I’m sure by now you know the routine I’ve gotten into. A post about the work order, followed by a post about a co-worker. So it’s time to get back to the work order. The next item of interest is this:
This line on the work order informs me what kind of machined edge the head gets. A beveled edge gets cut at a certain angle. This particular head gets a thirty-seven and a half degree outside bevel. That and a thirty degree are our most common bevels, although they can be any degree the customer requests. The land is the part of the edge left flat. One-sixteenth inch is the most common land, although we do get a lot of one-eighth inch and zero, or no land, cuts. But like bevels, the land can be any dimension the customer wants. As you would imagine, we can cut the bevel to the outside, like this one, or inside, whichever the customer wants.
We also cut tapers. They are cut to a certain thickness and degree. A four-to-one taper means that for every fraction of thickness cut in, it is cut four times that down. Say a customer asked for a four-to-one taper cut to a quarter inch on a three-eighths thick head. I would cut the taper in one eighth inch, and make its length one-half inch. To do this the taper tool I cut with has to be angled to a certain degree. A four-to-one taper is cut at twelve to fourteen degrees. A three-to-one taper is cut at sixteen to eighteen degrees. A five-to-one taper is cut at ten to eight degrees. These tapers can get quite long, depending on how deep the cut is and on how thick the head. A five-to-one taper cut a quarter-inch into a half-inch head will be an inch and a quarter long. Of course, tapers can go on the outside or inside.
Bevels and tapers can be combined, with both on one side, or on opposite sides. What can be tricky is a double bevel. The customer usually wants them to be equal in width, with or without a land in the middle. Or the customer might want one bevel to be wider than the other. Even trickier. And then there is the double bevel, with a land between, and a taper on one side.
The most difficult to cut are bore-ups. These cuts are perfectly straight for a certain length, with a taper at the bottom to blend the bottom of the bore-up into the head. I have to grind a special carbide tool for that. Even then it’s very tricky. Say a half-inch head gets an inch-long inside bore-up into three-eighths inch. I have to make a perfectly flat one-inch long cut at the edge in one-eighth inch, then blend the bottom of the bore-up into the head with a taper tool that doesn’t cut into the bottom of the bore-up. We don’t get many bore-ups, thankfully.
The simplest machine job is a square cut. This merely cuts the edge flat. And we do get orders calling for an untrimmed edge, which means no machining at all. But those are rare.
These machining jobs might not seem too difficult to skilled machinists. But remember, I do these cuts on pieces up to twelve feet in diameter, and even larger. These aren’t small components we work on.
Machining has gotten much easier with the new machining arms. They are so smooth. The old arms were loose and worn out. Once we got the tool to cut into the metal, we would place a long four-by-four onto the arm and bear down with all our weight. We did this to keep out the chatter. When the tool bounces over the edge instead of biting into it, you get ridges in your cut which, if you couldn’t smooth them out, you would have to grind out. Even with the four by four you could still get chatter, which meant you were being seriously shaken as you hung onto the four-by-four. And some of these machine jobs could take a long time. I would go home exhausted and aching from hanging onto a badly-vibrating four by four for hours. On the old blue valley flangers we used to turn the machine off and on, jog the machine, in order to get a better cut. I’m sure that wasn’t good for the machines. But the change in speeds helped smooth the chatter out.
This one flanging machine had the worst arm in the shop. Everybody got chatter on it. So once they stopped hacking at the edge, they would grind the cut smooth. But if the head was very big, or very thick, or if the chatter was especially bad, you could be grinding for a long time. I was determined not to grind. So I fashioned my cutting tool to do a very shallow cut, barely graze the edge to peel off an extremely thin sliver of metal. But in doing that the squealing was unbearable. I merely shoved my ear plugs in deeper and went for it. People would cuss at me, throw things at me, for making so much noise. People in the office complained. This machine was in the center of the shop and the office was in the front, and they complained about the racket they could hear through the walls. Motorists on Mosteller Road would turn up the volume of their radios as they drove past. Truck drivers a mile away on Interstate 75 would pull over, thinking their engines were making a horrible sound. But I would get a smooth cut that didn’t need grinding. Nobody else could do that on that machine.
The old arm on that machine has since been replaced. But I still haven’t shaken that reputation. On the flanging machine I run most of the time now you can’t even hear me machine, it’s like a whisper. But people still complain about me being noisy. They remember what I was like on that other flanging machine, with the old machining arm. Once you get a reputation it is sure hard to lose it.
And that brings me to an old joke in the shop – “This place isn’t as noisy as it used to be.” Actually, it isn’t, with the new machining arms the noise level has dropped considerably. But that’s not the point of the joke. The point is our hearing has deteriorated so much over the years we don’t hear the noise as much as we used to. It only seems not as noisy to us because we can’t hear as well. Funny joke.