Standard Barrel/Drum Bung/Plug/Adapter for S64-5 Buttress Threads (SCAD + STL)

UPDATE:  Completely replaced the DK thread library used for the NPT ports (and the prendered port objects).  The new tool is much faster, and renders are much cleaner and lighter.

UPDATE:  Changed buttress thread to have a fancy radiused blunt start; all STL files are updated accordingly.  Added pipe clamp style bungs.

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This is a bung/plug/adapter for plastic barrels/drums with the ubiquitous M64/S64 buttress threads.   (64mm major diameter, 5mm pitch, 45 degree included angle).  

Unlike all the other printable designs I found, this one actually includes the necessary flange and gasket, and uses the normal cruciform wrench instead of some reinvented socket style. The result is a plug which should be better at sealing, and it should be more resistant to getting stuck and mangled.  That's why those features exist.  It also isn't full of mesh defects.

If the wrench socket is undesired, it can be omitted.  

If you want a threaded port for a tap or pipe fitting, it can be added. Various NPT sizes are supported.

There is also functionality to add a second port (e.g. for an inlet hose or outlet siphon plus a vent port). Double ports can be sized independently,  and are automatically spaced apart as far as is allowed by minimum wall thickness.

If you want garden hose threads, install a thread adapter. Unless you like juggling an entire roll of hose, a female GHT connection should be capable of swiveling freely.  Use a GHT-NPT adapter -- a real one that won't just snap off.

Also included is functionality to add a pinch-style pipe clamp to the bung. This is mostly intended for mounting adjustable siphon tubes or for mounting barrel pumps which are too tall for the given drum height (see photo).  The pipe clamp bungs are not intended to be watertight.  Either specify a nominal SCH40 pipe size, or a custom pipe diameter. The current design assumes the use of 1/4" bolts and nuts with their heads hot-set into the respective hex pockets, but you're free to modify that to fit M6 hardware.

The TPU gasket is going to be stiffer than the typical soft flat gasket or ring.  The as-printed surface of the bung flange may be rough enough that you might consider using silicone or other adhesive between the gasket and flange.  The gasket is smaller than the threads, but can be walked down around the threads until it tucks into its groove beneath the threads.  I'm using SUNLU 90A TPU, and printing with 3 top/bottom layers and 15-20% infill seems okay.

I printed the initial test parts in PLA, 2 shells, 20% infill, with supports only on the underside of the flange. That said, 3-4 shells may make more sense for parts with ports, or if you want to risk allowing the plug to actively hold back liquid.

Prerendered STL files are included for blind and threaded parts, both with and without wrench sockets. An example assortment of double-port non-socketed bungs are also included. The gasket STL is in the directory with the blind plugs.  Pipe-clamp style bungs are provided to fit 1/2" through 1.5" SCH40/80 pipes.

I'd like this file to support S56 and S70 sizes as well, but I don't have examples, and I can find no drawings or description of the form.

The archive includes the SCAD tool used for the NPT threads, but if you want the rest of the documentation that came with it, then here it is: