Newbie Project. Oscillation Overthruster

[docatomic]

I'm new to building replica props and decided to take on an oscillation overthruster. The intent is to mill the final version out of aluminum. In the mean time, I have been experimenting with design and fabrication techniques using wood. The goal is to make a replica that can be customized with switches, lights and anything else an owner may prefer in order to replicate the particular model they prefer (e.g., the BB theatrical version, Star Trek versions, etc.). So far, this is what I have come up with...

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Any suggestions for parts that could be used for the details and/or suggested modifications would be appreciated.

 

[docatomic]

Here's a bit more on the project...

A few months ago I decided to take on a small project (so I thought at the time), a scratch build of an oscillation overthruster replica using aluminum as the primary material. In planning out the project I had several objectives. The primary objective was to be as true to the theatrical version as possible. However, the were several other factors that could (and would) cause a deviation from this primary objective. First of all, I wanted to build a version that could be outfitted with switches, lights and possibly some other electrical components. To me, this meant that it had to have cavities large enough to accommodate these components and any associated power source and wires. Second, since the final build would be out aluminum, I desired a modular approach that could be assembled using fasteners instead of a nearly monolithic approach that would require 'hogging' out a chunk of aluminum. I figured that by using a modular approach the model could be retrofitted with modified components at a lated date as I saw fit. The other advantage, at least for me, was that if I ruined a piece of the project I would only have to re-fabricate the ruined piece. With all this in mind, I set out to build a prototype out of wood so I could experiment with different design concepts and fabrication techniques. One of my first steps was to set the physical scale of the replica by identifying some commercially available electronic components that I could use. In particular, I tried to find the smallest switches I could that resembled what I believe to be switches on the theatrical version. This included the switches on the three 'switch plates' and the switch (or light?) on the 'orb.' What I came up with is shown in the photo below. I plan to use the switch on the far left for the switch plates and one of the other two on the orb.

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After several false starts using balsa and bass wood I came up with a design that I decided to make out of walnut. This was truly a scratch build with the raw materials shown below.

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The design called for the components shown in the next image.

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After assembly, the result is a replica that had the desired 'cavities'

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and was of an appropriate scale.

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Next step... the details and then an aluminum version. If anyone is interested I could share more details in subsequent posts in this thread.

 

[Cameron]

Please do.. Great build.

 

[docatomic]

The build-up…

First, I'll start out with what I call the 'thumb sub-assembly.' It consists of the thumb piece and the thumb plate. At the bottom of the thumb piece, two holes are drilled and tapped for 6-32 machine screws to attach the thumb plate. (Unless otherwise noted, all fasteners are 6-32.) A single hole is drilled through and tapped on the rear side of the thumb piece to attach the rear part of the top and bottom cover plate assemblies. A notch on the front of the thumb piece supports the ‘rear switch plate.’ The thumb plate has two other holes that will be used to fasten the thumb plate to the ‘orb sub-assembly’ and to the ‘knuckle.’ The thumb sub-assembly is shown below. The second hole on the side of the thumb piece was an experiment that was abandoned.



At the front of the device are the ‘nose piece sub-assembly’, ‘face plate’ and ‘knuckle.’ The nose piece sub-assembly consists of the ‘nose piece’ and the ‘front switch plate.’ The tenon on the nose piece is drilled and tapped to secure the front switch plate. The faceplate ‘floats’ between the notches on the nose piece and knuckle. The nose piece and knuckle are also drilled and tapped to attach the top and bottom cover plates.



The ‘bridge sub-assembly’ consists of the bridge piece and the rear switch plate. The front ‘tongue’ on the bridge piece supports the front switch plate and is drilled and tapped to attach the top and bottom cover plates.



The sub-assemblies described above form the majority of the bezel.



Now onto the ‘orb sub-assembly.’ The orb was made from two solid wood hemispheres. The ‘orb riser’ is attached to the front of the orb and supports the ‘top switch plate.’



The notch in the orb riser accepts the knuckle with a machine screw that passes through the thumb plate and the orb riser.



The full bezel assembly is shown below.



The top cover plate has two parts, a cover plate and a piece that I have yet to name. In the aluminum version the front of this unnamed piece will be grooved to produce the ‘comb/heat-sink’ effect seen in the theatrical version. In this sub-assembly I used a 4-40 machine screw.



The bottom cover plate has three parts, a cover plate and two other pieces that I have yet to name. As with the top cover plate, 4-40 machine screws were used to attach the unnamed pieces. The rounded piece will be grooved in the aluminum version.



The next two photos show the fully assembled prototype.



I’ll be modifying the switch plates soon to accept the switches and ‘light-posts.’

 

[nick daring]

This is beautiful looking. Its a shame that the wood isn't the final product.

 

[docatomic]

Thanks. A metal version is on the way. I am enjoying the build. I'll keep posting the progress.

 

[nick daring]

What are you using to get such precise cut on such small wood pieces? Clean work!

Nick

 

[Mr Webber]

Thats fantastic, great project.

When i first saw it i thought it was a steampunk overthruster build, would be as cool, have you thought about playing around with that when all the works done?

 

[docatomic]

The majority of the precision cuts were made with a Proxxon FKS/E precision table saw. I've had it for many years and have used it on several projects.



So, I have a bit of experience using it. But, I must admit, I have a rather large pile of overthruster parts that failed to satisfy 'form and fit' criteria. The riverboat is not complete yet. I took a break from building to work on the overthruster project.

I did a little search on steampunk overthrusters. I may consider it. I've got to finish the riverboat at some point.

 

[nick daring]

Any news on this gorgeous build?

 

[docatomic]

The 'light-posts' were made using .22 LR casings, 5mm flat-top white LEDs and #12 brass washers. There were two options for the brass washers, finishing (on the left of the figure) and flat (on the right).

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Looking at screen captures it seems (to me anyway) that the flat washers are more consistent with the theatrical version so, I proceeded down that line.

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The washers were positioned at an 'appropriate' position on the casing and brazed in place using Vulcan 65-PSS silver solder paste. A small collar at the base of the LEDs was carefully filed down so that there was a snug fit inside the casing. The LEDs were held into place using a small drop of silicon. This also serves to insulate the leads from the casing.

View attachment 101869

Next step, the switch plate assemblies.

 

[docatomic]

The switch plate assemblies contain the switch plates, 'light-posts' and mini-switches. The mounting points for the 'light-posts' were countersunk using a 1/2" end mill (a 1/2" Forstner Bit works well on wood). This allows the base of the 'light-post' to be inlayed into the switch plate. The particular mini-switches I found required a 6.2 mm hole and an M7x0.75 tap. Note that the button on the switch has a flat top. I have been experimenting with a product called 'Plasti Dip' that shows promise for giving the button a more rounded look consistent with the theatrical version. The smaller hole on the switch plate is for attaching it to the overthruster with a machine screw.



The picture below shows the upper and lower switch plates attached to the overthruster.



Next, I'll be modifying the 'orb assembly' to accept its electrical components.

 

[nick daring]

Exemplary work!

Nick

 

[Cameron]

Awesome!

 

[docatomic]

It's been a long time since my last post but, I haven't given up on the aluminum version of the overthruster replica. Based on the wooden prototype I discovered that I could scale down the size about 10-15%. The overall dimensions for the aluminum build are ~3.25" x 2.5" x 2.0". The scaling down also required some design changes. I'll get into more detail on the new design in future posts but, first, I'll show the progress to date.

 

[nick daring]

Beautiful work!!

 

[docatomic]

The build begins with the 'orb.' Its size, along with the thickness of the 'bezel' will set the scale of the overthruster. Based on what I learned from the prototype, I chose a 2" diameter solid aluminum sphere as the foundation of the orb and a 3/4" bezel thickness.



Since I will be machining the parts, I had to be a little more diligent in developing some schematics. The schematic for the orb is shown below. It's not detailed enough to be a honest-to-goodness engineering drawing but, it suited my purpose.



The next image shows the rough milled orb. In doing the rough cuts with a band saw, the scrap was saved because it can be used in other parts of the overthruster.



After more machining and drilling the final orb is shown below.

 

[lharles]

Oh, dear heavens, I love what you're doing. Thank you for including your schematic, too.

 

[Cameron]

Loving this!

 

[docatomic]

The cover plates define the overall shape of the overthruster. Unlike the wooden prototype, the top and bottom cover plates for the aluminum build are identical in size and shape. The only difference is in the hole pattern for fastening to the bezel and to other parts (the upper 'intake' and the bottom 'chevron'). Referring to the schematic, the rear portion of the cover plates are based on a 30-60-90 triangle. The removed portions are also 30-60-90 triangles. The forward portion is based on a 45-45-90 triangle with a similar, smaller, triangle remover from the nose.



The picture below shows partially completed cover plates. The top cover plate currently has three holes for fastening to the bezel. The holes are sized for 2-56 machine screws. Additional holes will be added later, after a casting mold is made for the top cover plate and upper 'intake.' Also, the plan is to put in an internal speaker (the kind found in musical greeting cards) that will produce the characteristic sound of the overthruster. To accommodate the speaker an appropriately sized hole will be added underneath the fins of the intake. The bottom cover plate currently has two holes. The reason for the 'missing' hole is that it would interfere with the layout of the bottom 'chevron.' So, in order to give the bezel some strength, the 'bridge' and 'nose' pieces of the bezel will be fastened together underneath the cover plate. I'll show how this was done in a future post.