tardis roundel reference

[Theta Sigma]

Karsten,

Can you give me a general idea of how you want the former made?  Obviously 3D printing a former that would create the central disc would be impractical.  For me, I will leave a deep void in the center to be later filled with liquid plaster after the detailed section is formed.  The liquid plaster will self-level and hopefully form the flat center. 

If you intend to use clay, you may want to take a different approach.  If you can do a rough sketch of how you want the former to look, I will mod the former to your needs.  The good news is that I have already done some test uploads into Shapeways, it it works!



Looking forward to finally laying this one to bed!

[galacticprobe]

Looking great Kevin, can't wait to get that cad file

I'll second that! (Both parts of it. )

The good news is that I have already done some test uploads into Shapeways, it it works!

Looking forward to finally laying this one to bed!

You've worked hard on this one for so long, Kev, that you've certainly earned that rest from it once you're finished!

Dino.

[Theta Sigma]

I would probably get an F in drafting class if I submitted this drawing.  In this case it was not designed to be read by a person, only by a machine.  I'm no draftsman, that's for sure.  This is a complicated shaped!

Tony/Karsten, I'd love some feedback on these drawings before I post the actual STL files for 3D printing.  I'd hate for people to go spend money on 3D printing unless we all agree on the drawing.



And here it is with just the locations for drilling, should someone wish to go that route.  You would print the drawing to a scale necessary to match the 84mm dimension.



A full roundel, roughly 4mm thick will cost around $700 to 3D-print from Shapeways.  

The formers (1mm thick) will cost $5-$7 to 3D-print from Shapeways, depending on which type.

Type 1, with hollow center designed for plaster use.  The hollow center would later be filled with plaster.



Type 2, designed for clay use, assumes that work surface will profile center section.

[tony farrell]

Well, I can follow your drawings - so, you must have done a good job. 

I entirely agree with the shape (well, I would, wouldn't I?!) but, I wonder if I could make a suggestion for the 'formers'?

Might it be an idea to include the radius of the central flat disc? By which I mean to include a central rod (akin to the Dalek dome 'former' from the 1973 Radio Times' Tenth Anniversary Special I posted a few replies ago).

That way, if someone wanted to actually make a roundel mould, they would have a 'former' which could be rotated around the 'centre-point' i.e., to actually sculpt the clay/plaster. Once the 'former' has been removed, all that would be required would be a small amount of filling for the hole left by the central rod.

Would that be feasible?

T

[Theta Sigma]

The radius of the center disc is 165mm.  These formers designs are only 1mm thick, and will require some type of support system to reinforce them before they could be used to turn plaster/clay.  Even if they were thicker, you'd still have to support it somehow because the former would be too flexible otherwise.

See my thread on my previous attempts of making a roundel for pictures of what I mean on mounting the former.  February 2014 update.

http://tardisbuilders.com/index.php?topic=1286.msg60401#msg60401

The former would be mounted to the support system in such a way as to get the required 165mm radius of the center disc.

I have now created a former drawing to encompass the entire radius of the roundel, but that has doubled the expense of 3D printing up to $13.   Still not bad, but I suspect there are better ways for forming the center disc.  I could be wrong.

Also, in my experience, trying to get a flat surface like that from a former with plaster turned out to be almost impossible.  Maybe I just don't know what I am doing when it comes to clay, but I have had zero luck with it.  

Since the former has to be mounted to a support structure anyway, I figured someone could just use any flat material to augment the former and produce the flat center.

I hope I have explained that well.

Here is what the former would look like with the full center disc included.  I now have STL file for it too.

[Theta Sigma]

STL files can be downloaded from my Google drive at the link below.  Use at your own risk.  The drawings may still yet be modified if there is further discussion on the profile.

There is also a URL shortcut included to a neat little free STL viewer program that I love.

I have ordered a V1 former from Shapeways and it should ship to me on August 17th.  I will share what it looks like when it arrives.

https://drive.google.com/drive/folders/0B9wuQYOPzaXcQjIwZGgxTG4tMm8?usp=sharing

[Rassilons Rod]

So the centre is flat? Didn't we discuss that it was convex, earlier?

*confused*

[Theta Sigma]

I thought we had come to the conclusion that the convex nature of the center disc was due to warping of the fiberglass, not intentional.  Tony?

[timewomble]

Forgive me if somebody already suggested it, but is it possible that they used a frame from a circular mirror or picture as a former, and didn't actually construct it at all?

[tony farrell]

I thought we had come to the conclusion that the convex nature of the center disc was due to warping of the fiberglass, not intentional.  Tony?

I agree Kevin (I may call you Kevin, mayn't I?    ).

I suggested that tight production schedules, the fact that perfection wouldn't be needed for 625-line transmission and the possible use of polyester resin/insufficient 'curing' time as the cause for any imperfections/unevenness in the Newbery roundels.

T

[timewomble]

Here's an example of the kind of thing I was thinking of. It's not meant to be a match, but just illustrative:



From here: http://www.remaart.cz/obrazydobytu/eshop/116-1-NABYTEK-DOPLNKY/0/5/25170-Kulate-zrcadlo-pr-52-cm

[Theta Sigma]

Forgive me if somebody already suggested it, but is it possible that they used a frame from a circular mirror or picture as a former, and didn't actually construct it at all?

I think it's highly likely that something "off the shelf" was used to make the roundels.  We will probably never know what that was.  If someone is still alive that knows, they will probably take their secret to the grave.  Even if information comes out, the chances of someone finding that exact thing from the 70's that was used is slim.

So, baring any new information, the best we can do is try to reproduce it using whatever means we have available.

[Rassilons Rod]

Oh!

Perhaps I'm just too fond of the convex middle to absorb that information

I'll probably ask again in a few weeks 

[Theta Sigma]

Well, hopefully somebody will attempt to make a plug and subsequent fiberglass copy.  I still plan to, but at my current rate it may not happen before I reach retirement age.   

We shall eventually see then if the center does indeed warp into a convex configuration.  When you think about it, it might have been desirable to avoid harsh light reflections on set.

[Theta Sigma]

I agree Kevin (I may call you Kevin, mayn't I?    ).

You may indeed! I answer to all kinds of names, some of which I can't mention here.