Today we were fortunate again to meet with one of our closest friends on the way up from the park. We talked over the latest political situation (as we often do) and reinforced each other in the view that the lockdown may be coming two weeks too early and that apart from Leicester, there may well be other communities in the North and the Midlands with a socioeconomic profile not too dissimilar to that of Leicester where subsequent spikes of infection may still occur. After lunch, I was just getting psychologically prepared to give the lawns their 7-10 day mowing when the heavens opened – not for long, but just long enough to write off any thought of grass-cutting whilst the ground was damp. So I turned my mind to other things such as revising my Waitrose order that is due to arrive first thing on Friday morning. Halfway through the afternoon, I received a delivery from Amazon but it was not what I was expecting. Several days ago, I had espied on ebay a traditional hat-and-coat stand of the traditional bentwood variety that I had been looking out for some time and so I ordered it at what I thought was a reasonable price. I wasn’t sure what kind of packaging it would arrive in but what did arrive was a flat box with a self-assembly kit inside. This is not what I was expecting so I went back to the original advert and there was no mention of ant flat-pack or self-assembly. But I set to work with a vengeance following the pictorial instructions (no words of any description) It was one of these jobbies where the advice was to only screw things up halfway because there was a certain amount of jiggling about to get circular supports in place but all went well before I gave things a final tightening of the screws and then polishing of the whole before deploying it where I needed it in our bathroom. I have a variety of PosiDriv screwdrivers which I deploy on occasions like this as I invariably find that if one tool doesn’t work quite as well as intended then another one will. A final ‘tip’ was that I keep in a bathroom cabinet some especially ‘grippy’ gardening gloves – these I keep in pristine condition and use for things that require a good grip but are normally a bit problematic such as the rounded covers that are used when you fit on new shower hoses and the like. Anyway, this proved ideal for those vertical sections that needed a good twist to lock into position and I must say I am pleased with the results of my efforts.
Still on the subject of screwing together any pieces of timber for any construction works in the garden, I am keen to follow the advice given in my searches on the web to provide a ‘clearance’ hole in the top piece of timber that is being used and will eventually accommodate the smooth i.e. shank part of the screw. I had never thought much about why wood screws contain shanks but here is the explanation:
Having an unthreaded shank at the top allows the tip of a wood screw to pull the screw into the wood just as a regular screw would. The difference is that the shoulder portion of the screw will actually slide through the first layer of wood and pull it against the head. This causes compression from the head to the threads. When installing two pieces of wood together then the first will be pulled tightly against the second one. The threads can continue to pull forward as long as enough torque is applied. Coincidentally, this can also make the removal process much easier than trying to remove a fully threaded screw.
Second, when a fully threaded screw is being screwed into wood the screw threads cause friction. This friction results in the screw heating up. This causes two flaws in the material. As the metal heats up it will begin to expand. Once it expands inside of a hole that was drilled for a specific sized screw, the screw will seize in the hole. At the same time, the materials overall strength has now also been compromised due to the heat. Overheating leads to a screw breaking and snapping.
These two factors will highlight any flaws the screw may have and exploit them. This typically results in bending or snapping of the screw. So, how can a shank help? The shank allows for heat dispersion in a screw. As the threads begin creating heat, it moves up into the shank which will take longer to heat up and will not generate nearly the same amount of friction when it goes through the wood.
So another of life’s mysteries solved – something I am sure you always wanted to know!
The latest coronavirus news is that several other lockdowns are being considered. Further local lockdowns are “just days away”, Sky News understands. Sources in Public Health England (PHE) and the Department for Health told Sky News they are “working collaboratively”, focusing on the areas in England where coronavirus cases are rising.
© Mike Hart [2020]