Making 18thc style screws for wood

[greg Forster]

How would I go about making 18thc style, small, i.e. 3/16" and smaller, wood screws? I have a lathe, but I don't think that is available to my rural cabinet-maker

[David Keller NC]

In the 18th century, a blacksmith forged screw blanks, and either the blacksmith, or in some cases specialized nail-makers would file the threads into the shank, shape the head and cut the slot. These types of screws are relatively easy to distinguish by the absence of a sharp point and residual file marks.

[george wilson]

Actually,they were manufacturing screws in England by the 18th.C.,in fact,the screw makers lost a lot of business from the colony during the American Revolution.

They had some kind of primitive fast and loose belt driven lathes,and had thousands of gross of screws in their warehouse overstock during the rev..

Of course,many also made their own screws. We found plenty of hand filed thread wood screws in 18th.C. guns that were taken apart for repair in the museum. They had bluntly chopped off ends rather than points,and often the tell tale off center screw slots. You had to drill holes to get those screws in.

[Johnny Kleso]

You would need a taper attachment..

I am not sure how they made screws back then but they may have been forged (formed) not cut..

Early 19th centery they had a milling head and cutter in stead of a just tool bit on a lathe with a taper attachment, they are called Thread Mills used only these days for very large threads..

[george wilson]

They were cut. Today these cheap screws we have are rolled. Actually,the deck and drywall screws,though ugly,are much better quality than wood screws made out of very soft,leaded steel.

Large screws,like lag screws would have been die forged. We made them that way for use on the 18th.C. fire engine reproduction.

[greg Forster]

I thank everyone for their input. What I'm wondering is how to make some small screws; both brass and iron, that are not just -" those look hand made", but those look like good 18thc reproductions" This is my main hobby, so I will sometimes spend "stupid" amounts of time on small details.

[George Neill]

Early screws were hand filed and had no taper. When the screwmaker was done, he snapped the screw off the stock (hence the rough end), moved it forward and began on another screw. I wrote a short post about early screw making (http://pegsandtails.wordpress.com/2009/09/18/fancy-a-screw/) which may be of interest.

[george wilson]

SOME were hand filed. Do you have any info on the factory manufacture of wood screws in Staffordshire in the 18th.C.? Edit: I read your post,and see you did.

Google wood screw making factory 18th.c.. The 2nd site from the top is a description of early screw factories. Even in America in the late 18th.C.. First screws factory made in England in 1760. I decided to Google it,but already knew it.

People who used just a few screws,or were poor,or way out in the country could still file out a few. There are just a few wood screws on a flintlock. Butt plate,and maybe trigger guard.

This question WAS about 18th.C. screws,not real early ones when they did make them by hand always.

George,your post talks about the screw factorys,and the screws you posted look lathe turned to me. Certainly the first one shown is,and its threads are even,and of the late flat bottom type. I suspect the short screws were turned on a lathe. The distortions in the threads look to me like the metal (wrought iron) could have gotten a bit irregular from distorting under the pressure of the dies.

The hand made screws I have seen over many years at the museum,had pronounced flat spots where the file was filed straight across,the screw rotated some,and more thread filed. As carelessly as they cut those off center slots,I must question how such good round pretty even threads could have been hand filed. Most of the old stuff looks like the workers were fairly drunk most of the time. I see this in old book bindings,very sloppily made and tooled,at a time when a bound book was about $2000.00.

Do you have any idea what metals and chemicals you are getting onto that poor dog,rubbing him on a mirror with handcream? I do hope that was a joke! Dogs are very sensitive to chemicals.

[George Neill]

Screws certainly were hand filed during the first half of the eighteenth-century. Even for after the introduction of screw-cutting machinery, screws continued to be handmade by smallworkers for a further couple of decades because a) machine made screws were expensive and b) the new products were not taken up immediately by all for various reasons.

The notion that poor or remote consumers filed out a few screws as needed is erroneous. Screw making was a specialised trade and unless individuals were set up with the requisite tools (the files would have been ludicrously expensive items) it just wouldn't have happened. I don't have the time to track down the references now, but there are records of cabinetmakers receiving supplies of screws from outworkers. The exception might be, as you alluded to, gunsmiths who would have most, if not all, the necessary tools to make their own screws.

The last two images in my blog article do indeed show lathe-made screws, but the others are definitely hand filed.

[George Neill]

George, you added two paragraphs to your last post between me hitting reply and my reply actually being posted.

Yes, I have seen those same angular-filed screws too. I'm sure you have come across plenty of examples of work that was well done and some that was not. Some workers accrue more skills than others and some take more care and pride in what they produce.

The dog… seriously?

[george wilson]

Pride,yes,but on a repetitive operation like screw making,I don't see how each screw would have been turned out to a high degree of finish. Even the screw's slots were carelessly cut grossly off center often. Why do you think a more demanding operation like filing threads would have been done to consistently higher standards? The many common items in collections I viewed for many years were pretty carelessly made in many instances,including saw handles,bound books of ordinary quality etc. The folding rule we copied was never used. It had out of order numbers stamped on it,and was sold anyway. I really think workers stayed tipsy quite a bit back then. It was about the only pain relief they commonly had. The multitude of wine bottles and fragments that have been found here testify to very wide use.

I'll have to agree with you about the first half of the 18th.C.,of course,but after 1760 plenty of screws were being mass produced. I am not thinking my best with this bad head cold.

[James Wilson Everett]

There is some additional research that you may find interesting concerning the 18th C. hand manufacture of metal wood screws. I am sure that you have noticed often that at the tip of the crest of 18th C. wood screws a small, linear line or joint running parallel to the thread. This line is a result of a cold swaging process where a hand tool is used to squeeze or swage the thread form onto a tapered wrought iron rod. During the swaging process the thread form valley is pressed into the soft wrought iron as the thread form peak is pushed outwards. At the end of the process the tiny line or joint remains from the process.

I have in my collection an original 18th C. wood screw swage tool that I use for making reproduction screws. The tool is an adjustable plier type with seven different slots for making different sizes. The finished product is identical to original 18th C. examples. I start with 19th C. wrought iron rod, actually oil well pump rod found near Oil City Pa. I file (or lathe turn) the tapered pin at a smaller diameter than the required finished screw, the thread will grow larger in diameter during the process. Next I close the thread swage on the pin and tighten. Then I rotate the tool while allowing it to travel up and down the pin on the pitch. As the thread is formed, I tighten the tool while rotating to complete the swage. The finished thread is tapered, square pointed and really smoother in the thread valleys than modern screws. There are no cutting chips resulting from the swage, nor is a file used to make the threads.

These 18th C. screws are really difficult to install, especially in hard wood. I do not cut the screw from the rod until after the thread is installed in the wood. The rod gives a good purchase for twisting the screw in. Lubricating the thread with wax is a real help, too. After the thread is installed, I remove it, cut the screw from the rod, shape the head and cut the screwdriver slot and reinstall the finished screw. This procedure prevents damage to the slot. I also have in my collection two different sized wood screw taps for forming the female threads in the wood during the installation process. This will greatly reduce the required force for twisting the screw in.

If you would like, I can send to you photographs of these tools and some finished screws.

[george wilson]

I am sure the Gunsmith's Shop in Williamsburg would be interested in seeing your swages. So would I,and no doubt Jay Gaynor,and the current curator of tools,Eric Goldstein. All in Wmsbg.. We swaged the lag bolts used in the 18th.C. fire engine reproduction. However,there are plenty of screws we have seen that were made by hand filing,or had factory made cut threads. This has been described in above posts. The threads I have seen in 18th.C. normal size range wood screws for 39 years were definitely too sharp to have been swaged. Often,too,they were still bright from being cut.

It is highly possible that BLANK screw bodies were swaged,then the threads cut. Swaging was easier to do than lathe turning the blank bodies out. It saved a great deal of metal,too,which was a lot more expensive then,being hand processed at the time.

No doubt some clever individual could have devised a different means of making his screws,especially as swaging was a common blacksmith practice. Screws were expensive,and worth putting inventive energy into. However,I very much doubt it was mainstream practice,not from the bright,sharp threads I have seen. Or,the sometimes faceted,file cut threads seen also,made by country craftsmen,or those too poor to afford factory screws.

How are you certain that your tools are 18th.C.?

[David Keller NC]

Here's a relevant article that some might enjoy reading. Particularly interesting is photos and characterizations of wood screws removed from furniture with well-documented ages:

http://www.wag-aic.org/Am_Wood_Screws.pdf

[Bill Rusnak]

The closest thing I've found to antiqure screws are at Lee Valley, but I think they're much bigger than what you are looking for.

200717

Search Pyramid Head Screw in Hardware.

I've also heard of people removing the zinc coating from modern screws with a vinegar bath and then filling the slots wider to give a "hand made" look.

Bill

[James Wilson Everett]

GUYS,

I have several scans of both the wood screw swage tool along with several screws made from the tool. I just sent them to a Mr. C. White who wrote a great article on 18th C. furniture wood screws. If you would like to see the scans I can send them, though I don't know how to do ity using this thread forum. I can send them by email, regular mail, or whatever. If you ever come through W. Pa. let me know and we can meet.

Jim Everett

[george wilson]

Can you scan them on a scanner/printer and get them into the computer that way? I'm no computer guy,but have done that a lot. We'd love to see these tools. What proof do you have that they are truly 18th.C.? I know Jay Gaynor would like very much to see them,as would I,and I'm sure,others here.

[James Wilson Everett]

Guys,

Here is a scan of an 18th c wood screw swage tool that makes 7 different sized screws. The threads swaged are clearly wood screw threads, not machine screws. The tool is 8 inches long.

Jim Everett

[James Wilson Everett]

Guys,

Here is a tapered blank for a #12 wood screw before swage, and the finished screw. The rod is puddled wrought iron put into service c 1860-1880 and recovered near Oil City PA. I turn the tapered blank on the wrought iron rod using a lathe, although a purist may use only a file. Next I close the swage tool on the rod, tighten the swage screw and rotate to tool. As the thread is formed the swage screw is tightened, there is no cutting or chips produced. The tool operates a lot like a modern tubing cutter. I install the screw in the wood before cutting it from the rod to give a good purchase for the installation torque. After installation I cut the screw from the rod and finish the head and cut the screw slot.

Jim Everett

[James Wilson Everett]

Guys,

Here are 2 screws made from the 18th c swage tool. The larger is about a #12 and is made from the largest size hole in the swage tool. I was shy to complete the swage process as the effort seemed high and I feared damage to this very rare tool. You can see that the thread is not fully formed. When completed the two edges of each thread would come together leaving only the tell-tale line at the crest of the thread form. This line is very often seen on original screws. When I need such large screws, like for a rifle butt plate, I use a tool that I modified from a much more common 19th c machine screw swage split die tool. I simply made a set of replacement split dies in the wood screw thread form. The smaller screw is about a #8 and is used for the rear of the trigger guard. Even smaller screws are a little more interesting, and frustrating to make using wrought iron, I have better results using modern leaded steel rod for the smaller screws.

Jim Everett

[george wilson]

Certainly an interesting tool.How can you prove it is 18th.C.,though? Also, it mashes the threads together,and may leave the tell tale little groove at the crest of the thread. I have not seen this on any 18th.C. screws that I have examined,but I may be forgetting what I saw as I haven't actively studied 18th.C. screws like I did when I was in my 18th.C. shop,trying to use 18th.C. tools only. Still,I can't infer that this was a mainstream type of tool for making wood screws. It is an adaptation on a way to make metal screws,and a clever one. As tall and large as wood screw threads are,compared to the much smaller threads of metal screws, I must wonder how long it would take to wear out the thread formers in this tool? Squeezing metal that much has to be hard on them. As you mentioned,you were afraid to use the tool too hard for fear of damaging it. The same would have applied when the tool was new.

[George Neill]

That's a very interesting tool, but I have not seen any eighteenth-century screws formed like that in my 35 years of working with eighteenth-century English furniture – maybe it was used by Americans. It looks to be well made; are there any markings or a name on it?

[James Wilson Everett]

Guys,

Thanks for your interest in the wood screw swage, I will try to answer your questions one at a time.

1. It is difficult to date any unmarked tool, especially when one is nearly unique. But I feel sure that the screw swage was in use prior to the mass production of wood screws and probably before the availability of machine/lathe cut screws. The only markings on the tool are the engraved numbers 1-7 for the different swage positions.

2. Check the good reference link at D. Keller's response of 07-05-11. This links to a great research article by C. White, Observations on the Development of Wood Screws in North America. Look closely at the screws shown on page 10 and 11, both from the late 18thc early 19thc. The screws clearly show the swage line at the crest of the thread. The screw on page 10 is really incompletely formed as the two sides of the swage do not quite meet to form a line, very simliar to the screw shown in one of my scans.

3. I have made about 100 wood screws using both the original tool and my 19thc swage with new dies. I have not noticed any wear on the dies, although they do require cleaning with a brush, I use a .22 caliber bore brush, to get the junk out of the swage crest areas.

4. Lathe cut threads will tend to be very rough in the thread valley since the lathe cutting tool is cutting 90 degrees opposed to the wrought iron grain in the rod. Any time I have done lathe cutting on wrought iron rod there is a definite roughness to the cut surface, when using leaded steel rod the cut surface is much smoother. When using the swage tool the thread valley is nicely smooth and somewhat polished while the thread crest tends to be sharp and rough, likely to cut your fingers.

Jim Everett

[George Neill]

Jim, I'm afraid I don't see what you see. The images on pages 10 and 11 look like any other rough-turned taper shank lathe-turned screws I have seen – which is how the supporting text describes them too. The text even mentions the burrs on the threads caused by the cutting process.

Like you, I have seen rough surfaces on lathe-turned wrought iron, but conversely, I have seen a significant number of rust-free eighteenth-century screw threads with smoothly turned surfaces.

[Jim Koepke]

Jim, I'm afraid I don't see what you see. The images on pages 10 and 11 look like any other rough-turned taper shank lathe-turned screws I have seen – which is how the supporting text describes them too. The text even mentions the burrs on the threads caused by the cutting process.


I am not the Jim referred to in George's post. I do see similar markings to the screws formed by using the swage tool.

Here is an image from page 10. There does appear to be separation at some of the peaks of the threads.

It might be clearer in an enlarged image.

202540

I do not see any mention of burs left by cutting on page 10 or 11.

I am wondering how unique the swage tool may actually be. Having an ability to make screws faster than another cabinet shop may have been an advantage the maker of such a device might not want to share.

Once a less expensive way to make screws appeared, having such a tool would not be an advantage.

[James Wilson Everett]

Guys,

I am really pleased at the great responses to the screw swage, I think that this is an obscure corner of information that really needs to be resurrected and thoroughly explored. This is a scan of the 19thc machine screw swage tool that I modifed to make the larger wood screw threads. Remember that in an earlier post I am shy of damaging the older tool due to the high force required to swage the larger threads. On this tool I removed a pair of the machine tool split dies and replaced them with a pair that I made for the wood screw threads. You can see the diffferent split dies on the scan. The material is 1095 carbon, hardened and tempered to dark straw. I machined a large female wood screw thread using a boring bar on a lathe, then split the die into the two halves. I polished the thread valley, that is the smallest diameter of the split dies, to give the rounded thread valley like the original screws. I close the split die on the tapered wrought iron pin and rotate the tool while keeping it level and allowing it to move parallel to the pin centerline. It takes several passes with several tightenings to swage the threads. It only takes a minute to do this. Make your own and try it.

Jim Everett

[george wilson]

I see the lines you mention in your screw. They had similar die holders in the 18th.C. for metal. I don't see why someone couldn't convert one for wood screws like you did(but back then).

About cutting threads in wrought iron,they can be cut smoothly if you do them right. Also,I have used very old wrought iron samples,and more recent samples taken from structures like bridges. There is a BIG difference in the quality of the wrought iron. Real old wrought iron from gun parts files and turns much more nicely than the structural wrought iron. The structural stuff is gummy,and pins up the files badly.

We used samples of different wrought irons over the years a Williamsburg. It definitely isn't all the same. Since wrought iron was the prominent forgeable metal that they had at that time,they had a lot of different varieties available to them. Several different grades were imported from Sweden alone,with significant differences in cost. English wrought iron wasn't so good because of the sulfur content in it,which rendered it "hot short" for forge work. Since they knew little about chemistry until about 1830,they did not know how to improve the domestic product. Spanish iron was thought to be better due to the AIR in Spain!

Poor grades of wrought iron are better swaged into threads than cut,because the excessive amount of inclusions in it causes the threads to fall off. We made screw plates for the gunsmith shop that swaged the threads on. Perviously,they wasted a lot of labor FILING out screw blanks for metal screws,and then trying to cut the threads with more modern types of dies. The threads just would fall off sometimes.

The wrought iron they have to use in the museum are from old bridges,etc.,and just not good grades of the metal.

[John Toigo]

You might look here: http://www.blacksmithbolt.com/gpage14.html They have an interesting assortment.

[David Keller NC]

You might look here: http://www.blacksmithbolt.com/gpage14.html They have an interesting assortment.

John - Thanks greatly for that link. I've been resorting to cheap 'n crappy slot-head zinc-plated wood screws from the Home Despot for my projects and stripping the zinc off with citric acid. But these screws are really soft and gummy, and are not available in many sizes. And I refuse to put philips, torx, or square-drive screws in an 18th century repro. I'll give these guys a call.

[James Wilson Everett]

Guys,

Here is the 19th c machine screw swage tool that was modified by replacing a pair of split dies with a new set to make wood screw threads. remember in an earlier post that I am shy to use the older tool to make the largest threads because of the risk of damage. The new dies were machined from 1095, hardened and tempered to dark straw. I cut female wood screw threads in a block using a lathe boring bar sharpened to a point. Next I cut the block in half to make the split dies. I polished & rounded the die threads to give the rounded valley thread profile of 18th c wood screws. The tap I use to tap hard wood, like sugar maple before installing the wood screw. Try this yourselves.

Jim Everett

[James Wilson Everett]

George,

I know what you mean about differing pieces of wrought iron. The only reason I have been using the oil well pump rod is that it is in about 5/8 inch diameter rod already. It is rather coarse in that the slag strings are large. It works great for the large screws but the smaller screw threads tend to break away in the swage process. The leaded steel rod works great, but it is the wrong stuff. I do have a wagon wheel rim that has such fine slag strings that they cannot be seen even on a polished surface. They only are obvious after a long etching with muriatic acid. Rather odd that such a XX refined piece is in a wagon wheel rim. I will try this piece to make smaller screws and see how it does, hopefully better.

Thanks for your wise advice,
Jim Everett

[george wilson]

You probably already knew it. I was mostly talking about wrought iron grades for the benefit of others who might not as much about metals,especially obsolete ones.

By the way,wagon tires get compressed badly. Are you sure the lines in the tire are slag lines,not compression? I'll bet we helped replace 100 tires in Wmsbg. They get run to death every day.

[James Wilson Everett]

George.

I have made another attempt to swage smaller screws using the 18th c swage tool and real wrought iron. The photo shows the two previous screws and the new smaller one. The largest is about a #12, .23 diameter swaged in hole #1, it was easy to swage, but I stopped short of completing the swage fearing damage to the tool. The middle size is about a #8, .17 diameter swaged in hole #3. Both of these screws used the coarse wrought iron oil well pump rod. The smallest is about a #6, .13 diameter swaged in hole #4. This one used much finer wrought iron from a blacksmith tong handle that showed very fine slag streaks. I tried to swage an even smaller screw in hole #5 using wrought iron, but failed as I twisted off the shank. I seem to be too heavy handed for the smaller screws using real wrought iron. I have made several smaller screws using leaded steel rod, it is much more forgiving of my clumsy effort. The smallest screw I have made in leaded steel is about a #4, .09 diameter swaged in hole # 5 for a wood patchbox spring. I have not even tried holes # 6 or 7.

You were certainly correct in that a finer grade of wrought iron is easier to swage, thanks for the tip.

Jim Everett

[george wilson]

James,are you using any kind of lubricant in swaging your screws? I know that in the 19th.C.,at least,they used soapy water in England to drill holes in armor plate with carbon steel drills. Must have been a slow process,and I'm sure the sharpeners were kept busy.

[Ryan Mooney]

I recall as a kid us making some larger "screws" (really lags I suppose) by straight forging. Hammer a rod till lightly tapered and shaped sort of like <> in cross profile (actually hammer one side, turn hammer the other and you get a bit of a flared cutting edge on the thread once twisted if done right, take that into account in considering twist direction). Twist hot to form the "threads" and cut off and upset the end to make the head. Takes a bit of practice to get the twist even though (heat the thicker end a little more than the thinner, the color tells you when its right :) and I can't imaging doing it for pieces smaller than maybe 1/4". Its been ~20+ years since I've seen this done and I don't have a spot for a forge nowdays.. so no pics... just vague recollections.

[James Wilson Everett]

George,

Yes, I use heavy grease (the modern stuff) when swaging. It really is necessary to use some sort of lubricant to get a decent result. But, I havent tried soap, maybe next time. I believe that the flaw is in the design of the swage tool itself. If you look at the scan of the tool you can see that the greatest leverage applied from the adjustment screw will be on the smallest thread size, while the least leverage will be on the largest thread size. Mechanically this seems to be backwards. The swage tool would probably function better if the order of thread sizes were to be reversed with the smallest thread size closest to the adjustment screw and the largest thread size at the greatest distance. This may solve the problems of the high stress while swaging the large screw and twisting off while swaging the smaller screw.

However, since this is the one and only wood screw swage that I have seen after searching for many years, I must be content.

Jim

[george wilson]

You are correct. The tool is backwards.

[James Wilson Everett]

Guys,

Here is an old screw, about a #10, from a Tulle trade gun c. 1760. The scans are both of the same screw. You can see the swage line where the two sides on the thread just miss meeting at the crest of the thread. This only happens from swaging, not from filing. Also, The diameter of the largest thread is larger than the shank above it that has no threads. As the thread is swaged the crest will grow outwards duing the process making the thread larger than the original shank. Check out any 18th c screws you have by closing a dial caliper with the thread shank parallel to the long dimension of the caliper jaw (90 degrees from the way you normally check the screw diameter). You may see gap between the unthreaded shank and the caliper jaw here showing the thread is actually larger than the shank. Check it out.

Jim Everett204361204362

[James Wilson Everett]

Guys,205259

Here is a scan of a screw swage tool taken from a catalog of tools for clock makers, John Wyke of Liverpool, England. The catalog dates from the third quarter of the 18th century. As can be seen, the tool is very similar to the swage tool original shown in an earlier scan. The Wyke tool uses a hinge to align the two tool halves together whereas the original tool is of one piece. Both tools are used in the same manner to form a tapered thread by swaging. The Wyke catalog does not state the screw sizes or thread form of the tool, but it is assumed that it is for making tapered threads - wood screw threads.

Thanks for your interest and comments - keep it up!

Jim Everett

[george wilson]

You must admit,though,clock makers used screws for metal much more than a few screws for wood! I don't see why it wouldn't apply to wood screws as well,though. Your other tool does.

I have seen simpler screw swaging devices for metal screws. One that pops up once in a while was a "U" shaped device with enlarged chops that was clamped in a vise,and could be squeezed by the vise as the thread was formed. The only examples I have seen were for metal threads,though.

[James Wilson Everett]

Guys,

Here are some more photos of old screws to help in understanding the way they were manufactured. The first is from an English trade gun butt plate, c. 1760, and is certainly made by the swage process. The second is from a percussion rifle, c. 1850, and is certainly made by a lathe/thread cutting machine process. The third is from a French Tulle trade gun, c. 1750, and is most probably made by a filing process. Look closely at the notes on the photos to see the differences.

Jim

209028209029209030

[george wilson]

James,are you getting any where with Jay Gaynor? Let me know if you manage to set up a demo there.