April 24, 2021
Zen and the Art of Fiber Mill Maintenance
Learning how to care for our machines
By: Amanda Kievet
It started out as an innocent upkeep task. I came into the mill with the goal of pin drafting some roving orders and noticed that one of the oil reservoirs was a little low. As I was going to refill it, the little O-ring fell down into the machine. Deep breath — it’ll be ok, you just need to find it. A simple look into the crevices with my phone flashlight didn’t yield results so I went into our tool chest to get the big T-bar to loosen the bolts to open up the machine and get a better look.
At this point, I feel it’s helpful to explain how the pin drafter works: Multiple stacks of coiled roving are sitting at one end of the machine. We take the bundle tails — one from each stack — and feed them in on one side. The machine takes the bundle of fiber and passes it through a series of many comb-like bars called faller bars. There’s a set on the top and bottom with teeth pointing toward the incoming fiber in the middle. The bars move quickly along on a continuous loop, combing and drafting the fiber as they go. Out the other end comes much more even roving with parallel fibers.
Ok so back to the story. By this point, Peggy had noticed that all was not going according to plan so she dropped what she was working on to come over and help. “Why don’t we try taking out the faller bars?” Peggy asked. This was a task I’d been dreading but one we had to do a couple times a year anyway to clean them so I figured, why not? Then I noticed that a second O-ring — a different size one from the inside of the machine was missing. Peggy decided to run to the hardware store to look for replacements to both of them while I extracted the bars.
By the time she got back from searching at multiple hardware stores with exact matches for the inside O-ring (along with dish soap and some brushes to wash the bars), I had all of them out and in the sink. With 16 grease points, the inside of the pin drafter is quite a greasy place. I felt my way through every mucky dark corner of the machine and came up with two completely covered-with-grease rags but no luck finding our missing O-rings. I decided it wasn’t going to happen.
By this point, it was afternoon. Peggy headed out to try auto repair stores for a match to the top O-ring, and I got to washing the bars. Turns out there are a lot of them — 74 to be exact. Peggy came back an hour or so later as I was in the process of drying them. She had found a solution to the top ring! A man at one of the shops helped cut the inside out of a rubber component which perfectly fit and sealed the hole. Success!
As I was reinstalling the bars, I realized that I had forgotten to take a top-down photo of the top set of bars, so I wasn’t 100% sure which direction they should go back. I took a guess. I jogged the machine to advance those bars so I could put in the next batch and something got stuck. A flush of panic came over me. I quickly turned off the machine and assessed the situation as I felt myself go sick to my stomach. Peggy came over and I explained what the issue was. I was afraid she would panic with me, but instead she calmly suggested we open it up to see if we could get the stuck bar out. As I went to push it out, I felt the top tracks rotate and the pit in my stomach grew even deeper. In my mind I heard the voice of Michael Hampton, “the one thing you never want to do is mess up the timing.” I knew I had done just that.
I told Peggy my suspicions while going into our toolbox to get the timing tools, which Michael explained but then added, “you should never have to use these.” At least we had them. I got the stuck bar out, and with tears in my eyes we took a second to breath and figure out what to do. We read and re-read the instructions. First, take one gauge and turn the machine manually until the S-cam touches it. This seemed simple enough from the photos in the manual, until we realized that we were looking at a roller completely blocking us from accessing said S-cam. Time to call Michael and see if he had any words of wisdom.
As expected, he said he never had to do this, but offered that his friend at a different fiber mill did, and that he claimed it could be done visually by referencing the photos. While he was on the phone I verified which direction the top bars should be replaced. To my surprise, I actually had them going in the correct direction. I realized something probably got turned while I was removing the bars in the first place.
We slowly and carefully got the bottom S-cams into the correct position, and even managed to sneak in the gauge past the roller to double check. Then we turned the top cams and used their gauges to get the position right. We carefully closed the machine, ensuring that the gears came together correctly. Then we manually rotated the machine and as we put back all of the top bars. This was tough going which led to sore arms by the end of it. Finally the moment of truth: we flipped the switch and jogged the machine. “It should sound like it normally does,” was Michael’s suggestion on how we’ll know if we got it right.
It did, and we were hugely relieved. And not only that, we felt like we had overcome a nightmare of an obstacle. It’s not a stretch to say I had nightmares leading up to opening this mill about this exact scenario — one of a handful of what-ifs that kept me up at night after our training sessions. Well, we managed to figure it out, learning a lot more about the clever way this beautiful greasy machine works, and about the value of having a business partner who can talk you off the cliff.
As a final test we sent through some test fiber and it came out beautifully pin drafted. We didn’t get much done that day, but we ended up with a valuable lesson. And some backup O-rings.