Introduction: Extreme Duty Pan & Tilt
I'm always tinkering in CAD and playing with actobotics. I put a simple tilt mechanism on my Cheetah 150 tripod/boom last year using a 90 degree bracket and 1/2 RPM motor. The problem I had was that the 1/2 RPM motor had just enough internal gear slop that wind would change the position of the camera and it would start bouncing within the gear slop.
I knew an easy way to fix that would be to add in enough external gear reduction to negate that internal gear slop. Then I thought, while I'm redesigning the tilt from scratch, I might as well add a pan function to it as well for a couple extra dollars.
"Abbreviated" parts list:
3/8-16 screw plate
1/2" double-clamping tube clamp
80T Aluminum spur gear
16T 3mm pinion
1/2" bore flat bearing mounts (2x)
Channel Bracket A
1/2" SS shafting
1/2" bore steel clamp
Motor mount (or any similar mount to fit the open side of 1.5" channel)
Flat Bracket A (2x)
1/4" Clamping hub
1/4" set screw hub
1/4" dual ball bearing hub
1/4" D shafting (4")
.770 x 1.5" Hub Adapter D
128T Spur Gear
16T 6mm pinion
Assorted 6-32 screws
Step 1: Tilt Pivot Mount
The first, and easiest step, is to attach the 1/4" hub mounts to the Flat Bracket A's. I elected to use one set screw hub which would stay permanently attached to the shaft, and one clamping hub which could easily be loosened for servicing. Use shorter bolts on one side, as this entire project is full of interference-fit components (YAY CAD for making them clear!)
Step 2: Pivot Gear Assembly
The next easiest part is making the 128T tilt gear assembly. The L brackets are NOT equal lengths. For this purpose, we want the short side going up and the long side going across. While this does throw the center of gravity off, it makes it much easier to tighten the camera down by being able to use a longer lever.
Attach the hub adapter to the gear with 4 bolts, followed by 4 more bolts from the adapter to the dual bearing mount. Doing this ensures that it will take a heavy load to make things try to go off-camber. It's arguable that using a surface mount adapter could allow using a second DBB hub module to make absolutely sure, but from experiments so far, things are plenty strong.
Step 3: Base Mount Assembly
The next "simple" assembly in this process is the base mount assembly. My Cheetah 150 boom/tripod came with a double ended spigot (yes, that's really what those are called), so I chose to use the 3/8-16 side.
Using 2 bolts, attach the 1/2" double clamping mount to the double flat bracket on a diagonal. Using 2 more bolts on the opposite diagonal, attach the 3/8-16 screw plate to the other side of the clamp mount.
Attach the pan motor to it's mount. I used an economy gear motor, and since no face mounts yet existed, I used a 1" tube clamp with some electrical tape to fill the excess void. Attach this assembly to the dual flat bracket.
Go ahead and stab the 3" x 1/2" SS rod in the clamp mount and run the bolts tight. I went ahead and coated the shaft and clamp in blue locktitie to make sure the rod was not coming out. While not the intent, I want to be able to run this unit inverted if I so desired.
Step 4: Main Body
The main body is the most difficult part of this build. Because holding up a 20+ pound camera/lens assembly is not for the weak, this design needed to be as solid as possible. I chose to use the single-extrusion Channel Bracket A for the upright, combined with a piece of 1.5" single channel to act as the reinforcing pivot.
First off, this step is made much easier if you have a long-reach wobbly-tipped allen wrench...which ServoCity gladly sells.
Attach the two channel pieces in phase, such that the 1.5" channel is on it's side. While it looks terribly unstable in this configuration, it is the strongest when finished. Take a motor mount or your favorite channel hub, and place it in the open side of the 1.5" channel, as shown. This boxes the assembly into a solid construction.
With a flat bearing mount inside the main channel, drop 2 screws through it into the hub mount in the 1.5" channel. With these 2 bolt in place, you can place 2 bolts on the other side going the opposite direction (up). I forgot to get enough screw plates, so I used a bracket I had handy. With these 4 bolts in and tight, the main body should be taking shape.
On the bottom of the assembly, place the 80T spur gear with the recessed side up and a flat bearing mount below, and attach 4 bolts on the 1.5" pattern holes. 2 of these bolts will go into the hub mount, the other 2 will require screw plates.
Attach the pan motor/motor mount assembly to the main channel bracket on the middle hole, and this completes the main body assembly.
Step 5: Install Pan Module to Main Body
With the pan assembly containing the 1/2" SS rod, slide the rod through the 1/2" hols in the lower bearing, lower gear, and lower channel. At this point, install the steel clamp, and continue sliding the rod until the assembly is seated and the pan gears are engaged. The lower bearing of the main assembly should ride on 2 bolts of the pan assembly- another interference fit that was made working possible with CAD. Tighten the steel clamp, and everything should be nice and cozy.
Step 6: Install the Tilt Gear Assembly
Place the gear assembly onto the 1/4" shaft, followed by the other bracket mount. At this time, you can then lower the assembly onto the main body. The two modules will line up using the second row of 1.5" holes on the main channel. Putting the first side on is easy, you will need to apply some pressure to get the other side in...it's not a perfect 2.25" fit. But a tight fit mean no slack!
Make sure to use shorter bolts on the side the gear is on...again, interference fit that just works!
Step 7: Tripod Bolt
So earlier on, I lied. THIS is the easiest part.
Get yourself a handy 1/4-20 half inch or so pan-head bolt, and run it through a 1/4-20 screw plate.
Take a piece of beam (3.08 I think), put a spacer on it, and bolt it to the screw plate.
This inserts through the bracket on top, and allows clamping the camera down to the plate securely.
Step 8: You're Done!
Stab the assembly onto your favorite tripod/boom, and wire it up!
I wired up using SC's heavy duty braided servo wire. I have black wired as common, red for tilt, and white/yellow for pan. I simply used a Servo Y harness and cut up a couple of standard cheap 12" extensions for pigtails.
At the control end, I used a DPDT switch in standard reversing wiring, and added a pushbutton to control each motor.
My Cheetah 150 boom/tripod was $150 at the local camera shop ($120 online) and is rated 15 pounds at 13 feet straight up, or 6 pounds at 5 feet up and 4 feet out.
I've tested it with the big lens and T3 on the end and 20 pounds of counterweight sand. It was almost balanced, needed more sand.