One of the most important considerations in the design of the benchwork, as with most of what I am planning for the layout, was how easy it would be to parcel out tasks in a way that allowed all students to participate. The benchwork design for the blackboard wall consisted of three 8-foot long modules on legs clipped to the wall under the chalk rail, plus a special 6-foot long section for staging behind the door. That section is just a frame sitting on top of a bookshelf.

Each of the three 8-foot modules is made from three components: four legs, two L-girders, and an open frame panel on top. The staging section is just a frame. The legs and L-girders are assembled using 1/8” masonite gussets screwed to the wood with truss head screws.

Last year I had three classes of seventh grade math (plus two of eighth grade math). For a number of reasons I decided to focus the layout work on the seventh grade classes, so I was able to neatly assign each class responsibility for one of the components: one class did legs, another did L-girders and the third made the frames.

The class that built the legs had a relatively easy task: cut the 2x2 lumber to appropriate lengths and drill a hole in one end, then tap in T-nuts for carriage bolt feet.  Only two students in the class had ever used a hand saw before, but they were all very excited to try it. Perhaps you can remember your first attempt at using a hand saw – it probably wasn’t as easy as it appeared to be in the cartoons! But it was a beautiful process to watch. After a few minutes of struggle most of the kids were ready to learn, so I told them to take a break and we talked about how the saws work, looked at the teeth, and I explained how they do the cutting on the push stroke. I showed them how to clamp the workpiece to a table to hold it steady. I invited them to try again, but urged them to at least try slowing down and letting the weight of the saw do most of the work (for some of the students with raging testosterone storms going on that was clearly out of the question).

One of the students who was getting the hang of it by being gentle and patient remarked that going slowly and lightly was allowing her to follow the cut line more easily.

I didn’t have enough saws for everyone to cut at once, but most were ready for a break well before they made it through that 2x2. While the second shift was getting some experience I asked everyone to imagine we were in ancient Greece building a trireme, cutting every board and timber by hand.

Eventually we had 12 lengths of 2x2, with one end of each nice and square (the mill end!) I had everyone spend some time sanding their leg so we could handle them with less chance of splinters.

We’d already used up most of the class time but I had just long enough to take them to the drill press in the basement of the middle school building to give them their homework assignment. I took the top cover off of the drill press head to show them the three sets of stacked pulley wheels and how the belt could be configured to any combination of pulleys.

I told them that for homework they were to imagine a simpler two-pulley arrangement and determine the four possible drill spindle speeds that a 500 rpm motor could produce. I told them to assume the motor shaft had 7”, 5”, 3” and 1” diameter pulleys from bottom to top and the spindle shaft had the same sizes but in reverse.  

Middle school students have been taught all of the facts they need in order to figure this out, but many of them can’t remember those facts and those that can have probably never applied them to a problem like this. It’s just slightly out of reach for most of them.

The theme of my seventh grade math classes is dealing with uncertainty and ambiguity. What can you do when you get stuck? What resources can you draw on? What kind of questions should you write down for tomorrow’s class when the teacher asks “did anyone have any questions on the homework?”

These are universal skills. Math, model railroading, everything.

Jeff