Step 3: Inserting the First Gear

This is the first rewarding step to building your roto cast machine. The first steps are to drill holes in preparation for the threaded rods. You will need to drill a series of 4 holes on the 18x18 inch 1x1 frame, and 2 holes in the 16x16 inch frame. All the holes for the 18x18 frame should be drilled in the exact centers of each side. The holes for the 14x14 frame should be drilled in the center of the top and bottom sides.

Once you have the holes drilled, you can then put the threaded rod to use. We will be putting a rod through the top (the 3.5 inch 5/16 rod) and bottom (the 4.5 inch 5/16 rod) of both frames. (refer to schematic) The rods will need to be fastened incredibly well to certain parts of the frames to allow for secure rotation. Additionally, other parts will remain loose. For the loose parts, it is still necessary to put a washer and nut on either side of the hole to ensure that the motion of the machine is not thrown terribly off swagger. I used a stop nut on the ends of the rods, and regular nuts on the inside of the rods.

After you have the rods secured, you will then need to attach the gear. To do this you will need to clamp the flat metal piece across the gear, and mount it on the gear using the two of the mounting holes. From there, you will then need to drill a 5/16 inch hole in the very center of the metal plate for the rod to go through. After that is completed, secure it to the rod with a regular nut on the inside, and a stop nut on the outside. Then place epoxy over the nuts, to ensure the gear can not become loose.

<p>I made this a couple of weeks ago, and tinkered around as I made some errors. I put another 3.0 inch flat metal plate with 4 holes in the bicycle chain ring at the top by the winder. My moving frame had some movement that caused the chain to come off.</p><p>I did get it moving smoothly but I am getting odd sections of pooling in my casts, and thin to no coverage in some spots. I wonder if I am spinning too fast? I have continued spinning past the curing time of 12 minutes, so I am certain I am not stopping too soon. </p><p>Thanks very much for the plans! </p>
<p>So, I think the issue with mine is the SmoothOn slush casting material kicks off too fast and pools in one spot, but I did get better coverage by rotating 10 turns one way, and 10 turns in the opposite direction for the duration of the cure. </p>
<p>my only question would be ; how well can i get smaller details cast this way? im starting to get into 1/4&quot; scale modelling and some of the details are pretty small .. like rivets..window trim and such..how well does this process allow them to show?</p>
<p>not sure how big your models are but if you want intricate details you might be able to pressure cast the resin.</p><p>Good instruct able here https://www.instructables.com/id/Bubble-Free-Resin-Casts-with-Modified-Paint-Tank/</p>
<p>very very clever.....i like</p>
<p>Nicely done!</p>
<p>Check out this professional version that has motor</p><p><a href="https://www.kickstarter.com/projects/rotomaak/rotomaak-desktop-rotational-casting-machine" rel="nofollow">https://www.kickstarter.com/projects/rotomaak/roto...</a></p>
Woot woot! I am now in awe of you!!!! Looking at $$$$ machines, now I am going to follow your foot steps. Thinking metal instead of wood, though. Keep rockin' it DIY style homie!
This is my first introduction to rotocasting. Can you tell us more about the process? It looks like you are just turning the mold over and over so the casting material just coats the inside. Is there more to it that that?
And that just kind nailed the whole point of rotocasting. In that it is used to make hollow positive of the mold......
It sounds like you were chewing on your vodka infused bacon while you shot the video.
I&quot;ll be updating this Instructable, as I got a lot of good feedback from Maker Faire...stay tuned <br />
waiting.... patiently... for the updates :)
Hey I was just wondering what are the sizes and weights of the molds you have put on the machine? I work with life sized heads a lot, and would like to start using some materials that require a rotational machine. Any information you could give would be a great help. Thanks. M
i found that when i made one of these that i needed one of the sprockets to have more teeth, giving the central frame more varied rotations and giving a better, more uniformally hollow cast overall. would you in retrospect make any alterations to your design?
The cast rhino head looks great, proof your instructable works! How about another on mixing & coloring resin before the pour?
Was that some Crystal Castles playing in the background the song is Crimewave im a huge fan of them
Holy Crap, its the Reider in the hizzouse!
Interesting idea having one sprocket directly driving another. How are these components wearing?
@Geordiepom Sprockets are wearing well so far. The only addition that I might make is a counterweight, as when the mechanism is turned, it has a tendency to speed up during certain parts of the revolution due to the imbalance.
@spike shadows Thanks for the concern. If you go to step 7, you can watch a video where I actually have a mold mounted in the machine. Basically, I duct taped it to the mesh on the small frame. You could strap it in using some other method, but duct tape is quick and easy.
can you show where to mount the molds? I can't really see it anywhere in here

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Bio: Just a SF local tinkerer, entrepreneur, and artist.
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