I’ve responded to the first 31 “Book of Plates” emails that landed in my inbox yesterday morning at 10 a.m., and I included tracking emails on almost all the packages (which are now at the post office). So I’m afraid if you haven’t heard anything from me, yours was not among the first.
This is one of the most common methods of joining components. It is interesting that while British use the name ‘turnscrew,’ the American term is ‘screwdriver.’ This is significant in that a screw properly arranged should not need to be driven, which implies hard work, but merely turned.
The screw has the following parts (Fig 75): head, shank, core and thread, and provision must be made for each of these in drilling the hole, since the screw, unlike the drill, cannot remove any wood. A standard screwed job (Fig 76) is one piece screwed directly to another and Fig 77 shows a section through the joint. The top piece needs a clearance hole made with a twist drill, in which the shank is free to turn. If this is too small much more effort will be required and the screw slot may be damaged, or the work may split if the hole is near the edge. The top piece may require countersinking. The correct tool for this is the snailhead countersink, but as an alternative the rosehead bit or drill may be used (Fig 78); however this is inferior, being designed primarily for metal. A larger twist drill may be used, and this is most successful when used in a drilling machine with a depth stop.
The pieces can now be held in position with the screw dropped in place. A light tap on the screw will leave a dimple on the lower piece on which the next hole can be drilled. This is the pilot hole and its diameter is that of the screw core. The principle is that the drill makes room for the screw core and the thread bites into the sides of the hole, giving the greatest strength with the minimum effort.
The screwdriver end should be well maintained and the blade must fit the slot. If allowed to become rounded it will slip out. Too large a blade will damage the wood, too small a blade will probably slip from the slot. Handles are made in proportion to blade size in order to exert the right pressure. Long, thin electrical screwdrivers should be used with particular care to avoid stripping the thread in the wood.
Fig 80 shows alternative screw heads. The round head is commonly used to secure fittings. If these are very thin a shallow clearance hole will be required for the shank before drilling the pilot hole. The raised head is sometimes used on metal fittings, and is most commonly used in industry. It can be conveniently used by the hand craftsman in conjunction with the screwcap washer when screwing plywood. The nature of plywood and sometimes its thinness makes it difficult to countersink neatly for a screw head.
For very small screws a four-sided awl is most convenient for the pilot hole. A touch of grease on a screw allows it to go in easier and by preventing rusting makes a later withdrawal easier too. Oak eventually has a corrosive effect on iron screws so for good-quality work brass screws should always be used.
Nancy Hiller – woodworker, author, teacher and friend extraordinaire – was recently diagnosed with pancreatic cancer. Champ that she is, she continues to write and design kitchens through the chemo treatments (and get out to the shop when the medical experts say it’s OK).
But as is the case with so many self-employed people in the U.S., Nancy’s medical insurance coverage isn’t sufficient, and chemo and other treatments are crazy expensive. After facing punishing medical treatments, she’ll be facing punishing medical bills.
Nancy would never ask for help. (Heck, I had to beg to help unload her truck when she visited Lost Art Press for a book release party a few years back.) So we’re asking for her. I know a lot of us are in tough financial situations right now – we may not be able to spare a lot. But if all of us who know Nancy through her writing, teaching, woodworking and life in general can each chip in just a little, we can make a big difference.
56:15 When you put a breadboard end on a table, how do you level the breadboard to the tabletop?
57:25 I’m making a field desk and am having trouble with tearout and tool marks on the African mahogany? Any advice?
59:10 What are your favorite woods to use?
1:00:40 What is the minimum air temperature for using your “shop finish” (equal parts varnish, boiled linseed oil and mineral spirits)? Can it be applied outside?
1:02:17 Could you expound on your new children’s books? What age range will they be for?