Thanks, The Jason. It's what we're here for after all: to share ideas and findings so we can all of us help each other build replicas of our favorite show's props (maybe even favorite props).

Dino.

Whilst working on my http://tardisbuilders.com/index.php?topic=9018 and poring over the screencaps in this thread, I noticed that the 3 legs on each generator are all slightly different.

I was able to identify 3 variants as shown below:

Variant 1	Variant 2	Variant 3

Variant number 1: The narrower "chunk" is not flush with the back of the leg and also sits 1 or 2 millimetres below where the wires attach.

Variant number 2: There is a raised section on both sides of the leg and no "chunk".

Variant number 3: The narrower "chunk" appears to be taller than the rest of the leg.


If anything, this supports the theory that the original legs were found items rather than scratch-built. After all, why would the prop builders go to the trouble of designing 3 different legs when they could simply make each one identical?

I hope some of this makes sense and is helpful.

-- 14th

They remind me of ink cartridges for printers, but are probably a bit too small to be those.

Quote from: meantimebob on Sep 10, 2018, 05:22 am
They remind me of ink cartridges for printers, but are probably a bit too small to be those.

That was the theory further given up-thread, and it would make sense given that the art department were likely to have used up a lot of ink cartridges and would therefore have had plenty on hand to build the chronodyne generators. (Printer cartridges can differ slightly depending on the model, so that would explain the subtle differences between the design of the "legs" on the props.)

Number 2 definitely looks like a printer cartridge to me. I've seen that sort before. I think one of my old printers that died years ago used very similar cartridges. (Like with all of the other thingies I've tossed that I've seen lookalikes in 'Doctor Who', on consoles and various props: "If only I'd known what was going to happen in the future, I wouldn't have tossed that thing out." )

Number 3 almost looks like a printer cartridge that still has its packaging case around it - that thing you have to wrestle loose from the cartridge before you can insert it into the printer. (I guess those cartridge covers I tossed would also have come in handy now. again.)

Number 1... could be a printer cartridge, but not one I've seen before. That said, there are dozens of different printer cartridge models out there, so this could very well be another of those different ones.

So my money is on printer cartridges, maybe some with the protective cover still on them. (I'm sure the BBC props people never toss anything, just in case.) Spent cartridges that were gutted (and rinsed out) so they could get the LEDs into them.

Nicely spotted, 14th!

Dino.

Going with the printer cartridge idea, these are the only ones I could find that look similar...https://ae01.alicdn.com/kf/HTB1BoQ2jMfH8KJjy1zcq6ATzpXae/Ink-Cartridge-Remanufactured-For-Canon-PG-540-PG-540XL-PG-540-540XL-PG540-PG540XL-CL-541.jpg_640x640.jpg

Thing is, I'm not too sure how they'd match in size to the main body, I reckon they'd be too big

BioDoctor900

Quote from: BioDoctor900 on Sep 11, 2018, 11:49 pm
Going with the printer cartridge idea, these are the only ones I could find that look similar...

Thing is, I'm not too sure how they'd match in size to the main body, I reckon they'd be too big

Inkjet printer cartridges are still a possibility. Sizewise, going by the main body of the chronodyne genny (which really does look like it was made from the top part of a drinks can), there are dozens of cartridge designs out there that could easily fit a genny body the size of a drinks can. (Just use Google Images to search for inkjet printer cartridges; you'll be floored by the sheer numbers of different sizes and designs of them!)

So going by the differences in the design of the legs (three so far that 14th has noticed), it's very likely the props department just used some spent cartridges that were lying about. It's like 14th said; why would they go through all the trouble of making (at least three) different shapes for the legs?

It would have been far easier for them to just stamp out (metaphorically speaking) one shape using a plug and vac-forming the legs, especially for a prop that was never shown in close-up for more than a second or two, and never two at a time close enough together, long enough, to see the differences in design of the legs? So I'm also in the camp of spent printer cartridges for the legs. The trouble is in ID-ing the model of cartridge(s) used. (We know there were at least three different ones used, but I used "cartridge(s)" as even making a positive ID on one model would be enough. A positive ID on two models would be great. Putting and ID on all three models would be fantastic, and a serious stroke of luck.)

Dino.

While rewatching The Caretaker I took the liberty of grabbing a couple more screenshots of the Chronodyne Generators.

The first is of one of the generators that was attached to a chair in the school's auditorium and gives a clear, almost head-on view of the prop (this is useful for working out the alignment of the three different legs and the wires on top. It also shows the coiled wire attaching to some sort of plastic(?) loom on the side of the generator - on some of the other photos in this thread, however, there is no visible loom and the coiled wire just appears to have been glued into place, indicating that there were minor differences between some of the props.


The next two photos are very low quality, I know, but they were the only shots I could get of the base of the generators - which appear appear to have been painted black. At first I thought that this may have been shadow, but the colour doesn't change even as the Doctor is waving the generator around - and the screenshot on the right shows that part of the side of the generator was painted black as well. Perhaps the props had a removable base to allow access to the electronics inside, for changing the batteries, etc?

I also noticed a small silver circle in the centre of the base which looks like it could be a magnet for attaching the props to metal surfaces (depending on how strong the magnets were, they may have been able to attach to the metal frames of the chairs through the plastic seats.)

I think you've got some good ideas here, 14th. First, I think the differences in the appearance of the props could indicate they had "hero" props for the close-ups (like the one on the back of the chair that you've posted above), and then a handful of "stunt" props for long shots, and for being tossed, slid, and generally knocked about. They all could have had LEDs inside, but they wouldn't have all needed "hero" quality details.

The black bottom was a good catch! I've sharpened and lightened your images to help show the detail a bit more:


First the back. Either the splotches in the black are artefacts in the image, or this is one of the "stunt" props and has seen some sliding around or rough handling. (There also looks like there may be two screws holding the bottom to the main body. One is just above the Doctor's thumb; the other is at an almost 45-degree angle from it on the other side of the center silver disc.) This also shows up the silver disc in the center quite well, which if it's a rare-earth magnet, would have more than enough pull to hold it to just about anything made of ferrous metal (something with iron in it for those who might not be familiar with the term "ferrous"; not meaning to insult anyone's intelligence, but I have met many people my age who have never heard that term!). Even a rare-earth magnet of that size would be stronger than one realizes, and if the chairs in the scene where this thing was stuck to had a ferrous metal mesh inside the plastic or gelcoat, then the magnet would stick.


Next, the side. There is some shadowing there, as the bottom and the little "lip" extending down from the grey main body look black, but on the part facing up you can see it's more of a really dark grey, as it's not as black as the leg, which stayed black as I lightened the image. So that bottom appears to have a "tri-lobe" shape to it since the extensions of the bottom are under the bottoms of the legs. Again this would make sense for both hero and stunt props as it would allow access to the LEDs in the legs as well as the main body of each prop; one would just need to remove the bottom as a unit rather than having to remove the bottom of the main body, and the bottom of each leg.

I hope some of this babbling is helpful.

Dino.

I have earth magnets, & they work through 15mm & 20mm mdf, so would certainly work through the plastic of a chair!

Chris.

Thanks Dino, as usual that was very helpful! You make a good point on there being different hero/stunt props; the stunt props may have been vacuum-formed from one of the hero props with the major details thrown on so that they would look the part from a distance. I never noticed the tri-lobe shaped base so thank you for pointing that out (looking back at the other photos in this thread, the other generators don't appear to have a lip underneath the legs, or even a black/dark grey extension underneath - another difference between the hero and stunt props, perhaps?)

Quote from: Davros Skaro on Sep 21, 2018, 07:38 am
I have earth magnets, & they work through 15mm & 20mm mdf, so would certainly work through the plastic of a chair!

Chris.

Wow, I knew those rare-earth magnets were strong, but I never thought they were that strong!

I love that even four years after the episode aired, we're still discovering new details about these tiny little props!

Quote from: The14thDr on Sep 21, 2018, 08:01 am
Thanks Dino, as usual that was very helpful!

You're welcome, 14th. I'm glad it was helpful, as sometimes my babbling can just end up being "babbling".

Quote from: The14thDr on Sep 21, 2018, 08:01 am
You make a good point on there being different hero/stunt props; the stunt props may have been vacuum-formed from one of the hero props with the major details thrown on so that they would look the part from a distance.

I never thought of that: vac-forming stunt versions from the hero version. It does make sense to do it that way (though it still doesn't explain the three different style of legs... unless there were three hero props; I do remember that interview where one of the props people said they don't like to use any prop that doesn't have at least one - hopefully more - back-ups just in case; it's why they had kittens when Tennant insisted on using his real-life specs for his "brainy specs" as the props people couldn't find exact matches for them, and why his sunglasses in "Planet Of The Dead" had different style frames than he regular ones).

So there could have been three hero props, and the other 11 (I think we counted a total of 14 gennies on screen at once in the episode) could have been vac-formed from those.

Quote from: The14thDr on Sep 21, 2018, 08:01 am
I never noticed the tri-lobe shaped base so thank you for pointing that out

Well, I never noticed that either, until you posted your new grabs, and I lightened them to bring out more detail. Lightening images doesn't always work, but in this case it brought out a wealth of details! (So, does this mean you're going to adjust your 3D files to match?)

Quote from: The14thDr on Sep 21, 2018, 08:01 am
(looking back at the other photos in this thread, the other generators don't appear to have a lip underneath the legs, or even a black/dark grey extension underneath - another difference between the hero and stunt props, perhaps?)

That's a very strong possibility, and a good observation!

Quote from: The14thDr on Sep 21, 2018, 08:01 am

Quote from: Davros Skaro on Sep 21, 2018, 07:38 am
I have earth magnets, & they work through 15mm & 20mm mdf, so would certainly work through the plastic of a chair!

Wow, I knew those rare-earth magnets were strong, but I never thought they were that strong!

Oh, heck yeah! Even those little ones are strong enough that if you get a finger caught between two magnets on their way to meet each other, you could end up in hospital awaiting sutures! Larger ones have been known to actually crush hands to the point of amputation. SAFETY NOTE: Treat rare-earth magnets with great care. They don't have to be very close to grab hold of each other's field and slam themselves together. Search YouTube for rare earth magnets and watch some of the safety vids. Thankfully they use dummy hands and fingers rather than showing actual filmed accidents, but they do get the point across on just how dangerous these can be if you're not careful. (Always be aware of where all of your magnets are. If they're all stuck together, slide them apart; you'll never be able to pull them apart; you'll just get pinched really hard.)

Quote from: The14thDr on Sep 21, 2018, 08:01 am
I love that even four years after the episode aired, we're still discovering new details about these tiny little props!

They do have a sneaky way of hiding their little secrets, don't they?

Dino.

Quote from: galacticprobe on Sep 22, 2018, 03:34 am
I never thought of that: vac-forming stunt versions from the hero version. It does make sense to do it that way
...
So there could have been three hero props, and the other 11 (I think we counted a total of 14 gennies on screen at once in the episode) could have been vac-formed from those.

Well, vac-forming was a complete guess as it seemed like the fastest way to produce a bunch of identical "stunt" props. My other thought was that they could have been cast from a mould of one of the "heroes", but having to wait for the material (resin, perhaps?) to cure would have been more time-consuming and I thought it would require more work to make them hollow for electronics.

Quote from: galacticprobe on Sep 22, 2018, 03:34 am
Well, I never noticed that either, until you posted your new grabs, and I lightened them to bring out more detail. Lightening images doesn't always work, but in this case it brought out a wealth of details! (So, does this mean you're going to adjust your 3D files to match?)

Definitely! It's too late to change my cardboard version to include this newly-discovered detail, but I will certainly be updating my 3D model at some point. Adding the tri-lobe base will require some major reworking of the legs, however, so it may take me a few days to get this done. Purely for simplicity's sake, I won't even attempt to add the tri-lobe base to the Pepakura model

Quote from: galacticprobe on Sep 22, 2018, 03:34 am
Oh, heck yeah! Even those little ones are strong enough that if you get a finger caught between two magnets on their way to meet each other, you could end up in hospital awaiting sutures! Larger ones have been known to actually crush hands to the point of amputation. SAFETY NOTE: Treat rare-earth magnets with great care. They don't have to be very close to grab hold of each other's field and slam themselves together. Search YouTube for rare earth magnets and watch some of the safety vids. Thankfully they use dummy hands and fingers rather than showing actual filmed accidents, but they do get the point across on just how dangerous these can be if you're not careful. (Always be aware of where all of your magnets are. If they're all stuck together, slide them apart; you'll never be able to pull them apart; you'll just get pinched really hard.)

Thanks for the PSA, Dino; I only use really small magnets in my projects so thankfully I've never been on the receiving end of a serious magnet-related injury. Perhaps some (or all) of this should be added to the http://tardisbuilders.com/index.php?topic=8252.0 thread since it could apply to anybody working with magnets, not just for this particular prop?

Regards,
-- 14th

Quote from: The14thDr on Sep 22, 2018, 01:51 pm

Quote from: galacticprobe on Sep 22, 2018, 03:34 am
(So, does this mean you're going to adjust your 3D files to match?)

Definitely! ...I will certainly be updating my 3D model at some point. Adding the tri-lobe base will require some major reworking of the legs, however, so it may take me a few days to get this done.

Maybe not too much reworking. What if you just remove the bottom face from the legs? Then the tri-lobe base could serve as the bottom face of the legs. This way when the bottom is removed, the legs will be open like the main body for access to the LEDs, wiring, and such. (Possible? I can't 3D model to save various parts of my anatomy so I don't know how it all works, so I'm just guessing here.)

Quote from: The14thDr on Sep 22, 2018, 01:51 pm
Thanks for the PSA, Dino; I only use really small magnets in my projects so thankfully I've never been on the receiving end of a serious magnet-related injury. Perhaps some (or all) of this should be added to the http://tardisbuilders.com/index.php?topic=8252.0 thread since it could apply to anybody working with magnets, not just for this particular prop?

I'll definitely take a look, and if it's not already in the list, I'll add it!

EDIT: Just added this to the list of Safety Tips - Item 34.

Dino.