Popular Woodworking 2008-10 № 171, страница 52

Be\el-upcan help. AN three of these toots haw the & bevels facing up. This fact nukes them easy to configure to a high angk' of attack, tt just takes a little sharpening

Rick sinstructor wusgcttingat. When it comes to reducing tear-out ,c»nc of the most important weapons istheangleof the tool'scuitcr-a.k.a the "angle of attack." And no other tool gets you to a high planing angle as easily.

The higher the angle of attack, the less likely the wood fibers will lift up and tear out. Sounds good, right?What's the catch?

The only practical downside toa high angle of attack is that the tool is harder to push. And that's not too much of a factor when your shavings arc tissue-thin. Plus, the high angle of attack works great wu h well-behaved hardwoods, too.

So what docs the Veritas plane have todo with the angle of attack? After all, its cutter seems shinga lot lower than the cutter on a traditional plane. Well, the difference isthat the Veritas (and some ot her block-plane-like tools such as the Lie-Nielsen No. 164) work with the cutter's bevel facingup. while traditional planes cut with the bevel facing down.

This makes a huge difference.

Inatraditionalplanc withthebevel facing down, the angle of attack isalmost always set by the frog(thecastingthat holds the cutter). In almost all vintage metal planes, this angle is 45° (new planes by Lie-Nielsen let you pick a 50° or 55° frog, however).

When you flip the cutter over, the angle the bevel issharpened at comesintothe equation when figuring out the angle of attack. Here's

how: The cutter in a bevel-up plane is usually bedded at 12° or 20° to the sole of the plane. Let's use 12° for our example. I f you sharpen the cutter so it has a 30® microbevel on it, ihen you add t he angle of t he bed (12°) to the angle sharpened on your cutter (30°) to get the angle of attack (42°).

So this configuration would make a bevel-up plane behave much like a t radit ional bevel-down plane - or perhaps even a bit worse.

But ifyou sharpen the cutter at 45° instead of 30°, then the world changes. You add the 45° to the 12° and suddenly you have an angle of attack that is 57°-that's fairly steep. And you can achieve that angle (and remove it) with just one quick sharpening.

Sowhat'sthc best angle of attack forgnariy woods? I've found that with almost all woods, tear-out tends to disappear with a 62° angle of attack-that means sharpeninga 50° bevel on your cutter and putting it on a 12° bed in our example.

Ifyou have a bevel-down plane, you get to this high angle by sharpening your iron with a knife edge, which is more work.

No. 5: Button Your Lip 1 have held (and used) three of Kari Holtey's revolutionary No. 98 planes. The first thing you notice about these tools is that they are flawless. Holtey lavishes attention on his planes like Gollum on the Precious. Every

surface, inside and out. is perfect. Once you take that in, the next thing you notice isthe non-adjustable mouth of the tool. It is, by most tool snob standards, bigenough to drive a scrub plane shaving through What gives?

Tofindout. 1 sharpeneduptwoplanes. My trusty Lie-Nielsen No. 4 with a 50° frog and a mouth aperture between .002" and .0025* wide. Then 1 sharpened up the Holtey so its angle of attack was also 50°. Then I took a board of nasty, suriyjatoha (it's almost as mean as coconut) and planed it with both tools. Then I turned that board around and planed it against the grain with both tools.

1 know this board, and it's about as bad a board as I ever want to work. Most standard-pitch planes tear it out. But boththc Holtey and the Lk-Nidscnclcancd it up with no problems - bot h wit h t he grain and against the grain.

This little experiment calls intoquestion the plane snob's obsession with tiny mouth apertures. (By the way. I'm the chapter president of the local plane snob club.) After planing that Jatoba, 1 had to ask myself: Doyou need a fine mouth for high-tolerance work?

I think the answer is: It depends. I think tightening up the mouth aperture of your plane is just one of the weapons you have in your battle against tear-out. But I don't think it's the doomsday weapon.

The long-held theory about the plane's mouth is that a small aperture is preferred

A mini-mouth. Tightening up the mouth aperture of )<xif plane can help in some cases, but you are likely ro increase the chance of clogging up the i sorts.

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