Tuesday, June 3, 2014
Greetings from Weardale.
Welcome to the little corner of purgatory where old equipment, which has outlived its usefulness in mainstream industry and somehow managed to avoid the scrap heap lingers on in the hands of amateurs. Fifteen years ago I was just beginning to become aware of just how blissfully ignorant most of us were about what we were getting into with this project. To this day I am still reminded of that fact, but so far it hasn’t stopped us. Yet.
For those of you unaware of such bits of mining history trivia, the Eimco 12B pneumatic shovel, invented in the 1930s revolutionized the mining industry, much as the somewhat earlier invention of pneumatic rock drills did. Prior to the Eimco, when someone wanted a tunnel, men with shovels moved the rock after blasting. A life of this kind of work was generally a short one. By automating the shoveling and removing of rock and ore, what was formerly a week’s worth of back-breaking work could now be done by a small team in a day. This is a fine example of the “progress” that the appropriate application of technology can bring.
But as “progress” continues, today’s progress consigns yesterday’s to history, and that’s pretty much what an Eimco 12B now is – an historical artifact. The sort of small-scale mining for which they are designed is rarely done anymore, at least in the “developed world” – except by a few anachronisms like us. In practical terms, what this means to us is that when something eventually breaks, there are no service manuals or exploded diagrams of the thing available on the internet, and most of the folks who once maintained these things in the local mines are long gone, and the specialized tools required for the work are now scarce.
Our local miner Dave had 25 years experience in the local mines before joining us, but he’s a miner, not a fitter, and in former times left the fixing of these things largely to others. Fortunately, he still knows how to get in contact with a few of these “others” and can at least get some advice. Still, there’s nothing like experience, and that’s what we’re now acquiring.
A week ago Dave noticed that there was a problem with the drive mechanism in our Eimco. After asking a few folks who had worked with these things, the general consensus was that a bearing had collapsed inside the gearbox. To get the access plate to the gearbox off, one must first remove the wheels on the left side of the thing. The required tool is called a wheel puller, and to remove 14-inch wheels that have likely been in place for 50 years required a big one. We tried to improvise one, but no success. We searched for one to rent but no success. Finally, after almost a week, Dave found someone here that still had one of these things. He brought it up to the mine on Saturday and within 45 minutes the wheels were off. I am certainly glad we found this guy because the puller frame we had thought of building ourselves wouldn’t have been up to the job!
Yesterday at the mine we were finally able to remove the plate and have a look inside. Sure enough, there was a collapsed bearing and little steel balls were rolling around in the gearbox oil. All-in-all, there are 10 bearings in the gearbox, and most are showing various degrees of wear. No surprise considering all the years the thing has been in service. I don’t think you could buy a piece of kit like this today and expect 50 years of good use out of it! Since we now have it opened up and its guts spread about, it is probably a good idea to replace them all.
So how do we do this? Well, there’s a bearing supply shop in Bishop Auckland where we can likely get new ones. How do we get the old ones out and the new ones in? Well, on page 283 of the Machine Mart catalog there’s something called a “bearing puller” so maybe that’s what we need. I’ve also found that in a place like this, asking around the pub about things can turn up lots of useful advice. Yesterday evening I found out about something called “freeze-spray,” which is basically a can of liquid carbon dioxide that when strayed on something makes it very cold very quickly. Plumbers use it for fitting metal pipes because when cooled, metals tend to shrink nicely. Would probably work nicely on bearings as well. If we can get our hands on the stuff, I guess we’ll find out.
At for the weather, it has been sunny, then rainy, then sunny again over the past few days. The rainy part invariably happens when we’re all huddled about the Eimco outside on the mine landing, as seen in today’s photo.
Forward in all directions.
Jesse, Ian, Cal & Kerith
Just singing in the rain - again!