G'day Chris here, and welcome back to Clickspring.
In this video I make the barrel click, and clickspring.
The purpose of the ratchet mechanism is to hold the barrel arbor stationary
after the clock has been wound.
It consists of the ratchet wheel, a shouldered screw, the barrel click, and the clickspring.
As the clock is wound, the clickspring maintains pressure on the barrel click,
and ensures that it drops into position behind each ratchet tooth that passes.
At the completion of each winding turn, the pressure is released from the winding square,
and the click locks into the base of the last tooth to pass.
This immobilises the ratchet wheel, and by connection the barrel arbor.
The energy that's been put into the spring is now stored in the mechanism,
and there's only one way for it to be released - by the barrel assembly moving forward
as the escapement ticks off the intervals of time.
The first thing I need to do is fit the ratchet wheel to the barrel arbor.
So lets get started.
The ratchet wheel teeth were cut at the same time as all of the other wheels,
and during that process it gets a hole formed in the center;
that needs to be modified into a square.
I'm using this wheel crossing jig as well as some of these custom sized pins, to mark it out.
The bench filing machine is perfect for opening up the square, using a fine, tri cut file,
and a great way to hold onto this little ratchet wheel is by using a finger plate clamping tool.
Click on the link if you'd like to see how this tool was made.
The ratchet is a good snug fit on the winding square, and Im going to use a steel clock pin
to keep it in position. Which means the next thing I need to do is mark off
the correct position for the cross hole.
I've positioned the cross hole so that the perimeter just touches the scribed line.
I used this little shop made deburring tool to take care of the small burr
thrown up by the drilling.
In classic clockmaking, tapered clock pins are a common method of fixing components into position.
The pins are about a half inch long, and have a gentle taper that locks them in place after insertion.
The appropriately sized pin is selected and then gently driven into the hole.
Although in this case I'm putting it in gently, because I have to dis-assemble the mechanism
many times before I'm finished.
OK, so with the ratchet in position, it's time to move onto the click,
which has this beautiful curved shape that I'll be forming from precision ground tool steel.
A simple paper template is a great way to mark out the part on the raw stock,
and while it was still attached, I marked out, and then drilled the center hole.
The part was then roughed out using the scroll saw,
and then taken closer to the line with the belt sander.
At this point I'm still leaving about 1/2 a mm on the work, to allow for filing.
And speaking of filing, that circular part in the center really needs to be spot on,
so off camera, I turned up a simple filing button to help me get a good result.
It fits firmly in the central bore, and I'll keep it on the part until I've completed the final shaping.
I used the filing machine to get a bit closer to the line, in preparation for the hand finishing,
with needle and escapement files.
And that's where I'm going to leave the click for now.
I'm going to hold off hardening it for the time being,
just in case I need to make some minor adjustments after fitting.
Next up is the clickspring, which was made in a similar way,
starting with marking it out on the raw stock.
There are 2 holes to be drilled. One is for the screw that holds it in position,
and the other is for a tapered steady pin to locate the clickspring precisely on the front plate.
And much like the click, I roughed out the part on the scrollsaw,
and then brought it closer to the line on the belt sander.
The rest of the profile work was done with needle and escapement files.
And at this point of the process, the tail of the clickspring was getting quite thin
and difficult to hold,
so I found it easiest to bring it to final dimension by lapping it on the india stone.
This teardrop section needs to be thinned down too,
which is another great job for the belt sander.
Some final finishing with needle files, and that's the clickspring done for the moment too.
Again I'll leave it unhardened for now, just in case I need to make any small changes after fitting.
Next I turned up the shouldered screw for the click,
as well as the small screw to fix the clickspring in place.
The process is essentially the same for each of them, and the one I'm showing you here
is the shouldered click screw,
which needs to be a snug fit inside the central hole of the click.
The positions to fix the click and clickspring were then marked onto the front plate,
in preparaton for drilling and tapping the screw holes.
So with all of the main pieces complete to the pre-finishing stage,
I can fit them to the clock frames, and have a look at how they perform together.
A light tension can be manually placed on the clickspring,
but the final position is best determined with the help of a toolmakers clamp.
With the clamp holding the clickspring in place,
the position of the steady pin hole can be marked, and then drilled.
The pin hole was taper broached,
and the steady pin temporarily inserted to confirm the operation of the ratchet mechanism.
The ratchet has a firm clean action, and everything is fitting together well,
without binding or interference.
So the parts can now be quench hardened, after coating them in powdered boric acid,
to reduce oxidation scale.
After quenching in oil, each part was tempered to blue in preparation for polishing.
I polished the screws as you've seen me do in previous videos.
For the click and clickspring I used the india stone, followed by diamantine on a tin lap,
and then gave them all a final cosmetic blue prior to assembly.
Now the clickspring is the first of several, quite long thin parts that need to be blued on this clock,
so I made a new addition to the bluing tray set to accommodate it.
Click on the link if you'd like to know more.
All of the parts were then fitted to the clock frame for final testing.
In the next video, I'll make a start on the parts that indicate the time.
Thanks for watching, I'll see you later.
And if you've just found your way into this clockmaking series, thanks for checking it out.
This is just one episode of a longer series,
where I show all of the steps to make a mechanical clock from raw metal stock.
So be sure to check out those other videos.
I also post project videos on some of the tools I need to build the clock.
And you can also find some more toolmaking info on the clickspringprojects.com website.
Thanks again for watching, I'll catch you on the next video.