I've been reading about using buffing wheels as the final step in honing/polishing a plane or chisel and there is always discussion about "rounding off the bevel" and it's implied that this is bad. What exactly does that mean, how does it happen, and what's bad about it?
Thanks.
Charles
It means that you 'round off the bevel', it happens when too much time/ pressure/agression is used on the wheel and because the wheel isn't a flat plane, and it dulls the blade you worked so hard to get sharp. The final steps in sharpening are tiny adjustments and power tools are not needed.
R
Strops made of hard felt, or leather over disks charged with fine compound do a great job on an edge. You strop with the wheel running away from the edge and don't press the tool into the compound/surface, and you won't round over.
Whether or not you need a stropped edge on a plane iron is up to you. On a chisel, never. OTOH, carving tools designed for hand power benefit greatly.
Better to sharpen, buff to polish that surface and then return to the stone, increase the grind angle 1 - 2 degrees and create a micro bevel by making "1" or "2" passes, no more. The polished edge decreases friction on the larger surfaces that come in contact with the wood. The micro bevel is very small, typically 1/64" -
1/32" in width and does not create much drag. Then a return trip to the buffing wheel for a "moment" to remove the wire edge created when grinding the micro bevel.
The kind of buffing wheel you use for this is called a "hard felt buff" and it is very dense almost as hard as a piece of wood. When you round the edge over you increase the force needed to use the tool, not good. With a hard felt buff and compound you can deburr,hone and microbevel in one pass. A good hard felt buff is $40 us or more for 6"
It does not matter how sharp the tool is if the cutting edge itself is not the first part of the tool to contact the work.
Daily Grind
Depends on what type of wheel and compound you use. Only black, brown and white will take off metal. Red and blue will definately just polish. There's a good guide to polishing metal at
Basically, it means you're changing the edge from a V shape to a U shape. Ideally, a buffing wheel that's "charged" with honing compound can put a very nice final polish on edge tools, and polish out the tiny scratches left by your finest sharpening stone, leaving the edge even sharper. However, it's relatively easy to actually make the edge worse on a buffing wheel - rounding over occurs if you hold the blade against the wheel for too long or if you hold it at the wrong angle.
You can achieve a similar effect by "stropping" on a piece of thick, hard leather that's been charged with honing compound. Set the leather on a flat surface, and hone the blade with a motions that lead away from the cutting edge. In other words, you shouldn't be using a shaving motion that would let the blade gouge the leather - push or pull it the other direction. I prefer this as I feel like I have more control, and it moves slower than a power wheel so you can't mess it up as quickly.
Hope this helps, Andy
Try to *lightly* buff about 1/8" back from the edge. The wheel will depress just enough to strop the actual edge without taking it out of flat. If it does go out of flat, a couple of strokes across your fine stone will fix it.
A Tormek does the same.
You can also use a scrap piece of MDF charged with honing compound to strop the knife. Sounds funny but it works very well.
Chrome green watercolor on a strip of plywood.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.