History of screws

 at the10.36 minute mark , shackles and even better at 13,39  from the book Loffelholz Kodex  (1505) German thumbscrew and torture devices 

Wonderful video.

Always good to have something interesting to watch during lockdown.
I'm guessing the internal thread devise had your cogs going as well when it comes to darby keys?

PaulJDavies wrote: ↑

Jun 02, 2021

Always good to have something interesting to watch during lockdown.
I'm guessing the internal thread devise had your cogs going as well when it comes to darby keys?

Yes it did. The creation of the master thread and pointed pegs to trace that thread is genius.  It reminded me of Heron of Alexandria's machines. Another genius of the ancient world.

Sorry the quality of Heron isn't good, looks like someone filmed the TV when it was on.  

Nice find on the original video! Thank you for sharing that with the board!
-Richard Knip-

A very interesting topic! As talking about bolts I come to think of the lock system in the Oregon Boot. The version with the two ended key with different threads.
As I understand these are called "trapezoidal thread". I still can't figure out how these are working, Maybe you can explain Ian?

Lars

Hi Lars, I think I made a drawing several years ago. Give me a day to search for it, the drawing should explain it clear than words. 
 In the mean time, I try this. Consider the Caveney handcuff, the mechanism only goes in one direction, the key screws onto a thread (RH) which drives the mechanism to turn. As the key screws onto the thread(RH) and tightens, because it cannot screw on further, the turning force, drives the mechanism to rotate. When the keys is turned anti clockwise (to unscrew) because the mechanism cannot go backward, it stops and the key can and will only unscrew.   
In the Oregon boot, the bolt  is a larger diameter. On one end (the end the key fits) there are two thread pitches cut into it. One goes Right hand (clockwise) the other goes Left hand (anti clockwise)  The threads cross over each other and the centre shape between thread looks a diamond pattern. The other end of the bolt is standard RH machine thread to fasten the boot. The key has an internal thread at each end. One cut RH and one LH. When the key is screwed onto the bolt until it is tight and cannot go further, the turning force is subsequently transferred to the bolt and forces it to rotate in the direction the key is turned . One will turn the bolt to screw into lock and the other to unlock. (depending on which end is being used)

Thanks Ian for the explanation! I think I can understand and see the bolt with the two threads., one in each direction.

When we get visitors and they want to see my collection, the Oregon Boot is one of the items I use to show. So far, all people are impressed
by the peculiar construction. It's really genious.

Lars

One of the Oregon Boots that I have has no threads.  It operates as a friction fit to open and close the locking device.  Works very well.

Ron

ronspitz wrote: ↑

Jun 03, 2021

One of the Oregon Boots that I have has no threads.  It operates as a friction fit to open and close the locking device.  Works very well.

Ron

Hi Ron, a kind a trusting collector once sent me a bolt form there Oregon boot of the conical design you mention. I was able to make a key for it, so if you ever lose your key ....  I would have thought that any form of rust would not allow for full contact of the key, but I assume the metal doesn't.

Lars, I am still working on the diagram but I found my notes on the design Ron has

Ian McColl wrote: ↑

Jun 04, 2021

Lars, I am still working on the diagram but I found my notes on the design Ron has

Thank you Ian, this design was totally new to me. I wonder how many different designs the OB locks came in?

Lars

Here is the original key for the boot.
Ron

Hi Ron, thanks for the photo, I never knew it had a wooden handle. It appears the rear end has hammer marks. I wonder if at anytime it has been hit to firm up the friction needed to unlock a tight bolt.