Fasteners #1: Introduction and cleaning oily fasteners

Update 11/9/09. Alas yes, I have gotten a bunch of work done on my projects but haven’t found time to write a proper post about it.  I started driving the GTV to work and tonight the battery gave up on my way home.  A friend picked me up, and we got it going.  I borrowed a new battery from another friend until I can figure out if it’s alternator or battery related.  On the bright side I had just spent a half an hour getting the heater core hooked up and heater fan working so I wont freeze on the way to work at 630 am tomorrow.

Enjoy the below post which maybe 3 people read the first time around.

Originally posted May 9th, 2008. Years ago when someone would ask me how I managed to get a project together, and wasn’t I daunted by all the parts that they saw laying about I would reply casually, ‘It’s all just nuts and bolts with a few special parts thrown in’. Little did I know how true this ingenuous response was. I didn’t however grasp the complexity and importance of those nuts and bolts.

I was thinking about this yesterday as I was working on the rear axle ‘casing and covers’ to quote the parts book. Besides a few big obvious parts I ended up with a pile of nuts bolts and washers. I usually bag and tag the fasteners after cleaning, or loosely assemble the parts if possible, but sometimes I get interrupted and 3 weeks later I find myself faced with a crusty pile of unfamiliar nuts and washers to try and identify. I looked at the parts bookto see how much information it had on these and it has a simple but useful nomenclature: what it is, what size it is, what it’s for. I guess if I get in any trouble I can reference the parts book.

Axle housing nut getting cleaned up.

Fasteners are much more complicated than they appear to the novice. Getting past the basics like Metric versus Inch and obvious material differences like plastic, steel and brass one encounters a subject of great complexity. Everything seems to have another level of differentiation as you dig deeper. A good example of this can be seen when you look up a part at McMaster-Carr. Just for fun go to their website and try and find the nut above, it’s an M8 x 1MM, probably grade 8.

Alfa Romeo had been in the business of building cars for about 50 years by the time one of their engineers, probably Busso’s assistant, decided the flange on this rear axle housing for the new Giulietta range needed an array of 8 M8 x 1.25 x 8 x 1 x 32mm studs and locking plates with corners that could be bent up to secure the 8 M8 x 1mm nuts. This engineer was paid to do some moderately complicated math that takes into account the surface area and material of the mating surfaces, all possible loading conditions, environmental concerns, life expectancy and most importantly machining and material costs. Nothing is left to chance, not even the compromises.

I have seen a lot of cars at car shows and whether restored, freshened up or original, many of them seem to have had some of their original fasteners replaced. It’s ok to replace damaged fasteners or those that are meant to be single use due to aggressivetorque specifications but to go to your local hardware store and replace everything with overly bluish Cad plated or gold-ish Zinc plated cheap fasteners ruins the subtlety of the machine and is just plain amateurish.

The point of the last three paragraphs: if you have the original fasteners and they are safe to reuse and usable, then by all means use them.

The rear axle was covered by a caked on mixture of oil and road grime. I used a dull pocket knife to cut big chunks of crud off the assembly, like peeling a carrot, to first find the fasteners, then make it so my socket would fit over them. Close to 50 years entombed in the oily mix preserved them nicely and they come right off without hang up except 1 stud on the differential ‘oil pan’ that appears to have encountered a rock at some point in its life. Some people would have you clean an assembly as a unit before taking it apart, but I don’t have any easy way to deal with a whole rear-end so I chose to take it apart and deal with it a piece at a time.

I throw the fasteners in a bowl of Kerosene type solvent to soak while I go find gloves, safety glasses, the brushes I will need, and a paper towel to put them on when they are clean. Each fastener gets it’s head or outside brushed clean then the threads either chased by a gun barrel cleaning brush if its a nut or brushed with a small wire brush if it’s a screw or bolt, rinsed, then set aside to dry. Note, just about anything you use to clean oily fasteners is going to be toxic/flammable/carcinogenic/illegal to dump etc so use your head, follow directions and be safe, using gloves and safety glasses.

I got this barrel brush a few years ago at a gun store in Sacramento. It has cleaned a LOT of nuts!

The locking plates and a few nuts sit on a towel to dry.

The end of this stud encountered a rock or curb at some point and needed some special attention.

Among the group of fasteners I cleaned was the stud seen above. It came out of the aluminum differential housing rather than allowing the nut to thread off. To remove the nut I first filed away as much of the damaged part of the stud that wouldn’t let the nut past as possible. Next I ‘double-nutted’ the other end of the stud, threading two nuts onto it then tightening them against each other. The double-nutted end is tightened in a vise and the nut threaded off. The tighter the nut you are trying to remove is, the tighter the double nut has to be. In this case it didn’t require much force to remove the problematic nut. The final step is a quick chase of the damaged threads either using a thread file or a die lubricated with a little light oil. A die will remove material from healthy threads so you should only cut the minimum possible to fix the damaged threads. A high quality set of Taps and Dies is an inexpensive, wonderful tool to have.

Only a couple hundred fasteners left to clean! Future discussions of fasteners will include dealing with rusty fasteners, washer types and uses, liquid thread lockers, plating, pins and other topics as required.

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2 thoughts on “Fasteners #1: Introduction and cleaning oily fasteners

  1. I claim 4th spot.

    Reading your posts relaxes me in the evenings; thanks Matt. Especially the above post, I felt like I was re-reading the book “Zen and the Art of Motorcycle Maintenance” – it was my bible for a while.

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