This is another entry from John who is referring to his previous post Titled “First Class Practice”
As you recall I am making the base of the Trestle Table and am in the process of making notches in two members so when they are glued together I will have a mortise. After sawing into the waste a number of times, I removed it by hitting it with a hammer. A good Maydole hammer no doubt, but any hammer will do. Here is what the joint looked like. Not only doesn’t this look nice but I don’t think I am going to get a good glue joint.
So I took out my Stanley vintage router plane and went to work. Here is the result!
See how much tearout there is on the near-right side? And this was one of the best examples. I was planing directly across the grain and boy did I make a mess. I learned that I could avoid this by canting the plane and paying close attention to the wood that made contact with the iron. It was kind of like saddling an Elm chair seat with an Inshave. If I continued to make angle adjustments I could get a good result. I also used the two top sides of the work as a reference for the sole of the router plane.
I had to adjust the depth a bit deeper than intended but this is the final result. You can still see where big area of tearout was, but this will make a good glue joint.
For explanation purposes here is how I used the sole of the router plane on the work.
Now that shop class is as common in high schools as poodle skirts, lots of woodworkers worry about passing on our enthusiasm for the craft to the next generation. In my house, I’ve started treating my kids more like apprentices, and it seems to be working.
They help clean the shop. They assist me on projects at assembly time. They can work on their own projects on the side when I don’t need them. And – here’s the odd part – I pay them (a pittance) for their help and swear them to secrecy on the “arts and mysteries” of the craft.
This weekend has been a perfect example. I assembled a large run of shelving that I plan to install in the recipient’s home this week. There was a lot of tedious gluing, clamping and clean-up work involved, so I hired 7-year-old Katy to help.
First, I showed her the “secret” to making the lacquer finish perfectly smooth to the touch – a folded up brown paper bag. We rubbed all the surfaces vigorously, which knocked down any surface imperfections without cutting through the film finish. Katy did the shelves; I did the uprights.
“Cool,” she said. “It works!”
As we were bagging the lacquer, both of us noticed that there were some small dings and scratches in the color. This is was the result of the parts getting moved around more than I like. So I swore Katy to secrecy again and introduced her to the mystery of stain pens. In this case, the best match wasn’t one of my stain pens (which I keep hidden away), it was a black Sharpie marker.
In fact, Katy became incredulous when I took her picture at work with the marker.
“What if someone sees the picture and figures out our secret?” she asked. “Then they’ll know!”
Then we glued up the shelves. I applied the glue. Katy added the Dominos. We both applied the clamps and cleaned the glue squeeze-out. Assembly can be stressful for me, but Katy’s amazement at how the project came together kept my anxiety in check.
We did four major glue-ups this weekend, and by the fourth one, Katy dove into the work like she had been doing it all her life. I wonder if learning woodworking is like learning a foreign language – it might be easier when you are young.
As I added the kicks to the cabinet, Katy worked at the bench at her own project – she’s transforming my discarded shop jigs for this shelving project into a wooden alligator.
Then I paid her (about $1 an hour for the shop time) and I asked her if she’d come along on the installation next week. With hesitation, she said: “Yes! Hurray!”
Next step: Getting the apprentices to fetch the small beer for the master.
Somehow, during the course of about five years, I became a math dolt. When I left high school, my SAT scores for math were near perfect – far higher than my verbal score.
But after four years of studying intransitive verbs, subjunctive mood and zeugmas, my math skills withered to the point where – no lie – I couldn’t figure out the formula for the perimeter of a pentagon during a college class we all called “Math for Trees.” My wife still mocks me for this.
So I’ve always been at a loss to explain to readers the different curve required on the blade of a bevel-up smoothing plane vs. the curve required for a bevel-down smoothing plane.
The brain-dolt answer was always: The bevel-up planes require more curve to take the same shaving as a bevel-down smoothing plane. But that was about as good as my explanation got.
A couple weekends ago, David Powell explained the math to me during a presentation at the Northeastern Woodworkers Association’s Woodworkers Showcase. I retained the explanation and formula only until the next morning. (Honest: I had only one beer that night. Perhaps is was the lamb korma.)
In any case, I took notes during the presentation that are useful for the shop. If anyone wants the formulas, you can probably ask Powell himself. Powell was the founder of Diamond Machining Technology (DMT) and is now the maker of the Odate Crowning Plates. The plates are diamond stones with a curve built into them so you don’t have to use finger pressure to create the curve on the blade.
Powell’s numbers assume that the iron has a curve created by one of his diamond crowning plates. The plates are dished to mimic a 37-1/2’-radius circle. Powell’s numbers also assume you are using 90 percent of the iron of the tool during the cut.
So here goes: A bevel-down No. 4 handplane with a 2”-wide iron that is bedded at 45° will take a .002”-thick shaving if it has an iron that is sharpened with the Odate crowning plate.
Now let’s take a bevel-up low-angle block plane with its 1-3/8”-wide iron bedded at 12° and the iron sharpened at 25° (the angle of attack is therefore 37°). Powell says this plane will take a .0005”-thick shaving if you use 90 percent of the iron in the cut.
How about the very popular bevel-up jack plane? It has a 2-1/8”-wide iron and also is bedded bevel-up at 12°. If you have a 25° bevel sharpened on the iron, it will take a .0008”-thick cut. If you have a 38° bevel sharpened on the iron, the plane will take a .0006”-thick cut. And if you have a 50° bevel sharpened on the iron, the plane will take a .0004”-thick cut.
While these numbers don’t tell you how much extra pressure to put at the corners of your iron to make that extra curve, there is a good piece of data here. And here it is: Use the same curve for all your smoothing planes.
A plane bedded at 45° is best suited for mild woods. So its .002”-thick shaving is about right.
Planes bedded at higher angles are used for curly, exotic or just grumpy woods. So the best strategy is to take a thinner shaving (thinner shavings help reduce tear-out in my experience). So a shaving thinner than .001” is an excellent choice. And that’s exactly what you’ll get with a high pitch.
So all that math boiled down to this: Don’t bother with the math. Just stick with the same curve for bevel-up or bevel-down and you’ll be OK.
Editor’s note: The following blog entry was penned by John Hoffman, my business partner here at Lost Art Press. He wrote this after assisting me during my sawing class up in Sterling Heights, Mich.
— Christopher Schwarz
I am in the process of sawing out large notches for the Trestle Table from Woodworking Magazine. I have been experimenting making first-class saw cuts. I have used the chisel with the bevel toward the waste and away from the waste as suggested by Chris. The key for me is to not tap the chisel to hard. I am using Southern Yellow Pine, (an exotic wood to Canadians) so it is not hard, however, I have been able to cross the baseline with either bevel approach if I hit the chisel too hard. The other experiment I have been doing is to see how much of a notch I need to make with the chisel for the saw to ride in.
In this pic you can see a deeper notch and a shallow notch. I have tried to keep the shallow notch deep enough to cover the saw set. Noctice the somewhat crocked lines made from my dull marking knife.
The next pic is the result. Again the lines seemed to work out well and it seems that the smaller notch worked fine. Notice the notch in each corner to guide the saw. It was a bit tricky because the work is only 1-1/4″ inches thick which put the sawing close to the bench top.
Yes I did run the toe of the saw into the top of the bench, but only once. Really! I then continued to practice sawing to the line to waste out the rest of the material. This is the result.
If you look closely some of the saw cuts are definitely better than others. I tend to wander off line at the far end of the cut. I have been focusing on watching the reflection of the work on the saw plate to help me stay true. Another trick from Chris, who told me the best thing to do is keep on sawing.
Aside from eBay descriptions, photographs might be the biggest fibbers in the world of tools.
I’ve just finished judging a toolmaking contest sponsored by WoodCentral and Lee Valley Tools. During two days, I and two other judges examined, used and quarreled about more than 70 amateur-made tools. Our task was to award three prizes: the best-looking tool, the one that displayed the highest craftsmanship and the tool that worked the best.
As the entries came in, Ellis Wallentine of Wood Central posted pictures of the tools that were snapped by the makers (you can see those pictures here). I checked back every week or so to take a look at the entries and get a head start on judging.
Judging this contest, I thought, was going to be a cakewalk. We’d wrap it up in a couple hours and hit the Irish pub near the Lee Valley headquarters and spend the afternoon yucking it up.
It didn’t work out that way. In fact, the Lee Valley folks had to gently push us out the door after the first day of judging.
Here’s what happened: Photos are sometimes deceiving. Though some tools looked as good as they worked, other tools that looked like a million bucks in photos couldn’t cut a soggy toothpick in half. Tools that looked like they came over on the Mary Rose were so sweet they would almost do the job themselves when you went for a bathroom break.
And then there were the “ugly” tools. The tools that looked like they were made in a style that you had to wear either a black beret or Big Smith overalls (and no shirt) to truly appreciate. These tools managed to bore their way into your heart like a tapeworm in an Arkansas rice paddy.
So we argued about the tools. We almost abandoned any hope of awarding a prize for aesthetics. We were just too far apart. The craftsmanship award, however, was a little easier. There were lots of well-made tools, but some required more varied skills to make than others.
And function? That was the easy prize. When the steel hit the wood, it was quick to see which tools cut the mustard and which should be used only for resawing the mustard. In the end, using these tools radically changed my view of them. I didn’t care if the photos looked like junk or they had been professionally shot. When I looked at the pictures I saw only a tool that worked or didn’t work. As a result of all this, I was really pleased that we judged this contest in person and not via the photos. I think we got it right.
I cannot say yet which tools I personally liked or which tools I didn’t, but I’m including a few photos I snapped during the judging to break up the awful grey page generated by my typing prowess. When you take a gander, just make sure that you remember that pixels can be a crock of poo.
