The Humble Turnscrew........

Posted by Tobias Lochner on

Now he has really lost the plot, I hear you mumbling..... 

What in the world is a "Turnscrew" and why would I be lost without mine?

Delving into the histories and mysteries of woodworking tools is truly a lot of fun and surprisingly fascinating!

We need to go back a little in time, to around the mid to late 15th century, somewhere in middle Europe to begin our mini voyage of discovery.

Early Male Thread Cutting Machine

The screwdriver's original names in German and French were Schraubendreher (Screwturner) and Tournevis (Turnscrew), respectively.

The first documentary evidence of this remarkable tool that we take for granted today, is in the medieval Housebook of Wolfegg Castle , a manuscript written sometime between 1475 and 1490.

Early Ebony Handle  Turnscrews

The earliest screwdrivers had pear-shaped handles and were made for slotted screws.

Gunsmith's Turnscrew Tool Set

The diversification of the many types of screwdrivers did not begin to emerge until about 1870. The screwdriver itself remained somewhat inconspicuous, however the evidence of it's existence throughout the next 300 years, is based primarily on the historical evidence of the screws themselves.

 

Screws were used in the 15th century to construct screw-cutting lathes and for securing breastplates, backplates, and helmets on medieval jousting armour, and eventually for attaching and holding parts in the emerging manufacture of firearm products, notably the Matchlock Gun.  

On a Matchlock, the jaws that held the Pyrite (the cock of the weapon held a lump of pyrite against a circular file to strike the sparks needed to fire the gun) in medieval guns were secured with screws, and the need to constantly replace the Pyrite resulted in considerable refinement of the screwdriver.

Set of Antique Duelling Pistols

Note: Turnscrew in the upper right corner

The screwdriver is more widely documented in France than elsewhere, and took on many shapes and sizes, though all for slotted screws. There were large, heavy-duty screwdrivers for building and repairing large machines, and smaller screwdrivers for refined cabinet work and guns.

The screwdriver depended entirely on the development of the screw for it's own metamorphosis, and it took several technological advances to make the screw easy enough to produce, thus becoming popular and widespread.

Screws were very difficult to produce before the first Industrial Revolution, requiring the making of a conical helix. The brothers Job and William Wyatt, found a way to produce a screw on a novel machine that first cut the slotted head, and then cut the helix. Though their business eventually failed, their contribution to the low-cost manufacturing of the screw, ultimately led to a vast increase in screw production and usage, and ultimately the screwdriver's popularity.

The increase in popularity gradually led to refinement and to the  eventual diversification of the screwdriver. Refinements in the precision of screws, also significantly contributed to the boom in production, mostly by increasing efficiency and standardising the sizes, which were critically important precursors to full scale industrial manufacture.

Many gunsmiths still call a screwdriver a turnscrew, under which name it is an important part of a set of pistols. The name was common in earlier centuries, and was widely used by cabinetmakers, shipwrights, and many other trades. The cabinetmaker's screwdriver is one of the longest-established handle forms, somewhat oval or elliptical in it's cross section. The purpose of this design is two-fold, firstly, it helps dramatically to improve the user's grip, a secondly, it doesn't roll off your workbench!

Screws are relative newcomers to the production of furniture and did not become a common woodworking fastener until more efficient tools were developed around the end of the 18th century.The shape has been popular for a couple of hundred years. It is usually associated with a plain head for slotted screws, but has been used with many head forms.

In the image above, the screw on the left was hand-made and one on the right was machine-made.

There are many differences between a handmade and a machine-made screw. The shank of a handmade screw does not taper. The point of the handmade screw is blunt. By contrast, the shaft of the machine made screw tapers to a point. The threads are cut evenly and they pitch at a different angle than those of the handmade screw. 

The first record of a manufactured screw was in England sometime around 1760. The original patent outlined the use of a lathe and a set of metal cutting tools, which were repeatedly run over the shank of the screw blank to cut the threads, which facilitated hand production. Many of these screws were flat bottomed, until some bright chap had his "Eureka Moment" and realised that a pointy end worked better as a fastener!

Screws that were made from about 1812 through to the mid-1800's were partially machine made, giving the threading a more even appearance, but the heads were still finished with hacksaws, to add the groove to fit a turnscrew / screwdriver. As is the case with screws made even earlier, no two screws are exactly alike.

Around the time of the Industrial Revolution, from about 1860, the method of making nails, screws, hinges, latches, and of milling lumber often changed. Each change was well documented, and most of them were patented. The style of nails changed a dozen times, the hinge changed four times, the screw changed three times, and so did latches and pulls. The methods of working wood also changed during this time. The saw changed, moulding styles changed and mortising also changed.

Back to the Present:

Modern plastic screwdrivers use a handle with a roughly hexagonal cross section to achieve their combination of torque and a comfortable grip, a far cry from the pear-shaped wooden handle of the original 15th century screwdriver!

Today, we are inundated with a vast range of slot head screwdrivers, but only  very few of them actually turn a brass screw into a piece of wood, cleanly and without damaging the screw head.

It is time to do yourself a massive favour: Get yourself a good set of Cabinetmaker's Screwdrivers! You will thank yourself over and over in your workshop.

Today you can buy decent, high quality Cabinetmaker's Screwdrivers in South Africa. Crown Tools, imported by BPM Toolcraft on the request of local cabinetmakers, offers beautifully made Cabinetmaker's Screwdrivers in various sizes that will last you a lifetime.

Here are the basic notes to bear in mind for slot-head screwdriver usage:

  • Always select the screwdriver that best fits the screw head; the tip must fit the slot securely with no overhang on either side. The thickness of the tip must match the slot width, if the fit is wrong, the screwdriver will slip and damage itself, the screw and the work, as well as cause you injury. 
  • How the handle fits your hand determines the amount of torque and pressure that can be applied. Round-ish handles that are generally made of plastic do not really provide a long term comfortable grip or high torque ability. 

Proper Cabinetmaker's Screwdrivers are wonderful tools, and are not simply leftovers from a bygone era. In fine woodworking, brass slot head screws are regarded as standard hardware. Using an impact driver or drill/driver on brass screws usually results in disaster as the brass is not strong enough to resist the high instantaneous torque offered by these machines. 

Gunsmith's screwdrivers are widely used in woodworking, mainly because of their excellent tips (mostly hollow ground) and their short length, giving the user fine control. Narex makes wonderful hollow-ground gunsmith's screwdrivers with knurled brass ferrules, in three sizes and they are in stock at the Toolcraft shop and online store.

When it comes to buying a decent set of general screwdrivers for woodworking, I have yet to come across a better value for money set than Narex Screwdriver Set. Not only does the set cover most of the popular tips, but is incredibly well thought out. I have used these screwdrivers for a little over a year and I am extremely happy with them.

These are simply put, clever screwdrivers. The shafts go right through the handle so that you can hit them safely with a hammer to start a stubborn screw when removing it, without damaging your screwdriver! (If you really have to!).

There is a leather washer between the handle and where the shaft enters the handle, for efficient shock absorption. These screwdrivers also feature brass plated steel ferrules and, here is the best bit.... They have a welded in hex nut at the base of the shaft where it exits the handle. This offer you the facility of added torque by helping the screwdriver with a spanner - very intelligent!

I have the set of 5 Narex screwdrivers and I really love them. They don't roll off my workbench, get heavy daily use, the tips are still crisp after a year and the very best part is they don't cost an arm and a leg! Narex also offer single screwdrivers including Robertson style for square socket-head screws, Pozi Drive & Phillips style.

 

Considering the remarkable evolution of these seemingly simple everyday tools and being a daily user of brass and steel screws, I fully recommend using the correct screwdriver for the correct screw, (at the price of good quality brass screws these days, I basically can't afford not to!) 

My screwdrivers of choice are:

  • General work and small brass & steel screws- Narex Mixed Set  & Narex Gunsmith Screwdrivers. Intelligently made and very well priced.
  • Larger Brass Screws - There is no substitute for proper Cabinetmaker's Screwdrivers and the Crown models are well priced and work beautifully.
  • For tightening my backsaw handles: Lie-Nielsen's Tenon Saw Nut Driver
  • For opening tins of paint and varnish: Anything that has a plastic handle!

Until next week, let's make shavings, not dust!

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8 comments

  • Hi Johan and welcome to my blog. I agree with you wholeheartedly regarding the screws all facing the same way! Some years ago, I made a 4m x 5.2m deck for a German friend for their Jacuzzi and gas braai area. There were a couple of thousand brass counter sunk screws in the project, and yes, they all faced the same way, (I think it was North-North-East). I learned later that when the couple were showing off their new deck, the lady of the house repeatedly made a big thing about the screws and nothing really about the deck itself! I got three contracts based entirely on the time, effort and pride put in on those screws. (The craziest part was that I used a Yankee screwdriver and standard screwdrivers to do the whole job, I really am a blighter for punishment!)

    It is sad that we were not taught about screws and how to use them properly at school. I do agree with you about using combination countersink drill bits. The best ones that I have seen, but not yet had the opportunity to try (Brian and Alison: Are you listening?) are the Veritas units, which have a tapered drill shank combined with the countersink. This makes complete and logical sense to me. You suggest soap on the thread, it works really well, simply scraping the screw thread lightly across a dry piece of soap helps dramatically. I sometimes use paste wax or candle wax as well. (Whatever I have to hand). Thanks so much for bringing up the points about slot screw head angles and thread lubrication. Greatly appreciated.

    Tobias Lochner on
  • This is very interesting and well researched tutorial, thank you Tobias, All the comments are so valid when using screws and the drivers to match, from experience I had to figure out the correct pre-drilled hole size to match the screw thread and to include the shaft length and diameter for the screw to align and hold correctly. There has been so many occasions when the screw is broken off or the slot has been marred by a stubborn screw and the wrong screw driver being used. Again it was never really taught at woodwork school level! Some helpful tips I gather during the years are: 1. using a Drill/shaft/counter sink combination cutter. ( Stanley used to make quite good ones and there are Dimar and others.) 2. Using soap on the thread for easier driving into the correct pre-drilled hole! 3. lastly the sign of a good craftsman is to leave all the screw slot’s facing the same way and aligned with the grain direction. Just some thoughts!

    Johan on
  • Hentie, you make an incredibly important point! With the power tool revolution since the 50’s, there have have been fundamental headspace changes in woodwork.

    It’s the idea that our machines will do it right, first time and every time. However, this only really happens with proper planning, accurate marking out, careful setup, sharp blades and cutters, effective workpiece & tool control and correct cutting speeds. I would argue that this process is no different from using hand tools.

    In my school woodworking class, the hand planes, chisels and saws were all dull. I would also go as far as to say that the try squares were not truly square. We all wanted to use the table saw, lathe and bandsaw. We weren’t taught sharpening, or the advantages of marking knives over pencils. So I suppose we were introduced to woodwork from maybe the wrong angle. When I teach, I start with the basic instruments of the trade and how to get them to do their job properly. Only with sharp tools, accurate layout instruments and care can we actually begin to do woodwork well, whether using hand tools or power tools, or even big machines.

    Tobias Lochner on
  • Whoaa Tobias – that was informative. Unfortunately it seems we have a cycle of learning and forgetting (with maybe a portion of this is the way we do it – because its the way it has allways been done/the way I was taught) It seems a lot of knowledge is forgotten with the move to power tools, that is being discovered on moving back to hand tools.

    Hentie on
  • Hi Brandon and thank you for your positive comments. Your points on screwdriver tip care are extremely important. I see that Hentie has suggested that you write a blog post specifically on the subject. This is a great idea. I am also eager to learn the finer points of dressing my screwdrivers. Quality screwdrivers should last a lifetime when properly cared for. I think we shall call your first post "Brandon"s Dressing Tips"…….Or not!

    Tobias Lochner on

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