Monday, May 24, 2010

Taking Adam Cherubini's Challenge

There's a thread on the Sawmill Creek Neanderthal Haven forum discussing Adam Cherubini's blog post "Improving Planes". While he doesn't say it directly, they took it as a challenge from him to try using wooden planes instead of modern metal-bodied ones. I've enjoyed using wooden rabbet and molding planes briefly, so I decided to take the challenge whole hog.


The test subjects. I've been accumulating these over the past year.


The soles are all in reasonable shape. The coffin smoother lower left has had a mouth repair.


The irons and chip breakers are also in reasonable shape under the rust. Except...


First casualty: the iron on the wooden jack has already been ground down so far there's not enough left to camber it and reassemble the chip breaker.

Unfortunately, the short iron put the jack out of commission until I could find a replacement. That was the one I was most looking forward to trying, since Adam's post was primarily about using a jack plane for fast stock removal.

As I prepared the remaining irons, I discovered another problem. When I sharpened the iron of the cute little smoother and tried it out, I noticed plane tracks in the middle of the cut. Huh? Examining the edge, I could see where a notch had chipped out.

I resharpened it, same result. Closer inspection with a magnifier revealed tiny hairline cracks throughout the metal, only visible once I had polished the bevel. Now I was down two.

I had already cambered the iron on the transitional jack last fall to use building my workbench, so I tried it here. I had put an aggressive 4" radius on it for roughing down Southern Yellow Pine.

For this test, I set the iron to the maximum depth allowed by the camber, a little over 1/16". Adam's criteria was to get at least .060" shavings in order to  take a board down in thickness by 1/8" quickly. In his Coarse, Medium, and Fine DVD, Chris Schwarz mentions setting up for 30 thousandths. Since 1/8" is .125", in round numbers 1/16" is about .060", so I was in Adam's ballpark.


Wow! This isn't a plane, it's a wood-chipper! I took a chamfering pass down the far edge to reduce spelching, then took steep diagonal cuts.

I took a piece of SYP down by 1/8" in less than 30 seconds. It's so fast you have to be careful you don't overdo it. You also have to watch for heavy tearout and chipping of the far edge (spelching). So it's probably worth backing off the depth a bit after the bulk has been removed.


Big, meaty chips flying all over the bench.


Here you can see the heavy camber and depth. That mouth needs to be wide open.


Right at Adam's minimum requirement.


The cambered iron.

Of course, anyone can look good on soft pine. Next I tried it on oak. A couple of quick swipes across the grain showed that the iron needed to be backed off. It was catching heavily and the plane was bouncing across. I took it down to about half it's previous depth.


It worked just as well on the oak, just took an extra 30 seconds with the reduced depth of cut.


The oak shavings are a little over 30 thousandths, so about 1/32". That means four passes to take off 1/8".


The oak took it's toll on the edge. Not seriously damaged, but roughed up.

I picked up some new test subjects at Brimfield. I got a shorter jointer, equal in length to a Stanley #7, and two jacks, to be setup at two different cambers.


The new planes from Brimfield. The dealer over-worked the razee jack a bit cleaning it up. I like a tool to show its history.


The soles all look good from a distance. However, I found in usage the sole of the jointer is slightly dished in front of the mouth. Why do these always looks like they were used to remove paint?


The irons all have plenty of metal left. I checked before I bought them!


The edge of the dirtier jack iron needs to be jointed first.


Jointing it on 80-grit paper on a granite plate, side-to-side with light pressure.


I cleaned up the back of the iron and the chip-breaker enough for rough setting.


I set the iron to project a little over 1/16"....


...then marked the sides.


Using a simple string compass to make 4" and 8" radius paper templates.


The 4" template lined up well with the marks, so I colored in that profile on the iron.

Cambering requires a lot of metal removal. For that I turned to the powered grinder. First I ground the radius profile flat on the end of iron, then I angled the work support and ground the bevel, dunking in water frequently. I stopped when there was a hair's breadth of the flat grind left and switched over to the sandpaper.

On the paper I used an alternating grind. First I swung my wrist back and forth to grind sideways until the grinder scratch pattern was gone, then switched to up and down the paper, again until the previous scratch pattern was gone, repeating this several times. Watching the scratch pattern is a good way to tell when you've adequately ground the whole surface in one direction.


Starting a sideways swing.


Ending the swing, keeping pressure on one side of the camber.


Up and down the paper. I focused on one segment of the camber at a time. This doesn't make a perfect curve, but who cares? This is for rough work, not fine carving.

I prepared the second jack iron the same way, except that I used the 8" radius template. Cambering an iron this heavily is time-consuming, but it only has to be done once, then can be maintained with subsequent sharpening. One fascinating aspect of these old irons once you get the bevel polished up is that you can just make out the two layers of metal where the steel cutter was welded to the softer iron.


The first jack setup with the 4" camber. This mouth looks a little dished out as well, but it's of no concern on a jack.


A test shaving: .080". That's a huge cut! Probably too much, in fact.


The razee jack setup with the 8" camber.


This one takes a much tamer .030" shaving.


Need to take out some aggression? Just spend a few minutes chewing a board down to nothing with a jack plane. Very satisfying.

Finally, time to use the full triumvirate of jack, jointer, and smoother to take an oak board down by 1/8", then finish up with a cabinet scraper. While the smoother left a nice surface, it still had a few ripples; the scraper took these down nicely.


Step 1: plane across the grain using the jack for heavy removal. This leaves uneven scallops across the width. This is less than a minute of work.


Step 2: plane diagonally, then with the grain using the jointer to straighten the stock, taking it down just to within final thickness. This brings the high spots of the scallops down and then starts taking full-length shavings, much like using alternating grind directions when sharpening the iron. Depending on how rough the jack left it, this takes from less than a minute to a couple minutes.


Step 3: plane with the grain using the smoother to smooth the surface, removing any scallops from the jointer. This takes fine gossamer shavings of neglible thickness. Less than a minute.


Step 4: use the cabinet scraper with the grain for final finished surface. This is less than a minute of work. Don't you dare get out the sandpaper!

In two to six minutes, depending on your control and the quality of your tool setup, you can take a board down by 1/8" and get a polished final surface. Need to take it down by 1/4"? That's just an extra 30-60 seconds with the jack.

After getting used to metal-bodied planes, these were a bit awkward at first because of their larger size and higher center of effort. But the reduced weight definitely helps. I also scribbled on the soles with a block of beeswax, which made a difference in smooth motion. I found that these planes rely more on a follow-through stroke, probably due to their reduced mass and consequent reduced momentum. Aim to end the stroke several inches past the end of the wood.


Checking the flatness of a piece of SYP. Nice and smooth.

The final bonus was this epiphanous moment, one of those things that makes learning to use hand tools so glorious: I finally got a cabinet scraper to take effortless shavings, not just dust.


Closeup of the fine oak shavings from the scraper instead of dust.

There were two keys to achieving this: a Ron Hock burnisher, and a video that Jacob Butler had pointed out. I had gotten the burnisher several years ago at a scraper class at Woodcraft. I already had another burnisher made by a manufacturer who shall remain nameless in shame, but my scraper just scored deep ruts in that piece of junk. Hock metallurgy proves superior again.

The class had taught essentially the same scraper sharpening technique as in the video, except for one critical element: take just one hand-held stroke with the burnisher. Previously I had been clamping up the scraper and applying heavy two-handed force in multiple passes. So I was over-turning the hook, ruining what the previous steps had accomplished. The method in the video is unbelievably quick, simple, and effective.

But this isn't my last word here. I was going to post a couple of videos showing the four steps above in real-time, but I need a little more practice, otherwise I'll do the tools a disservice. I've also done a little more work fine tuning them for better results, and tried some edge jointing while experimenting with love taps from the plane hammer. It's a bit like learning to plane all over again, but I'm progressing quickly.

(Continue to part 2)

Recommended Books and Videos
  Hand Tool Essentials: Refine Your Power Tool Projects with Hand Tool Techniques (Popular Woodworking)Coarse, Medium and Fine (DVD)

1 comment:

  1. Excellent post! Very informative. Looks like you're taking to the wooden planes just fine.

    ReplyDelete