While searching for images of flanging machines to use on my blog I noticed something strange. None of the flanging machines had machining arms. Since the flanging machines at Brighton have cutting arms mounted on them, I assumed all flanging machines have cutting arms. Apparently not. At Brighton the machining, or cutting, arm is mounted on the side opposite from the controls. Here is a photo of me on the flanging machine I operate most of the time.
I am on the flanging control side forming a carbon steel head. Once it is in size, I will come around to the other side to machine, or trim, the edge. The cutting arm is painted cream colored, while the rest of the flanging machine is blue. The cutting arm is on a horizontal screw that you crank by hand to whatever angle you want. The idea is to keep it pointed to the center of the head, so you adjust it according to whatever size head you working on. An electric motor runs the entire arm up and down on a vertical screw. On the smaller arms, like what is mounted on the flanging machine I run, an air cylinder brings a roll up against the head, allowing the cutting tool to follow the surface it is cutting. On the larger machining arms a hydraulic motor moves a roll up against the outside of the head, while another roll, a pinch roll, comes down to press against the inside of the head. And instead of moving up and down a screw turned by an electric motor like on the smaller arms, the larger arms remain stationary, while the part of the arm with the cutting tool and pair of rolls is moved up and down manually on a chain, then locked into place. In all the arms an electric toggle switch moves the cutting tool up and down and in and out. We use tool holders, such as these:
fitted with carbide inserts, such as these (we use the square and triangle types):
to machine the tank ends.
It wasn’t always so. These machining arms appeared in the early 80’s. When I first started, in 1973, the machining arms were cruder. There were no electric or hydraulic or air controls. Everything worked manually, on screws. The operator adjusted the angle by hand, then bolted it down. There were two large screws, one for up and down movement and the other for in and out, and you cranked on a wheel manually while you machined. A very physical process.
Also, we didn’t use inserts. They came along with the new machining arms. We used carbide tools such as these:
These were long rectangular pieces of steel with carbide tips affixed to the ends. As you can see, the carbide tips are all different shapes, for different cutting applications. They didn’t come this way. We ground the tips on a floor pedestal grinder to get the different cutting surfaces you see. Then we had to grind on them to keep the cutting edges sharp. Which was very frustrating. You spend time grinding a cutting tool the way you needed it to be, then while you were machining it chips. Which sends you back to the pedestal grinder to repair it. Or worse, it breaks. Which sends you back to the pedestal grinder to start over with a new cutting tool. Many many hours I’ve spent grinding cutting tools. As you can imagine, once you fashioned a good cutting tool you took care of it, because it would take a long time to replace it.
Grinding cutting tools is a lost art. Thank God. I don’t know how many times I’ve burned my fingers holding cutting tools that were getting hot from the grinding. Or how many times I’ve trimmed my fingernails on the grinding wheel. And the rapidly-spinning grinding wheels can explode, but that never happened to me. If you look at the inserts, you’ll see the square ones have 4 cutting surfaces on a side, for a total of 8, while the triangles have 3 cutting surfaces on a side, for a total of 6. So when a cutting surface gets dull or chipped, you merely rotate the insert to the next cutting surface. Or if the insert shatters, you merely replace it. No more time-consuming grinding.
Or leaning on long wooden four by fours. We did this to keep the cutting tool tight against the surface it was cutting. If we didn’t, we’d get chatter (a rough notched surface instead of a smooth cut), or the tool would chip or break. The old machining arms were worn-out and allowed a lot of vibration. So to machine a head you would grind the tool you needed, then position the cutting arm, then crank the screws by hand to move the arm up or down and in or out, and you had to crank very hard to get the arm tight enough against the spinning head. Then you threw on your 4×4 and leaned down on it with all your weight in order to get a good cut. Of course, the vibrations from the maching arm passed through the wood into your bones, jarring you for hours. A very tiring process.
Now all we have to do is line the machining arm up, change the inserts, and manipulate switches. Not only is this much easier, but it is much faster. Amazing how that old adage ‘work smarter, not harder’ always proves out.