Homework - Cyril Wichers

Nice work, as always!

Top plate, adapter for mounting the head and links from servos to top plate finished.

On further inspection, it turned out that there was a piece of pipe in the neck of my mannequin head (probably for attaching it to the body). I machined a piece of aluminium to fit inside, leaving a flange, so the head would rest on it (I glued the adapter inside the head using epoxy when the mechanism  was finished). I also drilled a hole for a center pin.
Then I machined the top plate. It has a pin on the top and on the bottom. One is used as a center pin to locate the adapter, the other is used to attach the top plate to the universal joint. I drilled two holes at 90 degrees and machined a couple of brass pins to fit inside them. These are used to attach the rod ends and provide enough clearance for them to rotate. Finally, I drilled and tapped three holes for the screws that attach the adapter to the top plate.
I made the links out of 5mm silver steel rod, which I turned down to 3mm at the ends. I cut an M3 thread on them to attach the rod ends.



Nice snug fit between the adapter and the top plate:

https://www.youtube.com/watch?v=LOFSfjjykRc

Head fitted.

Attached the receiver and programmed the transmitter.

I mixed the servos for the "nodding" motion, so I can control them with one stick. When I move it up or down (pitch), the servo's move in the same direction. I also mixed in the roll, so when I move the stick to the side, the servos move opposite to eachother, which produces the "curious puppy"- look.



The third servo is attached to the other stick (rudder), to control the turning-motion.


https://www.youtube.com/watch?v=ZLBPmAUszlw&feature=youtu.be

Unfortunately, there's some play in the rod ends and the universal joint, that's why it's a bit wobbly.

Thanks for the compliment! Nice work on your part too, I can imagine it's quite a challenging project if you're not used to working with metal.

Thanks Dave! Machining has been a hobby of mine for years, although I haven't been doing a lot of it for projects here. I bet there are people on the forum who are convinced the only tool I own is a 3D printer ;-)

Here's a pic of my shop:



As to the neck mechanism; I sourced some better quality rod ends, which eliminated some of the play/wobblyness. What's left looks to be caused by play in the servos themselves, probably because they're cheap Chinese ones. These are great for prototyping, but not so much for heavy duty use (as in: balancing a 2 lbs glassfibre mannequin head) For now they'll have to do, since a set of Hitec servos will set me back almost 150 Euros.

Excellent work Cyril! That looks amazing as usual. I envy those tools you have there and your shop. I'm doing my work on the back porch outside. It gets the job done!