hone I have for straight razors, on the courser side, or would it be too fine after going from a 400-600grit belt?

The other grinder I have access to (in my uncle's shop) is I think 2x105 or something, custom made belts, it's made so guys can work off the wheel at either end, it was from his machine shop when he was building paving machines. needless to say we do almost everything on my smaller grinder :)

Red
Click to expand...

Geez, a 2x72 wasn't enough, huh? Sounds like a beast. I bet the belts cost a pretty penny.

My dad has a 2x72 that we built. I actually don't use it all that often. Most of my axe work is by hand. However, if I use the grinder on bevels, I finish sharpen with sheets of sandpaper on top of a mouse pad taped down to the work bench. Then I strop on loaded leather.

Turley has a great video on sharpening a convex edge with sandpaper and a mouse pad. It is about sharpening a knife, but it's the same process. Watch it here: http://www.youtube.com/watch?v=8qlM2JDJkQY
 
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