Making 18th c wood screws

[James Wilson Everett]

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

[Sawatis]

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

[James Wilson Everett]

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

[Sawatis]

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

[James Wilson Everett]

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

[James Wilson Everett]

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.



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



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



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





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

[smylee grouch]

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?

[James Wilson Everett]

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.



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.



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

Jim

[James Wilson Everett]

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.



Jim

[vanu]

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

[CARROLLCO]

Great post! So knowledgeable on so many subjects. And always so willing to share. Thank you so much James Wilson Everett.

[grizg]

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.



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.