Death Star Laser Turret - Self Elevating Guns - Stepper Mounted

This is a remix of the concept of the turret topper by KoolStef but with all new parts from thing 4433524 with the auto elevating guns. The base should fit a standard printer stepper motor with mounting holes spaced at 31mm.

Important: It is highly recommended that you thermally calibrate your filament for this assembly to work. Use one of these calibration pieces to do so.
https://www.thingiverse.com/thing:1037301

https://www.thingiverse.com/thing:2502677

As the turret is turned the weight of the guns will lower them back down after the cam profile raises them. Every 90 degrees of rotation will either raise the guns or lower them.

For this to work properly there is a lot of surface preparation of the parts required. The squish layer edge on all the parts needs to be removed. The gun barrel pivot needs to be smooth and the cam profile needs to be smooth. As you smooth out the surfaces keep test fitting the gun in the turret and when the guns can fall back down on their own accord when lifted up then it is ok to lock them in place with the turret hub. The turret hub can be pushed all the way into the turret by pushing it in with the tower hub. The turret hub will be a tight fit but can be carefully pushed back out by raising the guns all the way up and pushing down.

The tower has two versions included here. One with a self supporting layer for the cam profile that does not require supports if you can span 15mm of bridge and the other with the profile cut all the way through that requires supports. The self supporting layer needs to be cut out making it easier to smooth out the cam profile. Hobby files and a sharp hobby knife work very well for the clean up process.

The spindle will be a tight fit on the stepper post. Over time it can loosen up especially if removed and put on multiple times. A smear of super glue on the inside of the spindle with a tooth pick, let it dry completely, and smooth back out with some very light filing will restore it. I have included a version of the spindle that is keyed for a stepper shaft with a 0.5mm anti slip flat on it as shown in the pictures of the stepper motor example. The keyed spindle has a small notch mark at the bottom edge to indicate what side lines up with the flat on the stepper shaft.

When gluing the turret hub to the spindle make sure you insert the spindle through the tower before doing so. Put small drops of super glue on the 4 shoulders of the spindle and press the hub on. By turning it upside down with the base in place on the tower you can make sure the hub is perpendicular and the spindle is centered straight.

The turret and the guns should not be glued on but should be able to be pulled off for smoothing adjustments as needed.

When mounting on the stepper bolt the base on but do not tighten it all he way. With the spindle and tower assembly in place you can center the assembly on the stepper post and then tighten it down. When pressing the turret on it will push the spindle all the way down on the stepper post so that the turret is flush with the tower top.

A video of this working on a stepper motor can be found here:
https://www.youtube.com/watch?v=l_azaSz6PAk

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