We always need to hold things together – but should it be screws or nails?
There has never been a time when so many different kinds of fixings have been available. It runs into many thousands, but just two dominate our thinking when we are repairing or constructing anything in wood. The good old-fashioned nail pitted against the newer, more sophisticated screw. Is that really correct? What are the advantages and disadvantages?
Nails
Nails have been around for many millennia, they are cheap to make and buy, and use a hammer and the kinetic energy from our muscles to bury them in wood. They come in a variety of types from veneer pins, upholstery tacks, oval nails, wire nails and ring nails, right up to long contraction nails. Today, you can buy nails powered by air, gas, explosives or battery. So, do they still have a place in the world?
Nails seem crude by today’s standards, as does using a hammer and risking hitting your fingers and thumbs. On the other hand, for a quick result if you develop the right technique they still do the job, powered nailers are even quicker. Wood splitting is the bane of fixing, but a key thing is to start nailing away from the end of the wood. If nails are driven in very quickly with a powered nailer, the chance of splitting reduces because the wood fibres have less time to react to the intervention of metal in the wood. A long standing fault of the nails is their tendency to pull out easily. Ring nails are designed to counteract that to some extent. In earlier times, cut nails were used to fix skirtings and so forth, to masonry; the square shape being able to bite into brick and mortar. Sadly, modern cut nails don’t seem to do the job anymore. There are special hardened masonry nails if you need to use them.
Screws
Screws have been around quite a long time, originally hand-cut but quickly succumbed to mass-manufacturing. Screws have become a very diverse family of types with every conceivable thread, shank form and head shape. Traditional steel and brass screws have a tapered form, which requires two drill sizes – pilot and clearance – and then a countersink for the recessed head. Modern single or twin fast screws often don’t need any pre-drilling, if they do it is a single pilot drill and no countersinking as the heads now often have cutting edges under the head to dig their way into the wood. The driving interface in the head has become just as important. Traditional slots easily burr over when they are hand driving and the screwdriver tip can slip out and skid across what may be a beautifully finished surface. Instead, we have other recesses, the most common is the Pozidrive, otherwise known as Pozi, and comes in one, two and three sizes to suit the head size. Factory produced items use simpler Phillips recesses or Torx, which are typically used by double-glazing companies but increasings are used with wood too. A major advantage is no ‘cam-out’ – the driver tip cannot slip out of the recess, but unlike Pozi and Phillips there is no possible offset driving angle. This is both a good and bad thing since it is offset driving that causes ‘cam-out’. You may encounter a Torx variant that has a pin in the middle as a security feature, it needs a matching driver tip. There are other cross-head types often described as ‘stick-fit’ because of close tip and recess tolerances. These come with their own special driver tip in the box, but may accept Pozi driving tips as well.
Returning to the shank of these modern screws, the better ones have a slit near the tip to allow them to cut into the wood, and some have frilled flutes designed to break up the wood fibres as they drive into the wood. Many are also dry lubricated so they go in without effort or pre-drilling and they are strong enough not to snap when they’re power-driven. If such a screw is withdrawn, it will heat up and more so if it is immediately re-driven as the lubrication is lost.
Some answers
So, screws vs nails – which is the winner? Speaking from personal experiences, life has got a lot easier with ‘first-fix’ carpentry using nail-on joint plates, and long timber screws with just a thread at the tip and a hex head on the top when power-driven with a socket driving bit. Gone is the need for a repeated arm aching, hand hurting 26oz hammer blows and slamming 100mm or 150mm nails into timber framing. Upholstery and the like can often be done with a heavy duty stapler, although tough upholstery tacks on a hardwood seat frame still win. For general work, oval nails are useful because they cause less splitting and the heads can be lost by punching into the wood. Panel pins and veneer pins yes, but wire nails – except in power nailers – seem largely irrelevant.
For general carpentry and cabinetwork, choosing the right quality and type of twin fast screw gives neat, efficient results quickly, but for fine cabinetwork slotted brass screws run into carefully pre-drilled and countersunk holes after using steel screws first (to ensure the weaker brass screws go in smoothly) still wins. Indeed, I am fanatic about settling slots at the correct angle – I prefer them to alternate, though without over stressing the screws.
Overall, the nail isn’t dead and won’t be anytime soon, but it does seem as if the screw is the modern day winner; it has certainly changed my working habits.