The Antikythera Mechanism Episode 6 - Making The Metonic Calendar Train

I agree that a 4% tin/96% copper "bronze" alloy would be totally unsuited for such an application. You can hardly even call it bronze!

Sam Robertson

Yes that enter key thing is a pest!! Re the alloys, yes I should have been clearer in my post above - Prices research is the only destructive chemical analysis that has been conducted so far. The AMRP conducted a non destructive electron microscopy study recently, with some mixed results, although overall it again suggests it was mostly unleaded low tin bronze. One interesting thing their research pointed to was the possibility of some pewter like alloys being involved - raises some interesting possibilities for ornamentation later in the build? Again though, the results appear to be severely compromised by the corrosion process. Cheers mate :)

Clickspring

... damn Return key! To finish my thought - someone (whichever archaeological group is researching the Antikythera Mechanism) probably has done this work but it is still buried in the academic literature.

Jeff Armstrong

There's a new (as in only 30 years old) technique of metal analysis using electron microscopes that is totally non-destructive. It is usually used on splinters of material because they are easier to put into the machine's vacuum chamber but I have heard of quite large artefacts being analysed this way. It cannot detect the lighter metals (Beryllium can 'seen' but not quantified) but the metals of in bronze should be easily determined as Copper, Tin and Lead are all heavy enough to give reliable results.

Jeff Armstrong

Thank you Ben, that's very kind of you :) I agree it was handled poorly - First I heard of it was the email sent out yesterday, no prior consultation with creators as far as I am aware. Had I been asked, I would have said don't fix what aint broke...

Clickspring

Hey Chris, I think the new fees change was handled poorly. More people will drop out/cancel because there was no warning given and no way for creators to eat the difference. In reaction I have upped my paltry $3 pledge to a slightly less paltry $4. I hope it all goes well.

Yes Derek de Solla Price included the only metallurgical analysis conduucted so far in his famous research paper "Gears From The Greeks" which identified it as a low tin bronze - approx 4% Sn/96% Cu (no lead, which is unusual for the period). My own tinkering with bronze alloys over the last few months leads me to think this is almost certainly incorrect, and that the sample used for analysis was probably compromised by the corrosion byproducts. A 4% tin alloy is quite soft, and very close to pure copper in its material properties, so mechanically unsuitable. My guess is that it had to be at least 10% Tin to get the required hardness for the mechanical requirements. Most of the recovered bronzes from the period also have at least a small quantity of lead, so I would expect that to have been present also - A more modern anaysis would be great, but I think the Greek government are lot more protective of the wreckage these days so probably not likely any time soon. Cheers mate :)

Clickspring

Ha ha! That would be nice!! Terrific to have your support mate :)

Clickspring

But seriously, has there been any attempt to identify the alloy(s) used to make the Antikythera, or in similar ancient devices? I wonder how the old alloys differ from the modern brass you're using. Thanks Chris!

Sam Robertson

It's too bad you can have clones helping you. I blew through your older videos; now we have to wait a long time for new material. Oh well!

Sam Robertson

Hey Derek - Yes there are a few comments in the research re stock thickness, but nobody can really be sure - the corrosion byproducts significantly compromise the measurements, and much is simply missing, so the numbers are not much more than a best guess. I've made my own estimates based on the scans, and what I think the Maker would have decided based on the practical engineering requirements - eg for the main plate I've used 5mm - It fits the scans, and is also quite reasonable from the perspective of providing a suitable bearing depth. Its clear that the Maker selected slightly more stout stock at the start of the train, and reduced the gear thickness as the train progressed - so for example I've selected 2.7mm for B1, 3.3mm for B2, 3mm for L1, reducing to 2mm for the O, P and Q assemblies (which I based on what's left of the Saros assemblies). The pillars on B1 imply that the stock gets smaller still for the planetarium and moon phase gearing (for it all to fit vertically) so overall I'd estimate the average is around 1.5mm across the device. Cheers mate :)

Clickspring

Terrific to have you on board Tom, and thanks very much for the bloom offer, I'll keep it in mind :)

Clickspring

I was wondering if you could talk a bit about the stock thickness you are using. I think I remember seeing in one of the papers that average gear thickness was 1.2-1.4mm. It's hard to compare in the videos, but yours look more like 3mm, maybe 4mm on the thicker doubled gears? And maybe 8mm for the front/back plates? I haven't been able to find much about thickness in the papers I've been re-reading. Any insights from you would be wonderful. I'm loving this series!

Derek Meisenhelder

Just joined. I've watched all your projects to date. Glad to see # 6 in this series. I like the way your making the tools as would have been used. I'm more of a blacksmith than machinist but I'm learning. I also smelt a bit of Iron. Would be happy to send you a bit of Bloom Iron that has been forged to bar form for you to play with.

Tom Walker

Merry Christmas and all the best for the New Year to you too mate :)

Clickspring

Thanks Chris, and if I may without offending anyone Merry Christmas and a Happy and Healthy New Year

Ralph McCoy

Ha ha! Nicely done Ralph!! I'm currently recording a TGT, and I think I'll get cracking on the next BSC after that - so best estimate at the moment is that it will be out towards the end of this month. Cheers mate :)

Clickspring

Chris, Good day to you, I can only imagine the work both mental and physical plus your life in general. But when will the next part of the Byzantine Sundial-Calendar. See how I buttered you up then dropped a selfish request. Ralph

Ralph McCoy

Cheers Dan!

Clickspring

Brilliant stuff man. It's amazing hearing your insights into the mechanism as you go along. Thanks!

Dan Cowsill

Yes there are quite a few factors affecting its accuracy, but I think the main consequence of the triangular tooth profile is the backlash - its quite significant compared to cycloidal or involute gearing. Cheers mate :)

Clickspring

Awesome work as usual, I love seeing all those gears moving at once. Out of curiosity, will the triangular teeth significantly affect the accuracy of the mechanism vs. cycloidal ones? I know the AM was reputed to be not particularly accurate due to the mechanical tolerances of the time, so I wasn't sure if you were going for a complete reproduction or a modernized version. Thanks!

Erik Larsen

Hey James - Yes its largely superseded the little Panavise - so convenient to use, very quick to reposition work, brings the work right up to eye level, I love it.

Clickspring

I'm curious -- do you find yourself using (or wanting to use) the small parts vice you made for other projects?

Hey Dale, yes this is a standard HSS parting blade with the cutting end ground on an angle, with the deepest part of the cut adjacent to the work. You are correct that it will certainly turn and curl the chip which can often help when parting off. But its main bonus is that it ensures that the workpiece separates from the parent stock very cleanly right at the base of the work. Cheers :)

Clickspring

I noticed that you are using a angled cutter as a cut off tool when you cut the washers toward to end of the video. Is this just a regular cutter with an angled tip or something you ground. I don't think I have ever seen a cutter used this way. It makes sense since it would seem to be less likely to bind on a thicker cutoff.

Thank you Russell :)

Clickspring

Cheers Lucus!

Clickspring

This device is beautiful. You are a true craftsman.

Russell Reckman

I recently started making my own gears on my mini mill. These hand cut gears look amazing tho! I don't even want to know how many hours of practice you had to get in and how many blanks you had to toss in the bin before getting to this point.

Lucus Landers

This doesn't capture what I mean. This video is amazing, as are most of your productions. Your selected project, technical skill, photography, lighting, editing, narrative, and narration set a new standard for this type of content. One moment in particular stood out to me in this video. At 20:58 when you cut to correct the ill fitting gear, your shift in focus and lighting between the partial assembly to the work holder, to correcting the gear, and then back again to replace the now fitting gear was visual poetry. Can't wait for the next one.

Another great segment. Thanks Chris!

Cheers David :) The stub drills are a locally made spotting drill, mostly from this set: <a href="http://www.suttontools.com/products/spotting-drill-sets-120-d176-sets/" rel="nofollow noopener" target="_blank">http://www.suttontools.com/products/spotting-drill-sets-120-d176-sets/</a>

Clickspring

Awesome to hear that mate! I wish I could release more &amp; faster too, definitely always pushing to get better at that side of things :)

Clickspring

Terrific to have your support mate, thank you :) Yes you are spot on that the back dials of the mechanism can't be set like a modern clock, although there are a few practical ways to get around the issue - One is as follows: The mechanism can be set with the rear dial plate removed for access. A given date is set on the front dial via B1 (using the mean sun pointer as the reference), then the output pointers (in this case the N, O and Q assemblies) are aligned to the desired position before being inserted into place. Then the rear dial plate would be re-installed. Accuracy is limited to a single tooth space on the inserted gear, but in practice this doesn't amount to a meaningful error. The angular distance of a tooth space is small and well inside the resolution of each of those dials. Similar ideas apply to the Saros and Exeligmos pointers. However this setting process becomes a bit more complicated for the planetarium - I'll go into this in more detail when I get to that part of the mechanism, but it would have been quite fiddly aligning both zodiac position and the correct point in the synodic cycle at the same time - it would not surprise me at all if a section of the text on the cover plates was one day translated to say "...and if you open this thing up and mess with the gears, you'll be paying my fare across the Mediterranean to come fix it for you!"

Clickspring

Chris - Lovely, do like the depth adjustment. Interesting use of the stub drill in the plates. are these pop rivet drills or from a larger range of sizes? Cheers

David Paterson

Cheers mate :)

Clickspring

Ha ha! Terrific mate, so pleased you're enjoying them :)

Clickspring

Thank you mate!

Clickspring

holy cow, Chris, GREAT work! I so much enjoy watching your videos. Thank you for doing them! Just wish you had duplicates so you could release more! :)

Micheal Malsed

As always, this video was a work of art that required my immediate undivided attention when it hit my inbox. A question that came to mind while watching: how accurately, if at all, did the wheels need to be aligned rotationally before you filed the square holes? While a modern clock would have hands/pointers that could be adjusted on the shafts to match the face markings, AM is locked down solid. Are you going to have to do this the other way around, setting the face to match the hands? If that's the case, would I be correct in thinking that the wheels (especially the odd tooth counts) will only be allowed to be reassembled onto their square arbors in exactly one orientation?

Aaron

Great stuff Chris, as always! I couldn't help but draw parallels when you were talking about how the original builder had not gone for the straight forward option but had gone for the harder to make, sleeker design. Much like yourself, in a way, where you could have made the whole thing using modern methods but have chosen to make parts in the ways that they could/would have been made back in the day. Awesome.

Simply stunning, the project is coming along beautifully. I feel like we need to clone you Chris, as your videos are so therapeutic to watch I feel like we could extend our lives considerably just by watching a new Clickspring video every day. Yours, a relaxed and temporarily cured fidgeter.

Matt Tester

Amazing as always Chris - you’ve certainly been busy since the last Episode! Great work!

Ha ha! That would be fun! Although I suspect I will be well into production of the next project by the time I finish this one :)

Clickspring

Hey Chris - It would be nice to be able to lock in the finish on some of the parts, but unfortunately its not suitable for this machine due to almost every surface being operational, so lacquer would gum things up. I might get away with lacquering the dial plates, but I suspect it will look better to just let an authentic patina develop over the whole thing to give it a bit of character. Cheers mate :)

Clickspring

Ha ha! He's a good influence on me! My Dad jokes are improving out of sight!!

Clickspring

Cheers Paul! Yes I used the lathe to cut several of the wheels to save some time - I'll keep hand cutting the wheels that help tell various parts of the story, but I've come to realize that there is no functional difference between hand and lathe cut teeth, so it will continue to be a blend of both methods going forward.

Clickspring

Cheers jason, yes the Curta would make an excellent project :)

Clickspring

Cheers Phil :)

Clickspring

Cheers Kenneth :)

Clickspring

Good morning Chris! What a great way to start a Monday morning. I do have a question: Back in the late 70's and early 80's when I was rebuilding clock mechanisms, one of the steps that I did on the higher end pieces that were visible, was to dip the front, back, and any other large brass pieces in lacquer to keep from tarnishing. Do you have any plans to do the same?

Chris Muncy

I truly look forward to each video. You do amazing work Chris, even though you hang around with This Old Tony! :-)

Kirk Jensen

YAY a new clickspring video. Cancel everything and hit that full screen button :) Another great video. Did you cut all of the teeth by hand or use the lathe for some of them?

Paul Busby

Excellent video as always! If you are looking for ideas for your next project, may I suggest a mechanical computer of some sort along the lines of the Curta or others of it's ilk. I bet you would produce something truly elegant.

Jason Doege

Another great video - thanks Chris.

Phil Sydor

Pure viewing bliss

Kenneth M.

Cheers Aidan, so pleased you enjoyed it mate :)

Clickspring

Thank you Gordon!

Clickspring

Mate I've gotta, say, the wait for your videos is always worth it

Aidan Jeffes

Hi Chris, such a long time since your last submission on Patreon. Your latest submission is brilliant and I have watched it 3 times already. Good on yer, mate!

Gordon Burns

So pleased you're enjoying the analysis Chris - there is so much information buried in this one little machine it could easily take a lifetime to fully uncover - I promise I won't take that long tho!!

Clickspring

Thank you very much Chris :)

Clickspring

Thank you Tim! Yes I'm loving the vise, its a real knockout for working with small stuff, up at eye level. Half the time I don't even bother with the locking clamp, just the compression on the leather jaws is enough to hold many parts, so its super convenient to reposition the work.

Clickspring

Top stuff as usual Chris... it's been a while between visits to your shop so this came as a nice Monday arvo surprise once again. :) Loving the historical/educational aspects of the project, you make a good history teacher with an ability to provide insight into the ideas and processes of the mechanism's original designer/manufacturer. The revelation about this being a refined version of the design vis-a-vis pinless retention techniques was quite fascinating. You've obviously done quite a bit of reading (and thinking!) regarding these ancient mechanisms, and it shows. Keep up the great work, looking forward to the next one!

Chris Talbot

I cannot fathom how you aren't a professional. The sheer talent and skill you display in every video is incredible.

Chris Ivison

Another outstanding video Chris. That final assembly looked very satisfying! That vice also looks like just the right tool, so easy to preposition parts while working on them. :)

Tim bennett

Awesome to hear that Scott :)

Clickspring

Chris, absolutely fascinating! I just can't get enough of your videos.

Scott Clausen

Cheers Joe :)

Clickspring

Thank you Mathew, so pleased you're enjoying the vids :)

Clickspring

Simply mesmerising Chris. Always a delight watching your work.

Beautiful work as always, chris! Your work continues to astound me!

Mathew McGuire

Awesome! So pleased to hear that mate :)

Clickspring

Thank you Gregor, I very much appreciate your encouragement mate :) Re the alloy - I've tested out a few alloy combinations, and come to the conclusion that the 5% mentioned in the Price paper is probably a bit low and not correct - 5/95 is just too soft, and too close to basic copper. I think its probably closer to &gt;10% just to meet the mechanical requirements, and the sample that was used for the alloy composition test was probably compromised by the corrosion products. I doubt the Greek government will let anyone have another piece for testing, so its probably going to have to remain unknown for the time being. Cheers :)

Clickspring

As always, an excellent video, Chris. Highlight of my day when you put these up!

Adam Slagle

Ha ha! Me too!

Clickspring

Thank you mate :)

Clickspring

Here you go Ken: <a href="https://www.patreon.com/posts/antikythera-5-14429958">https://www.patreon.com/posts/antikythera-5-14429958</a> Cheers :)

Clickspring

Ha ha! Anything to get out of doing the dishes! The clock has settled down to about a 20 second per week gain - so its not in the high end timekeeping zone, but its quite a respectable result considering the simplicity of the design.

Clickspring

I cannot compliment you enough on your presentation and beauty of the work on this most interesting artifact. Have you discovered anything about the alloy(s) used in the original beyond "low tin bronze 5%Sn 95% Cu" ?

Gregor Shapiro

I was about to go to sleep, but then I'd just be tossing and turning wondering what I was missing in the video. Amazing work, as always.

Stronghold Armory

Another great video, thanks Chris, I squeeed when I saw the notification, yes I'm a 10 year old girl sometimes lol

Luke Pettit

Terrific to hear that Max :)

Clickspring

Wow Chris, you continue to amaze and inspire me! At 22:14 when you flip the mechanism on its side we see a crown gear. Did I miss you making that part?

Ken Condal

Absolutely amazing as usual, literally dropped the dishes I was doing to watch this when I got the notification. The detail/craftsmanship you put into your projects is worthy of recognition. Out of curiosity, how accurate is the time your clock (previous project) keeps? Is it close to that of a chronograph?

Tristan Sobey

Always enjoy watching your videos.

Thank you John :)

Clickspring

Ha ha! thank you mate :)

Clickspring

I wish I had a hundredth of your talent and patience.

Daniel Shattuck

Chris, I can't even..... the amount of skill, patience, talent, just wow!!! I have heard you mentioned in a few different videos over the last couple weeks, you have quite a reputation for your amazing abilities and your awesome vids.