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General discussion => Tutorials => Gunmaking tools and techniques- metal shaping => Topic started by: James Wilson Everett on October 24, 2011, 03:42:02 PM

Title: Making 18th c wood screws
Post by: James Wilson Everett on October 24, 2011, 03:42:02 PM
Most wood screws in the 18th century were made by the hand swage process using a split die tool that is similar to the tool used to make lock screws, but the dies were made to form wood screw threads.

Below is a photo of an original butt plate screw made by the swage process.

(https://i1137.photobucket.com/albums/n514/JamesEverett/notedEnglish.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/notedEnglish.jpg.html)

Below is a photo of an original screw butt plate screw made by the filing process, the differences are obvious.

(https://i1137.photobucket.com/albums/n514/JamesEverett/notedTulletop.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/notedTulletop.jpg.html)

A typical original tool to make the swaged wood screw threads is shown below, unfortunately for those who actually want the claim a "hand made" status for their guns, these tools are extremely rare.

(https://i1137.photobucket.com/albums/n514/JamesEverett/oldtool1.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/oldtool1.jpg.html)

I make my wood screws for the butt plate from 19th century puddled wrought iron.  The following sequence of photos shows the forming of the wood screw threads on a wrought iron tapered pin.  The pin was turned on a lathe, but can be hand filed for the true purist, of course.


(https://i1137.photobucket.com/albums/n514/JamesEverett/Process1.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Process1.jpg.html)

(https://i1137.photobucket.com/albums/n514/JamesEverett/Process2.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Process2.jpg.html)

(https://i1137.photobucket.com/albums/n514/JamesEverett/Process3.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Process3.jpg.html)

(https://i1137.photobucket.com/albums/n514/JamesEverett/Process4.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Process4.jpg.html)

(https://i1137.photobucket.com/albums/n514/JamesEverett/Process5.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Process5.jpg.html)

From this point I install the screws in the butt plate while still attached to the rod and do not cut the screw from the rod until later.  This saves damage to the screw slot from the very high installation torque when installing a tapered 18th century wood screw.  The swage tool makes seven sizes of wood screws, the smaller they are the more difficult because they tend to twist off during the swage process.  Really tiny screws, like for the wooden patchbox lid spring, I make using leaded steel as it is much more forgiving for my clumsy efforts than real wrought iron.

Also, I have in the past made wood screws by the filing process, but have repented of that since locating the swage tool.

Jim Everett
Title: Re: Making 18th c wood screws
Post by: alyce-james on October 24, 2011, 04:19:00 PM
Mr. Everett: Thanks for sharing one of the most interesting and informative tutorials I've seen on this site. Your chosen topic was so interesting to me I when through maybe three times. Outstanding picture presentation. Thanks for posting. Jim
Title: Re: Making 18th c wood screws
Post by: The Original Griz on October 24, 2011, 05:49:14 PM
ya all want to pay attention when Jim tells ya something, He is one fine Gun maker and I am proud to call him a friend. I even saw him make some of those screws. It is a very interesting process, it does not cut threads like the modern dies do....
Glad to see you on the forum Jim, Griz AKA the horner from mountain craft days.
Tim
Title: Re: Making 18th c wood screws
Post by: roamer on October 24, 2011, 06:52:56 PM
This is what I love about this website,the sharing of knowledge ,detail and sharing . Thanks
Title: Re: Making 18th c wood screws
Post by: KNeilson on October 25, 2011, 02:20:47 AM
Jim ,thx for the pics, interesting subject. I would be interested in a close up shot of the swage plate. I have some smaller die plates for making round threads, have always wondered about tapered ones............  regards..   Kerry
Title: Re: Making 18th c wood screws
Post by: John Archer on October 25, 2011, 02:40:06 AM
Great photography Jim!

I too would like to see some detail pics of the swage plate if possible.

John.
Title: Re: Making 18th c wood screws
Post by: James Wilson Everett on October 25, 2011, 05:24:10 AM
Guys,  Thanks for the interest in making the wood screws. Here are some more photos of the 18th c swage tool along with a shop user tool that I made from the far more common 19th c machine screw split die swage tool.

The original tool has no maker mark, only the numbers 1 through 7 for the different screw sizes.  It was probably made by a professional wood screw swage tool maker, not by a blacksmith or gunsmith.  The numbers are die stamped, notice the double stamp on the number 5.  Even the old timers made oops.  Also, to make the tool requires seven hardened taps of a wood screw form, not likely to be owned by a gunsmith.  A nearly identical tool is shown in the John Wyke tool catalog circa 1750.

(https://i1137.photobucket.com/albums/n514/JamesEverett/100_4647a.jpg)


(https://i1137.photobucket.com/albums/n514/JamesEverett/100_4646a.jpg)

The original tool is so very rare that I do not like to use it to make "production" screws.  I modified the common 19th c machine screw swage by removing a pair of dies and replacing them with a set I made to form wood screw threads.  I made a hardened wood screw tap, threaded a hole in a plate of 1095 carbon steel.  Cut the plate into two halves and fit them to the tool.  The new split dies were hardened (1500F, brine quench, drawn to medium straw).  This tool works OK, but the threads are not as pretty as those made by the original tool, but I do not fear damage to the "production" tool.

(https://i1137.photobucket.com/albums/n514/JamesEverett/100_4648a.jpg)

Jim Everett
Title: Re: Making 18th c wood screws
Post by: KNeilson on October 25, 2011, 06:02:48 AM
Perfect,  just what I wanted to see.  Great explanation too.  Thx Jim.......   Kerry
Title: Re: Making 18th c wood screws
Post by: Glenn on October 26, 2011, 06:35:40 AM
I've been wondering for years how these screws were made back then.  Thank you very much for taking the time to post this interesting information.  I've finally got the answer to my question.  I agree with you too; I wouldn't use the original too neither.  I'd replicate it (as it seems you've already done) and then use the replicated piece for production screws.  Your swaged screws look great by the way.   ;D
Title: Re: Making 18th c wood screws
Post by: James Wilson Everett on October 26, 2011, 03:25:58 PM
Guys,

Here is some additional information on the 18th c wood screw topic.  For anyone who has really reproduced an 18th c gun, they know how difficult the tapered wood screws are to install without damage to the screw slot.  With a modern non-tapered screw only the lead thread does the cutting/forming of the wood, the subsequent threads just follow the path.  We all have installed modern wood screws.

With a tapered 18th c wood screw all of the threads are cutting/forming since each subsequent thread is slightly larger than the previous.  This is why I try not to cut the screw from the rod until after installation.  Then I cut the screw from the rod, shape the head, cut the slot, then reinstall the screw.

Here is a photo of 18th c wood screw taps used to form the thread path in the wood prior to installing the wood screw.  These clearly have wood screw threads, not machine screw threads.  Also, they are not hardened so could not have been used to tap threads in metal.  At some time during their life some bonehead tried this with the smaller tap and damaged the soft threads (not me!!!)


(https://i1137.photobucket.com/albums/n514/JamesEverett/100_4650a.jpg)

Jim Everett
Title: Re: Making 18th c wood screws
Post by: alyce-james on October 26, 2011, 05:27:29 PM
Mr. Everett; More shared educational information passed on. I find this shared knowledge of great interest to many of us who have wondered about this very subject. Thanks for this very successful informed transfer of knowledge. Jim
Title: Re: Making 18th c wood screws
Post by: T*O*F on October 26, 2011, 06:42:10 PM
Quote
For anyone who has really reproduced an 18th c gun, they know how difficult the tapered wood screws are to install without damage to the screw slot.

These are 19th century English tapered screws.  I have no idea how they were made as the man is now deceased.  They require a special countersink as the head angle is different than American wood screws.  During initial  installation, temporary slots are cut in the heads.  Once fitted, the heads are filed down and new slots are cut in the proper clock position.

(http://i102.photobucket.com/albums/m104/ML-L/ALR/Dsc00089.jpg)

I use these for initial installation of the wood screws.  The tang and standing breech screws require a long tapered reamer to make the proper sized, tapered  hole thru the wrist and underside of the gun.

(http://i102.photobucket.com/albums/m104/ML-L/ALR/Dsc00088.jpg)
Title: Re: Making 18th c wood screws
Post by: Dphariss on December 01, 2011, 06:04:39 PM
Very interesting and informative.
Getting/making decent wood screws is an ongoing PITA from my point of view. One of these thread formers would be very useful to say the least.

Dan
Title: Re: Making 18th c wood screws
Post by: Obediah on December 01, 2011, 06:39:16 PM
This has been one of the most informative tutorials I have read anywhere. It clears up a lot of questions I have had in my mind for a long time. Thanks.
Title: Re: Making 18th c wood screws
Post by: James Wilson Everett on December 02, 2011, 02:58:17 PM
Guys,

Last month I demonstrated this wood screw swage for the craftsmen at Colonial Williamsburg.  They seemed to be very interested and plan to make at least one copy of this tool for their use in the gunsmith shop.  Also, we spent some time comparing different tools and techniques used in the 18th c for gunmaking.  Needless to say this was more fun than a pig in a mud puddle.  If the master gunsmith there, George Suiter, gets the tool finished, maybe the results can be posted here in the future.

Jim Everett
Title: Re: Making 18th c wood screws
Post by: James Wilson Everett on March 21, 2012, 10:57:35 AM
Guys,

Here is a scan of the screw swage tool from the mid-18th c John Wyke tool catalog.  The catalog does not tell if it for making wood screw threads of for making machine screw threads.  It appears to operate in the same manner as the original tool pictured above.

Jim
(https://i1137.photobucket.com/albums/n514/JamesEverett/Tools/Wyke/wyketool2a.jpg)
Title: Re: Making 18th c wood screws
Post by: Hungry Horse on May 26, 2012, 06:08:48 PM
Years ago I had a friend that bought a bunch of blacksmithing equipment from the old cable car barns in San Francisco. I believe that much of that equipment pre-dated the cable cars in San Francisco by many years, and may have arrived just after the gold rush. One of the things in that bunch of equipment was a hot swedge for forming wood screws, along with a scissor type finishing die that cleaned up the threads, and removed the extra flash from the threads. Most of these screws were large, and would be what we call a lag screw today. There was also a plate to make smaller wood screws out of the square headed lag blanks.
  We speculated that the original maker possibly hand made hardened steel screws, and then sandwiched them between the red hot block faces ,and hammered them until they were flush. My friend is long gone, and his equipment was spread to the four winds. I have often regretted not buying his smithing equipment. I'm sure some of that stuff was old and rare.

                                 Hungry Horse
Title: Re: Making 18th c wood screws
Post by: Artificer on June 28, 2012, 11:39:28 AM
Jim,

Just wanted to say how I THOROUGHLY enjoyed this tutorial and especially the photo’s of your 18th and 19th century thread forming tools. 

I also appreciated the photo’s of the 18th century wood forming taps as they are so similar to ones I have seen in Wyke’s Catalogue, but have never gotten that close a look at real ones before.  I have been kicking around the idea of making a screw plate and taps that fit reproduction muskets to use in my Artificer’s Kit and those photo’s will be most helpful to make the taps look correct - even as they will be in non authentic cut thread sizes and thread form.

Gus
Title: Re: Making 18th c wood screws
Post by: James Wilson Everett on June 28, 2012, 01:40:48 PM
Gus,

Your artificers kit must be really great.  Check out the topic "18th c screw plate use" to see how the machine screws were made.

http://americanlongrifles.org/forum/index.php?topic=19172.msg180948#msg180948

Like you, I often do field repairs to the reenactor guns when at show-n-tells.  I have made an 18th c looking screw plate that has the modern threads in it specifically for "shade tree" lock work.  It includes the most often used metric and UNC/UNF threads.  Folks are much suprised when I am able to make a replacement for a broken lock screw on the spot without electricity or modern tooling.    To go along with this screw plate I bring along modern taps to fit each hole in the screw plate.  What are you doing awake at 4:39 AM?

Jim
Title: Re: Making 18th c wood screws
Post by: Clark Badgett on June 29, 2012, 02:19:58 AM
Mr. Everett, would you happen to have a picture of the tap you used to form the die you made?
Title: Re: Making 18th c wood screws
Post by: Artificer on June 29, 2012, 03:56:50 AM
From your other thread:

Here is a photo of a typical screw plate that would have been used by our 18th c gunsmith.  It makes 10 different sizes of machine screws and taps. You can see the paired holes, the lower holes make a thread that is identical to the upper holes but is a few thousanth of an inch larger.  The larger holes make the tap, the smaller holes make the screw.
Jim Everett

Iim, can you hear me banging me head against the desk and saying over and over, "Gus, why in the HECK did you not think about that before...??!!" (leaving out nastier self recriminations, of course, on a family forum.  Grin.)  Well, it is quite obvious I think too much like a machinist and not like a blacksmith as I have never had an oppronity to learn that trade at all.

I was fortunate to almost trip over an original Screw Plate when we visited the National Agricultural Centre, Stoneleigh (near Coventry) in England on our trip there representing the US to the International Muzzle Loading Committee’s World Championship in 1996.   If anyone has heard of “The Big E” Country Fair in New England, U.S., this faire is two to three times larger.   In one of the two large corrugated steel covered “Baker Buildings” where antiques dealers were set up, I was picking my way through the piles and my big foot bumped into a 19th straight sided crock that held a bunch of antique kitchen gadgets.  However, by bumping the crock, a flash of metal revealed the Screw Plate.  I almost fell down diving for it and looked at the price tag not knowing how much they would ask.  The Tag was marked “Antique Drill Index” 7 L 50p or about $ 13.00.  Yes, I tried to get it down to 5 L, but failing that, got it for 7 L.  Also found a couple other tools, but not nearly as neat or as cheap.  My Screw Plate may be early 19th century, but will pass for 18th.

I never knew what the “double” holes were for and thanks for the illumination.

Gus
Title: Re: Making 18th c wood screws
Post by: Artificer on June 29, 2012, 02:15:40 PM
Jim,

My Artificer's kit is still very much in a "work in progress" stage to replace modern tools with "period correct" ones.  The idea sort of grew from when I bought and filed original 19th century screwdrivers to fit the most common sizes of musket screws when I worked NSSA guns in the 70’s and 80’s and before Brownell’s had their Magna Tip screwdriver kits on the market.   When I “came back” to 18th century reenacting in the mid 90’s, I started accumulating period correct tools to work on flint muskets and so I could do it in camp and in front of tourists/visitors – rather than hiding in my tent or car and working with modern tools.   It also came from a slightly embarrassing moment at a Colonial Williamsburg special event, “Under the Red Coat” when a buddy and I fell in with another Highland Unit because our Unit based more in Northern Virginia and Maryland, had decided not to come as a unit.

I had been informed that they wanted us “in full kit” and in formation at 8:00 AM Saturday morning , SHARP for Drill practice and inspection. Since I know SO many time periods of drill, I sometimes get a bit confused, so I wanted to be there for “Recruit Drill” to make sure I was sharp in the time period and especially as a guest with their unit.  So at 0750, I am in full kit and all by myself in formation.  Over the next ½ hour or so, heads began to pop out of tents and of course they noticed me and began to fall in to formation.  With 26 years in the Corps, I know how to stand inspection and have my gear in good order.  However, I had put a new flint in my lock the night before and had not quite tightened it down enough.  The Corporal pushed very hard on the side of the flint and it came loose.  I was SO embarrassed at such a “Newbie” mistake.  When he is chewing me out about it, he asked if I had a “Y” musket tool to tighten it and I told him I had left it in my tent.  So he handed me his.  Many of our repro muskets have holes in top jaw screw that are not period correct, but it is handy to push a pin punch in them to tighten the screw.  When I began to use the punch end of his “Y” tool, he snapped something about possibly breaking it off because it was a repro.  OK, so I tried to use the turnscrew tip, but it was too big for the slot in my screw.  I then asked permission to be excused from formation to retrieve my tool and was grudgingly given permission. 

So I ran to my tent, grabbed it and ran back to formation.  Then I began to tighten the screw with the punch tip on my Y tool and the Corporal once again growled a warning about breaking it off.  I ignored it and tightened the screw.  Then I told him I had reworked my repro Y tool to fit the musket and had hardened and annealed the punch end, so there was no way it would break off.  I also said I had modified the Turn Screw end the same way, so it actually fit the top jaw and cock screw slots.  I wasn’t trying to be a smart aleck, but he took me that way.  However, as he found some more loose screws and other things wrong with other locks, he actually had to come back and borrow my Y tool because his didn’t fit any lock but his own and I later noticed he had really buggered up the screw slots on his lock. 

Oh, I don’t want to make much of this because I’m not looking for sympathy and many of my comrades have come back a lot worse or did not come back at all.  I tore rib cartillage on both sides of my rib cage, blew out my right leg and contracted some kind of African Malaria or disease when I served in Somalia besides other things on Active Duty. (Fortunately it is not communicable.)  The last couple weeks I have had another “episode” left over from what I contracted in Somalia.  So there are times I can not sleep at night and look over the forums and maybe write a reply.  That’s why my earlier reply was posted so early. 
Gus
Title: Re: Making 18th c wood screws
Post by: James Wilson Everett on July 14, 2012, 04:04:15 PM
This is a belated reply to Clark B.

I think the tap you are referring to is the tap I made to form the wood screw dies for my "production" wood screw swage tool.  Let me know if this is not correct.  The tap was turned on a lathe and cut to a wood screw thread form.  The finished wood screws from the "production" do not look as nice as the ones made from the original tool, but they do function well.

Jim

(https://i1137.photobucket.com/albums/n514/JamesEverett/Tools/Taps/100_58271a.jpg)
Title: Re: Making 18th c wood screws
Post by: Eric Smith on July 22, 2012, 12:19:47 AM
http://www.ebay.com/itm/370631419522?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
Here is a link to those of you who might like to purchace similar tools. Act fast!
Title: Re: Making 18th c wood screws
Post by: Sawatis on August 01, 2012, 02:24:36 AM
hey Jim
Want to say what a phenomenal post this is...learned more in the 3-4 times I read this in the last night than in years just pondering! Did have a question : on your original screw swage...approximately how thick is the die plate region and on a similar note what are the common sizes (diameters, threads per inch)of 18th Century woodscrews made by the various die holes. 
John
Title: Re: Making 18th c wood screws
Post by: James Wilson Everett on August 01, 2012, 06:38:09 PM
John,

Thanks for your interest in the screw swage, your comments are much appreciated.

For the original tool:
The thickness of the plate at the swage holes is 0.203

Bear in mind that the tool is used to make tapered threads so the diameters can vary very much.
Hole #1 - 0.23 - 10
Hole #2 - 0.20 - 14
Hole #3 - 0.17 - 16
Hole #4 - 0.14 - 18
Hole #5 - 0.11 - 24
Hole #6 - 0.10 - 28
Hole #7 - 0.09 - 32

For my shop working tool:

Plate thickness 0.250
screw 0.24 - 12

Jim
Title: Re: Making 18th c wood screws
Post by: Sawatis on August 07, 2012, 04:55:21 AM
Fantastic! Thanks Jim
 That puts it in size perspective or me. I've got a hankering to fire up the ogre and try to re-create something like this! (if it wasn't 106 outside I might be more enthused!). So are the threaded holes tapered as well?  The tap you showed for your 19C tool dies appears to be parallel?  I would imagine that a die for round bottomed threads old be V cut and then dressed round with round files?  Or doesn't that really matter when swaging the screw blank in the die?  That's the ting about this pursuit...always more questions!
Look forward to any opinions and insight
John
Title: Re: Making 18th c wood screws
Post by: James Wilson Everett on August 08, 2012, 02:18:03 AM
John,

The wood screw swage die holes do not look to be tapered.  For the largest size there are only 2 threads in the swage plate, so no taper in the hole.  The tap for the "working" screw swage plate is indeed not tapered.  The early 18th c taps did not seem to be tapered or have a lead-in as we use today.  This makes them a real bear to start unless the hole to be tapped is itself tapered.  They were tapered, slightly, as they were reamed up to shape using tapered square reamers.  The wood screw tap was made on a modern lathe with a cutter ground to give the rounded thread valley as you see.  I actually tapped the hole in the new plate from which I made the "working" screw swage with the plate in the lathe head stock and the tap held in the tail stock in a jacobs chuck.  Later I cut the flats to allow turning it with a wrench and I now use the same tap to cut threads in the wood prior to installing the tapered screw made from the "working" tool.  Does this make sense?

Jim
Title: Re: Making 18th c wood screws
Post by: Sawatis on August 12, 2012, 09:30:10 PM
Perfectly Jim!  I had thought that the reaming of the hole (either in the wood or in the swage plate) would produce the very slightest taper we see on these screws and the screw then is fairly parallel sided since this how the blanks are prepared. Gonna have to play in the forge once it cools down and forge a swage up..I like ours with the spring end...easier and faster to do than the leafed hinge on the one in Wyke's
Thanks a bunch and I'll post my trials and tribulations here once it falls back to reasonable working weather here!
John
Title: Re: Making 18th c wood screws
Post by: James Wilson Everett on October 08, 2012, 03:33:05 PM
Guys,

A patent for the parallel sided and pointed wood screw was issued in 1847, patent number 4,704.

http://patimg1.uspto.gov/.piw?idkey=NONE&docid=0004704

http://www.datamp.org/patents/advance.php?pn=4704&id=25493&set=312
Title: Re: Making 18th c wood screws
Post by: James Wilson Everett on May 08, 2013, 03:42:30 AM
Guys,
Here is how the wood screws appear just before installation on the gun.  The three sizes are for the butt plate (big), trigger guard rear or toe plate (medium), and wood patch box spring (small).  In the above tutorial when I say that the screw is not cut from the rod until installation, I did not mean that the gun looks like a startled octopus, but that a short rod section is left on with a screw slot cut so if the screw slot is damaged on installation it is not a problem as the final shaping of the screw head and final slot are cut after final installation.

(https://i1137.photobucket.com/albums/n514/JamesEverett/100_5974a_zps0dd0a922.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/100_5974a_zps0dd0a922.jpg.html)

Here is a view of the butt plate and screws final installed and ready for the head shaping and final slot cut.

(https://i1137.photobucket.com/albums/n514/JamesEverett/100_5972a_zpsf331099e.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/100_5972a_zpsf331099e.jpg.html)

Here is a similar view of the rear trigger guard screw.

(https://i1137.photobucket.com/albums/n514/JamesEverett/100_5971a_zps4461dde9.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/100_5971a_zps4461dde9.jpg.html)

Here are views of the screws in their respective swage holes in the 18th c screw swage tool.

(https://i1137.photobucket.com/albums/n514/JamesEverett/100_5976a_zpse58478b2.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/100_5976a_zpse58478b2.jpg.html)

(https://i1137.photobucket.com/albums/n514/JamesEverett/100_5975a_zps0e4496e5.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/100_5975a_zps0e4496e5.jpg.html)

The big butt plate screws were made from refined wrought iron, the smaller screws for the trigger guard/toe plate and for the wood patch box spring were made from leaded steel rod 12L14.  (Metal patch box lids are just a passing fad).

At the final shaping the screw heads can be made flat or domed and the slots can be cut to align as you wish.  Notice how really smooth the threads are when swaged with the original tool, not very much roughness at all.

Jim
Title: Re: Making 18th c wood screws
Post by: smylee grouch on May 08, 2013, 05:04:44 AM
James, the counter sink portion of those screws looks to be more shallow than what I am acustomed to, what degree of counter sink do you use for those?
Title: Re: Making 18th c wood screws
Post by: James Wilson Everett on May 08, 2013, 02:10:48 PM
Guys,

Good question about the angle of the countersink.  To answer it directly, I don't know.  I suppose that I use the LAR principle - Looks About Right.  Thinking back, I can't even remember what bits I used for the countersinks, but I do know that they were standard 18th c fishtail bits and that I used more than one for the differing sizes.  The final diameter of the counter sink head on the screws is a lot less that you see in the photos.  When filing off the head for the final fit - perhaps a third of the initial head diameter goes away as the head is fit into the hole.  This seems backwards a bit to the modern practice.  Once the threaded portion of the screw is installed and the countersink is cut until it LAR, then the head is finished to fit the existing countersink.  Sometimes with original screws used in this fashion of holding a metal part to a wood base, the countersink flair is rather small when compared to a modern made wood screw.  Here are typical 18th c fishtail bits, like those I used to cut the countersinks, but not the exact ones.

(https://i1137.photobucket.com/albums/n514/JamesEverett/Tools/drills/100_4791a.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Tools/drills/100_4791a.jpg.html)

Here is what the cutting end looks like and the resulting angle of the countersink, for this particular bit.  Each individual bit will give a slightly different angle, but I have never found that it matters.

(https://i1137.photobucket.com/albums/n514/JamesEverett/Tools/drills/100_4793a.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/Tools/drills/100_4793a.jpg.html)

I hope that this explanation makes sense, even if it did not give a direct answer to the question.

Jim

Title: Re: Making 18th c wood screws
Post by: James Wilson Everett on May 08, 2013, 02:21:25 PM
Guys,

Here is a set of screw sizes for a gun that was made long ago.  Here we can see the finished heads, which I decided to make domed.  Notice how rather small the remaining countersink is when compared to a modern screw.  This is more how original screws appear when removed from the gun.  Sometimes the countersink flare is big and sometimes it is small.  There certainly was no standardization at the time.

(https://i1137.photobucket.com/albums/n514/JamesEverett/100_4656a.jpg) (http://s1137.photobucket.com/user/JamesEverett/media/100_4656a.jpg.html)

Jim
Title: Re: Making 18th c wood screws
Post by: vanu on June 21, 2018, 02:29:40 AM
I know this is a 5 yr old post, but just for grins i'm adding a comment.

Back in the early 80's i started doing some apprentice work for Wallace Gusler, one of the first things he had me do was hand file wood screws for a patch-box, seems difficult, but it taught real hand eye coordination (in slow motion).  Often I'll remind him of those days and he just laughs..."I was trying to get rid of you, but you just came back for more!" Anyway, point is; its not as difficult as one would think, the hardest part was getting the slot to center and get a crown that looked 1760-70 American. After a year of this, Gary Brumfield said he'd be happy to loan me a screw swage...my response was "a-WHAT?"  Wallace's only response was: you're moving on to draw filing tapered and flared barrels...35 years later, I'm still draw filing/polishing  tapered and flared barrels! Sounds odd, but i really like doing all this work on hand forged rod stock with no power tools involved at all, rather cathartic in a way.

Bruce
Title: Re: Making 18th c wood screws
Post by: CARROLLCO on June 21, 2018, 08:50:18 PM
Great post! So knowledgeable on so many subjects. And always so willing to share. Thank you so much James Wilson Everett.
Title: Re: Making 18th c wood screws
Post by: grizg on January 11, 2019, 02:23:03 AM
I'm new to this forum but thought folks might be interested to see some screws I hand filed. Dave Wagner got me going on doing this... then I figured out how to refine the process so I got more consistent.

(https://i.ibb.co/KxH0J8B/image.png) (https://imgbb.com/)

I'd also like to comment that the thick heads shown by James Wilson Everett allow you to clock the screws. That is, once the screw is tightened with the temporary slot the position of the permanent slot can be marked and cut.  I didn't see that mentioned.