Plane Iron Bevel Grinding

Re: Plane Iron Bevel Grinding

Joel

>When I am done grinding I have a hollow along the entire bevel. I will then hone - freehand - placing the bevel, with it's hollow flat on the stone. What I get when I am done honing is two very small flats at the top and edge of the hollow. THe only flat I am really concerned with is of course the one at the edge or the hollow and blade. The flat at the top of the bevel is formed simply because the entire bevel is flat on the stone. THe flat that the edge is usally no more than 1/64" or so the first time the iron is honed (maybe a little more if the iron wasn't evenly ground). With each honing the flat will grow until the hollow disappears. I will put a microbevel on the edge - but that is only a few thousands wide.

for a typical 2" iron grinding will usually take uner two minutes and honing under 90 seconds.

Re: Plane Iron Bevel Grinding

Adam Cherubini

>The trick to these forums can be figuring out what the question really is. Joel's reading into your post as I usually would. I'll try answering the questions you asked:

My question is does hollow gringing affect how a plane iron, either thick or thin, handles/

I think the quick answer is it doesn't. The longer answer is really a bunch of engineers BSing. If it was a chisel you were grinding this engineer would say the hollow grind makes the edge weaker. Depending on the tool or your use of it, this could well be BS.

If one must sharpen to a mirror finish, then why hollow grind?

Starting with a mirror finish (with a dull blunted edge) and making mirro edge that's sharp is the trick. So we sometimes grind sharp, then hone until we get the mirror.

Is it perhaps possible to short circuit this by honing a small bevel at the tip?

My heavens yes! I suspect this is what guys used to do. The bevel we talk about may have been nothing more than a meaningless relief angle. When the microbevel grew to an inconveniently large size, it could have been simply dressed off on a coarse stone or grinder and the fine edge reestablished.

I'm not sure why we don't do that now. I think you're questions deserve more consideration. Back to BSing. This faceted or convex shape is stronger on paper to either a single bevel with a steeper angle or a hollow grind or concave shape.

Good questions,

Adam