Thread: Managing Tear Out and related concepts

Originally Posted by Horaldic

.......Will a steeper frog angle help in cranky, hard, interlocking grain? My answer is maybe, but I’d still try a standard angled plane first. Most importantly though if the iron isn’t sharp then you’re wasting your time. After that any number of things might work. Given the massive variety of timber and grain it’s very situationally dependent......

That pretty-well sums up my attitude, too.

I spent much of my working life staring down a microscope, so thinking of cellular structure is second nature to me but I think you are right in suggesting that a good grasp of what a piece of wood actually consists of can be helpful in understanding & predicting how it might respond to being attacked with any cutting tool. Hoadley & Bootle are both well worth a read, in fact every woodworker in our Wide Brown Land should endeavor to get their hands on a copy of Bootle's book.

And the caveat I always make - some bits of wood just refuse to be planed with any cutting angle or chip-breaker setting that I can bring to bear, so if these must be wrestled into submission, it's out with the scrapers and abrasives. But when you are starting out, I think it's wise to stick with the more 'traditional' cabinet woods, or at least woods that are known to be generally workable with planes of common pitch, chisels that aren't on the dimond scale of hardness, etc. A careful choice of raw material can save much sweat & heartache!

Cheers,

Well, first off, this is a great post. I really appreciate the way you frame it as "this has been my experience" as opposed to "this is how it is".

Ultimately, I don't have much to add, because I pretty much agree with and share the experience which precedes everything you've said.

I am a big advocate of the cap iron. I think that sharpening the tool is the obvious first step in preventing tearout. Nothing else matters if the blade is blunt.

In my experience, after you've sharpened the blade, if that is not enough then the next most effective thing to do is to steepen the angle of attack. Steeper bedding angles is one way to do it, but I've become an outspoken advocate of the cap iron because it allows you to take an existing (and often quite cheap) Bailey style plane and turn it into an almost "skeleton key" for unlocking effective smoothing.

I'll give an example, and I hope IanW doesn't mind me naming him here. Ian and I made a workbench together in 2015 out of Eucalyptus tereticornis. Blue Gum in Queensland and Forest Red Gum everywhere else. Of all of the woods I've ever worked by hand, this has got to be the most cantankerous w.r.t. tearout. When we were building this bench, we were using Bailey style planes and we were always fighting an uphill battle to keep the stuff from tearing out on the rowed/radially sawn grain out on the edges of the boards. When we ultimately called it done, I did quite a bit of scraping on it before finishing it.

Earlier this month, after two and a half years of drying out, an international move, and a relocation into a climate controlled shop in Seattle, USA from an open air shop in Brisbane, the top had to be flattened. This required a lot of planing across the grain, during which there was no tearout, and then finally planing along the grain of the 8ft monstrosity. I used a 5 1/2 Stanley to remove the cross-grain marks, and there was tearout. I then used a No. 7 to remove the last of the undulations and there was also tearout.

To this point, all was in alignment with my experience with Ian. I used my planes without the cap iron engaged, and, even though they were sharp, they still tore out, because... well, "because Blue Gum".

The real proof in the pudding was when I went to use the smoother. We didn't initially smooth the bench in '15, so I took it home and smoothed it there. I used my Stanley No. 4, but this was before I knew about the cap iron, and, as mentioned above, I had to do a lot of scraping to really get rid of all the torn out grain. This time, I had the cap iron engaged, and I was able to smooth the entire bench, even a particularly nasty section with crotch material, without tearout. I stopped half way through to sharpen, but that's just par for the course with this wood.

So that experience really solidified my stance on the matter of cap irons and steeper planing angles.

Anyway, that's just an anecdote to add something to your already very thorough and thoughtful post.

Cheers,
Luke

An excellent summary of the cap iron.

Sometimes, wood is so bad that you'll only get tearout free or close to it with the smoother. With the heavier planes (jointer, whatever), the balance point of good function is a little bit of tearout, but not so much that the plane comes out of the cut or bucks you around while planing. That's maybe true for dimensioning in general - the point where you allow just a little is easier than allowing none, and far easier than allowing a whole bunch.

I think you've mastered it.

And, of course, there is wood that won't be planed at all. It's rare, but you find it sometimes. Nobody would generally build anything from wood like that to begin with, so it's more of a hypothetical issue (it usually corresponds with terrible chiseling and sawing due to brittle bits or terrible grain orientation or runout) most of the time than anything else. The hard wood with very weak earlywood (which is most of that type) doesn't wear well in the first place, so the reward for all of that work is a made item that isn't nearly as durable as its hardness would suggest.

There's also the truth that wood running directly into a cap iron at an angle similar to the bedding angle of a plane just will not plane to a shine. that happens with runout. It usually won't scrape to a shine, either, if it won't plane to one. Sanding is the only fix. Sometimes the slight difference enhances figure (curly cherry comes to mind) and it's desirable because you're going to cover it with a finish, anyway, and the difference in tactile feel (different than gouges from tearout) will never be noticed.