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Just in case anyone thought I forgot about this build ... nope.
![[Image: 20220725_152451-small.jpg]](http://www.niflheim.net/droidbuilding/images/four-nines/20220725_152451-small.jpg)
I've been focusing on LD-F1 for awhile now, and I'm currently fiddling around with component placements so I can finish up the chassis design. But this droid is still floating around in the back of my head (so to speak).
There's a very high likelihood that Four-Nines will end up temporarily static (or only animated in a simple way) at Dragon Con for time reasons, but I still fully intend to have it there. As such, I thought I'd spend a little bit of time to sort out some method to attach the parts (especially the head) together and then print the main bits that don't depend on the animatronic mechanisms for now. Then if I have any spare time in the next few weeks I can complexify it, and if not I can quickly print a simpler main body.
The picture shows the front half of the ball head and the lower cap of the body. I am printing the rear half of the head tonight, since I already have the filament loaded.
The fastener shown above is a 5/16-18 x 3/4 inch length bolt (roughly 8mm diameter for those with the metric system). This is what I'm using to attach the two halves of the ball together. Not the most clever or seamless system, but it should work for now.
There's a holder in the center of each half with a recess for the head of the hex bolt on one side and the nut on the other. You can see this on the left of the cross section below.
![[Image: 20220725-Four-Nines-Head-Attachment.png]](http://www.niflheim.net/droidbuilding/images/four-nines/20220725-Four-Nines-Head-Attachment.png)
Essentially, the two halves just screw together. I need to be sure to line the fasteners up with the external features such that the seam is tightest when the panel lines are lined up. This may require adding a washer or spacer to one side.
Below is the method I'm planning to test for keeping the head on the body. They are simply 1/4 inch flat washers glued to the inside of the sphere. You need to make sure they are made of a ferromagnetic metal and glued down fairly well because they like to stand on end when the magnetic field is applied. Also, I really should make the shell thinner for weight reasons where I can (the eye can't really be any thinner), but that might have to wait.
![[Image: 20220725_165742-small.jpg]](http://www.niflheim.net/droidbuilding/images/four-nines/20220725_165742-small.jpg)
You may have suspected there will be no washers where those arms attach to the shell, which is true. However, there are three magnets so the arms are unlikely to line up with more than one magnet at a time, and even when they line up with a magnet, the washers next to the arms will be pretty close to the magnet and might get grabbed anyway.
If this method doesnt work to help keep the head on ... well, there's always gravity. This droid isnt mobile by itself so it'll mostly be standing straight up
The lower cap part has a central hole for a 1/2 inch aluminum tube to act as a support. I'll make some sort of base to put this in for the droid to be stood on display. I *might* also put a concealed holder for the tube onto LD-F1 so they can drive around together.
There are also four screw holes through the sloped edge to attach the cap to the main body.
I've been focusing on LD-F1 for awhile now, and I'm currently fiddling around with component placements so I can finish up the chassis design. But this droid is still floating around in the back of my head (so to speak).
There's a very high likelihood that Four-Nines will end up temporarily static (or only animated in a simple way) at Dragon Con for time reasons, but I still fully intend to have it there. As such, I thought I'd spend a little bit of time to sort out some method to attach the parts (especially the head) together and then print the main bits that don't depend on the animatronic mechanisms for now. Then if I have any spare time in the next few weeks I can complexify it, and if not I can quickly print a simpler main body.
The picture shows the front half of the ball head and the lower cap of the body. I am printing the rear half of the head tonight, since I already have the filament loaded.
The fastener shown above is a 5/16-18 x 3/4 inch length bolt (roughly 8mm diameter for those with the metric system). This is what I'm using to attach the two halves of the ball together. Not the most clever or seamless system, but it should work for now.
There's a holder in the center of each half with a recess for the head of the hex bolt on one side and the nut on the other. You can see this on the left of the cross section below.
Essentially, the two halves just screw together. I need to be sure to line the fasteners up with the external features such that the seam is tightest when the panel lines are lined up. This may require adding a washer or spacer to one side.
Below is the method I'm planning to test for keeping the head on the body. They are simply 1/4 inch flat washers glued to the inside of the sphere. You need to make sure they are made of a ferromagnetic metal and glued down fairly well because they like to stand on end when the magnetic field is applied. Also, I really should make the shell thinner for weight reasons where I can (the eye can't really be any thinner), but that might have to wait.
You may have suspected there will be no washers where those arms attach to the shell, which is true. However, there are three magnets so the arms are unlikely to line up with more than one magnet at a time, and even when they line up with a magnet, the washers next to the arms will be pretty close to the magnet and might get grabbed anyway.
If this method doesnt work to help keep the head on ... well, there's always gravity. This droid isnt mobile by itself so it'll mostly be standing straight up
The lower cap part has a central hole for a 1/2 inch aluminum tube to act as a support. I'll make some sort of base to put this in for the droid to be stood on display. I *might* also put a concealed holder for the tube onto LD-F1 so they can drive around together.
There are also four screw holes through the sloped edge to attach the cap to the main body.