So I bought some STL files… What now?

[Starfarer42]

As a Canadian, there is a special place in my heart for the Victoria/Upholder class submarine so I decided to purchase the STL files package from Nautilus Drydocks. I expected there would be some kind of README file with more information included in the download, but it’s just STL files. This is both my first submarine and my first 3D printing project so I’m a bit at a loss about what to do next.

I have a number of questions I hope someone here can answer:

1. How do I know what size of shaft I should order for the rudder/dive plane linkages? Is there a good way to measure the holes in the model? (The software I’ve got is making it hard to measure directly across the hole, as opposed to diagonally to some point deeper inside.)
2. I’d like to include some bushings to make the linkages friction-free. Do I need to edit the STL file to add the appropriate sized holder for my particular bushings?
3. The product page recommends the 70mm WTC, but should I order it with the two extra servos for the forward dive planes? I really only need one servo since I won’t be implementing any kind of retraction mechanism.
   1. If I did order the WTC with the two extra servos, would they be in the forward compartment or in the back with the other electronics?

[Ed Kirk]

I use Orca slicer to "Add Part" or "Add Negative Part" to modify the STL file. Mostly trial and error because the actual print seems to print holes smaller then actual dimensions called for. I pick a spot on the part and Add Negative part in various sizes to get just the right size, it may take several practice prints to get the size you want. Lots of work and it takes small incremental changes. I use metric parts and print in metric.

In the photo above you can see the negative part (a cylinder) shaded to get the hole size I want, in this case the hole size for brass tubing. The shaded hull section under the build plat is used as a template to locate holes for part fits between the two hull section which I bolt together rather then use glue.

I also create parts using CAD to modify STL files by adding or using negative. Orca has a measurement tool but I haven't figured it out yet.

I have been working on the Typhoon (a scaled down short version for fun sailing) for several months, I designed my own WTC in CAD and printed it.

[CC Clarke]

Every modeler's toolbox should contain a set of inexpensive digital calipers. You can order them online or buy them at any auto parts shop. I keep a pair next to my computer when modeling from a physical part and another pair at my workbench to measure parts while building. I use one, (or both) nearly every day. I also use CAD software to verify measurements during the design phase.

Usually, split hull files optimized for RC use are sequentially numbered and labeled as Top or Bottom, Upper or Lower. Print everything and lay it out. If it still seems confusing, write the part name on the interior with a Sharpie marker when you remove it from the printer. On the files I design, I label the part's ID and Rev number into each part to insure I'm holding the latest rev prior to bonding.