A year or so ago Natalie and I went into Homebase for a few washers or something and left having bought two childrens loft beds with study areas underneath. Just the thing when you have a couple of pre-teens with too many possessions. They were delivered a day or so later and we, having evicted the previous beds, got to work. At fist it all went pretty well, although we used our own tools rather than the silly little allen keys in the kit. We assembled one together with no more hassle than having occasionally to drift a couple of misaligned holes together, so Natalie decided she could do most of the second one all by herself. After a certain amount of time she called for help. A screw wouldnt go in. It was perfectly well aligned but just wouldnt bite. I tried, full of confidence in my ability to succeed where she had failed but I couldnt get the thing in either. I examined the offending screw, a ¼ inch or 6mm machine screw with a fairly coarse thread. Its thread was undamaged. I looked at the hole in the tubular steel strut it was supposed to go into; instead of being threaded, it was plain.The answer was of course to thread the hole. Luckily I am the sort of chap who has thread gauges, taps and dies around the garage, so I wasnt anticipating any problems. A quick turn or two with a 6mm metric tap and the job would be done. Or so I thought. Luckily I had the foresight to check the thread before getting going, and I discovered that whatever it was it certainly wasnt metric but some strange Yankee thread; ¼ UNC or something like that. Without going too far into things it turns out I did not have a tap to suit. What to do?
A year or so before Natalie had bought me a very erudite book on clock repair; not the how to clean it but leave the rest to the professionals type but a how to do things no professional would waste time on book. Among other tricks it suggested a way of making your own taps and dies for watch and clockmakers screws. Could I try the same trick? It looked possible although I would be working at a much larger scale.
I took a spare screw and shoved it in the 3 jaw chuck of my lathe (a Myford Super ML7 for any machine tool freaks out there!) and turned a slight taper onto the end of the thread. I then filed two cuts into opposite sides of the thread, reaching up about 4 thread widths. I widened the cut and backed off a little to give a cutting edge. I then hit the challenge; hardening the thing. I had no idea of the quality of the steel I was using; the clock screws the method was intended for are invariably high carbon steel and harden easily. I frequently make D-bits, counterbores and such things, but I always use silver steel, which I know exactly how to harden and temper. This screw was some nameless form of stainless with unknown hardening characteristics. I decided to be unsubtle. I heated it to cherry red in a blow torch and plunged it unto a container of filthy sump oil on the grounds it could probably do with some extra carbon in it ..
The resulting object was not a thing of beauty and I had no idea how long it would hold its edge. Luckily it only had to cut one or two turns. It managed that with no problems, and we finished the bed in time for our daughters bed time.
A typical piece of flat pack furniture, really, assembly instructions included, requires only simple hand tools plus;
Screw thread gauges,
Needle files,
Engineers lathe
Blow torch
A simple brazing hearth
Sump oil.
Knowledge of model engineering, gunsmithing or similar would help.
Nationwide spy system to track millions of car journeys a day - the Times
Britain will be first country to monitor every car journey
- the Independent
John K, a Samizdata commenter, says:
My sister's number plate was stolen the other day. I think the rise of the congestion charge and gatso infestation has led to a rash of these thefts. If this insane plan goes ahead there will be many more such thefts. Criminals don't give a toss a bout the law. That's why they're criminals, and that's why this is a piece of authoritarian population control disguised as a crime control measure.John K's final line is a slight exaggeration. However his point that criminals, because of their criminality, have less to fear from this sort of measure than law abiding people do is an important one and provides the title of this post.Only the innocent have anything to fear.
We may end up being grateful to some criminals. I've posted before this post from a Dutch blog on how they deal with such things. I was going to pussyfoot around with one of those "merely academic interest" disclaimers, but I've got a rotten cough and a temperature and I couldn't be bothered. Go Dutch.
