Grinding an Arc for the Smoother

[Doug Mason]

For all you old-timers, this is old hat; but for people still learning the ropes w/their planes, like me, this might be interesting. This weekend I took the blades of my Jointer plane and Smoother and and ground them free-hand. I ended up with wavy edges--as evident when I went to hone on a fine oil stone and some parts of the bevel were shinny and others not. But by simultaneously grinding/honing, I was able to get a straight bevel at just under 25 degrees (I build primarily in soft wood at this point)--and the shinny honed edge spanned the entire primary bevel. With practice, hand grinding would not be difficult and with the added benefit of being quick.

For a long time I have accepted the slight edge lines that my smoother would leave from the corners of the blade--even when taking the thinnest of shavings. I had often read that I should arc the corners--so I ground the two corners down a bit (just enough to where I could detect it w/a straight edge) and honed. To get the corners rounded even more, I put some added pressure on each corner as I honed. The result was a shiny honed edge along the majority of the edge, and a barely noticable shine at each corner.

Then I jointed a wide board as flat as I could, and of course I had the edge lines from the corners of the blade. Then I took the Smoother to it, with it set for a fine shave, and there were no edge lines--they were gone. I had never gotten a board this smooth and shinny. The only difficulty I encountered was in determining if I was getting a full-witdh shaving--but it was close enough. So if you have never arced the corners of your Smoother blade,--give it a try:p .

[Jim Grill]

How funny... I just had the exact same experience over the weekend. I had read about rounding the corners but was a bit afraid to do it - no idea why. It works great.

[David Weaver]

All i can say is that I've never had an issue, and here's probably why. I leave the primary bevel straight across - for better or for worse, it's a whole lot easier to do that - especially on something that's going to take very light and hopefully nearly flat cuts like a smoother.

What I *do* do is put the curve on the blade on the two microbevels I do - that way you're not cutting too much metal to do it. It's easier if you count your strokes to do it. That is, pick five spots on the blade, and presumably you're using a honing guide - put your finger pressure on the five different spots.

By five spots, I mean one will be the middle, two others will be the outside corners of the blade, and the last two will be the spots between those two. If you have a good straight edge and you do all five spots with about the same pressure and the same number of strokes for each pair (i.e., the corners are a pair), you'll find out that you have a very gradual curve. On the smoother, you'll want to keep the number of strokes to a lower amount on the corners, like five each.

Remember that you don't have to do much with a fresh grind, only enough on the bevel to raise a wire edge, and you should be able to feel it with your finger nail.

It'll become easy with practice, and as long as you document and use the same angle for each step each time, you won't have to use many strokes on the stone to raise a wire edge - you'll get long life out of your irons.