G'day Chris here and welcome back to Clickspring.
In this video I add the first components
to what will eventually become the main drive wheel assembly.
Now I had expected that this would just be a quick task
on the way to completing the input crown wheel assembly.
And I even went as far as preparing the raw stock for that part of the job.
But fitting B2 ended up being quite an interesting process on its own,
so I'll cover the crown wheel assembly in the next video instead.
I started by marking out the blank with 64 divisions,
using the shop made dividing plate shown in a previous video.
Next, I formed the teeth, using one of the files custom made for the purpose.
Be sure to check out that video if you haven't seen it already,
as well as the related video on case hardening.
Now before I do any more with this wheel, I'd like to show you a bit more detail on
where it fits into the mechanism.
Its permanently fastened to the main Solar Drive Wheel B1,
and its part of the gearing associated with the back half of the device.
In fact its the first wheel in that large and quite complex part of the mechanism.
It engages 2 wheels, that in turn drive the gearing
that animates the eclipse prediction display,
the calendar display
and the lunar phase display.
Now that's a lot gears, generating a lot friction.
So the load on B2 and its rivets is considerable.
And The Maker has addressed this issue in the design of the component.
Firstly by making it quite stout.
It has a relatively small diameter,
and it's one of the thickest wheels in the mechanism.
And secondly, the scans show 4 quite substantial rivets
placed in a symmetrical pattern around the spokes,
that hold B2 firmly in place.
Its a very neat solution
that wouldn't be out of place in a modern clock mechanism.
Now the central bore of B2 needs to be opened up to match the main bearing,
and it could be simply drilled out on a drill press.
But I decided to relocate the part back on the lathe to do the job.
It makes it much easier to hold, and ensures good concentricity with the teeth.
A light rub on some abrasive paper took care of the small burrs thrown up when I filed the teeth,
and that's B2 complete for now.
Next up I made the circular spacer that fits on the other side of B1.
And you'll notice that I haven't used any marking fluid to make that circle more visible.
I've done this to show just how hard it can be to see even a simple object line on bare metal.
Even up close I think you'll agree it's not exactly the clearest line you could hope for,
particularly if you were working on something really critical like, say,
filing teeth, or locating a hole.
So I think it's reasonable to assume that The Ancients would have tried to improve this situation
with some sort of equivalent to our modern marking dyes.
If they did, it would've needed to be something that was easy to apply and remove,
and hopefully robust enough to take a fair amount of handling before it wore off.
It would also have needed to provide a distinct colour contrast
to make the lines stand out to the naked eye.
Of course marking out rarely happens in isolation.
There's usually a few alignment tools required to get that scriber
exactly where it needs to be, and this job is no different.
So I've made a couple of small alignment pins to help me out.
One to locate parts on the division plate,
and one to bring all 3 components into alignment for drilling out the rivet hole positions.
Now it certainly doesn't meet the requirement of robust handling,
but a very straight forward marking material worth investigating is candle soot.
It can be applied and removed easily, and the contrast it provides is excellent.
The positions for the 4 holes are now firmly located over the centerline of each of the spokes,
and can now be drilled out in preparation for accepting the rivets.
And as tempting as it is to just drop in all 4 rivet holes at once,
even the slightest movement of the work whilst drilling can lead to an unacceptable
misalignment of the holes.
So the standard clockmaking approach is to play it safe,
and drop in a steady pin first to lock the orientation.
The hole is taper broached, and then a pin with a matching taper is tapped into place.
It gives a very precise and reliable lock, and the pin can be easily tapped out,
later in the process.
The 4 rivets were turned to size,
and left just long enough to allow them to be comfortably held for insertion.
By now of course a lot of the soot has worn off,
so I think its clear that it really wouldn't be suitable for marking out
anything that needs a lot of handling, like for example the wheels.
But despite that flaw, it did a reasonable job in this situation,
so I'll keep it in mind for some future parts.
If you can think of any other materials that might be plausible,
then be sure to let me know in the comments below.
The steady pin was removed, and the location drilled out for the last rivet.
I reduced the length of the rivets, using the belt sander.
And then started the process of permanently setting them in place.
I made sure that each rivet end was thoroughly peened,
and that the metal was pushed well out into the chamfer,
giving not just a seamless join, but also good solid mechanical strength.
And for the final step,
I used a file and 800 grit abrasive paper to blend the rivets into the surrounding metal.
The process of rivetting has pulled the parts firmly together,
creating a good join.
And that extra mass at the center has had an interesting effect
on the feel of the main drive wheel.
It now has quite a decent heft to it.
And as I reach the end of this video,
its hard to escape the thought that over 2000 years ago,
there was moment, just like this.
When this iconic assembly was given its first trial fit on the main bearing.
And The Maker, carefully assessing the work,
Watched it turn for the very first time.
Thanks for watching, I'll see you later.
Now if geared mechanisms like this are your thing
and you'd like to help me make more of these videos
then consider becoming a Clickspring Patron.
As a Patron of the channel, you get immediate access to the Patron Series of videos.
This includes the 5 videos from the Wedge Style hand Vise build,
and at present the first 4 videos of the Byzantine Sundial Calendar build
with more to come as the project progresses.
In the most recent episode, I made the small assemblies
that will one day predict eclipses in the mechanism.
And don't forget that as a Patron you also get free access to the plans
for the Patron Series projects, so you can follow along and build it yourself if you wish.
Now as an added patron reward, for a limited time,
I'm also offering $10 off your purchase of the Clickspring Fire Piston.
Its a terrific little fire starting device based on the prototype that I made some time ago.
And makes a great addition to any camping or hiking bag.
So be sure to visit Patreon.com/Clickspring to find out more.
Thanks again for watching, I'll catch you on the next video.