When I was in college I spent a summer working in the fab shop where they built Rotaflex (PDF) oil-field pump units.  As the shop peon my primary job was to clean slag from the parts that had just been cut on the cutting table (not this exact model, but similar).  What this entailed was taking the parts (often while they were still hot) and using a big hammer to knock off the largest pieces, then using a grinder to clean them until smooth.

This wasn’t necessarily so bad in the grand scheme of things, or at least I didn’t mind it as much as when they had me “buff the beam” (*).  However, those Rotaflex pump units had a weight box inside that would hold between 8,000 and 15,000 pounds of steel plate in pieces.  These pieces were made by taking 2000-lb sheets and cutting them into rectangular pieces (about 12-inches x 16 inches).  Since these pieces were to be stacked in the box, the slag had to be removed from each piece by hammering and grinding.  Once cleaned, it was stacked on a pallet and then tied down using straps.  This whole operation was my domain.  On a good day I could clean and stack about 10,000 pounds.

Anyway, besides learning a few things about welding and fab shop operations, this experience left me with another lasting “gift.”  After a month or so working there I would wake up in the middle of the night with painful tingling in my hands.  It feels a lot like what happens when the blood comes back after circulation is cut off in a limb (like if your foot “falls asleep”).  It happens in both hands, but it’s worse in my right.  Often I will have trouble maintaining grip in that hand until I’ve used it for a while.

I hadn’t been bothered with this in a while, although it comes up every so often when I use certain hand tools and I aggravated it pretty badly this weekend.  I started out trying to trim an out-of-control bush so I could more easily get to my storage building.  However, I got tired of messing with it part way through and decided to just get rid of the damn thing.  This led to an extended bout with a shovel and an axe trying to get the stump out.  The ground underneath was hard as a rock since it was so dry and the stump was practically glued in.  Fortunately, the rain on Monday filled the hole and softened up the dirt underneath so that I managed to pull it out with a cable-puller (a.k.a “come along”) and some more judicious axe work.  But I’m still paying the price this morning, although it’s nowhere near as bad as it was on Monday morning.

I suppose I could see a doctor about this, but from what I’ve learned of RSI, it would likely require surgery and rehab to cure it, and even then I would likely still be susceptible to relapse.  Worse, someone I know who has had carpal tunnel surgery still has trouble with the grip in that hand, even after a supposed “full recovery” and rehab.  Given that my grip strength returns after a while, and I don’t want to risk weaking my stronger shooting hand, I suppose I’ll just keep dealing with it.

I suspect there’s probably a lesson in ergonomics somewhere in all this mess, though.  I know that repeated use of power tools (especially anything that vibrates) can cause permanent damage if you’re not careful.  I wonder if they’ve done anything about this since then?  I doubt it, though, since the job is generally handled by a temp or a college student working summers who won’t see the effects until a while after leaving the job.

* The frame of the pump unit is composed of two long steel I-beams, which were about 30 feet long and two or three feet wide.  When they start assembling a new unit, someone has to clean the entire beam with a grinder equipped with a wire-cup wheel to remove any rust, dust, or junk that has accumulated while the beam was in storage.  As the shop peon, it was my job to do this.  That wire cup wheel was a dangerous bit of equipment, and I treated it with a great deal of respect and never had an incident with it.  But still, I preferred not to have to mess with it.

The people at the shop called this operation “buffing the beam.”