Step 1: Stuff You Need
Here are the parts you need:
4 x 1/4 Nylon washers
1 x 8-32 x 1/4 Chicago screw set (it is a 2 part set that screws into itself see pic) (Poulin #222-269)
1 x 3" Swivel or lazy susan flat ball bearing. (In the cabinet hardware aisle at Home Depot)
1 x 28ga 8" x 10" Sheet metal block end (used for blocking cold air returns)
1 x Hitec HS-322HD servo motor (general purpose type), you can use other servo motors, but be careful; some, (like Futaba), go in the opposite direction (Pan motor)
1 x Hitec HS-755MG servo motor (heavy duty 1/4 scale with metal gears and ball bearings) (Tilt Motor)
1 x Hammond 1411N enclosure or deep octagonal electrical box with cover or deep square electrical box with cover
12 x 4-40 x 1/4" machine screws
8 x 4-40 x 3/4" machine screws
2 x 4-40 x 1/2" machine screws
24 x 4-40 nuts
1 x 4-40 washer
1 x 1/2" Rubber grommet
1 x 1/4-20 x 1/2" machine screw (optional camera mount)
1 x 1/4-20 nut (optional camera mount)
A servo controller of some type. There are many kits available (google "electronic kits" or try www.bpesolutions.com). A DMX controller is available at http://home.att.net/~northlightsystems/. An RF style controller is available at most hobby shops (like one for a car or airplane - needs 2 servo outputs), there are a few on this site and I will post mine when it is working and not jittery. It may be advantageous to have the controller before you start the project so that you can test your movements as you go.
Aviation Snips or Tin snips
Drill press (or a drill and a really steady hand)
Drill bits - 13/64", 1/2", 27/64", 7/64", 3/32"
4-40 metal Tap - Optional (see text near end of step 6)
Optional but a great way to make really round holes is with a step bit and a 1/4" bit
A bench vice or a sheet metal bender (called a metal brake)
Staedtler Lumocolor fine point marker (fantastic marker with a slim body) or Fine point Sharpie marker
Single hole punch (three hole will work too)
Step 2: Prep the Servos and Dry Fit
In this step we will mount some screws to the servos to make it easier to figure out where to drill the mounting holes in the brackets and enclosure.
Mount the rubber shock absorbers that come with the servo into the 4 mounting holes in the servo.
Use 4 x 4-40 x 3/4" machine screws and 8 x 4-40 nuts for this step. Put a nut onto each screw and thread it as far as you can. Mount the screws in the shock absorbers so that the threaded end is sticking out on the same side as the servo shaft. Thread another nut onto the screw to hold it in the shock absorber.
Repeat with the other servo.
Now fit the large servo to the longer bracket. The 1/2" hole should fit around the shaft collar and the metal should be flush with the servo body. You will probably have to adjust the nuts on the 4-40 screws so that the metal will sit flush, just be sure that the screws are still in contact with the metal of the bracket.
Position the servo so that the body points towards the center of the bracket and so that the short side of the servo body is parallel with the bend line nearest to it.
Mark the mounting holes by tracing around as much of each of the 4-40 screws as you can.
Remove the servo.
Drill 7/64" holes at the center of the locations you marked. You will have to guess a little bit at where that center is, but as long as you are very close everything will be fine.
Dry fit again. Place the servo in the 1/2" hole and see if the screws will go through the holes you just drilled. If not you can "adjust" the holes as needed (as in redrill them).
Step 3: Bend the Metal
Now you can bend the metal. If you have a metal brake, now's the time to impress everyone, if not you can use the following method. Clamp the sheet metal in a bench vice with the bend line along the top of the vice jaws. Be sure it is as straight as possible and the vice is firmly clamped. Now holding the top of the bracket, gently bend it towards you as you tap along the backside of the metal with a hammer. Start tapping at one end and move across to the other end. You are not trying to bend the metal sharply but rather gently so that you only move a few degrees in each pass. When the metal is finally flush against the top of the vice you are done and you should have a nice 90-degree bend.
Flip the metal 180 degrees and repeat. You are making a U shaped bracket so position it in the vice accordingly.
Repeat the above bending for the short bracket.
At this point you can mount a top plate onto the short bracket. I chose to mount a piece of wood because I can then easily attach almost anything with screws to the pan and tilt head. If you are going to mount a camera, you can drill a hole through the bracket and mount a Â¼-20 x Â½" machine screw to the bracket. Be sure to secure it with a Â¼-20 nut as your camera only wants about 3/16" of the threads.
Step 4: The Swivel
Mount the swivel to the underside of the long bracket so that the uprights of the U face away from the swivel.
Place the swivel in the center of the bottom of the long bracket and mark its mounting holes on to the long bracket.
Remove the swivel.
Using your ruler and a marker, draw a line from one corner screw hole (that you just marked) to the opposite corner screw hole passing through the center of the bracket. Now do the same for the remaining 2 corner screw holes. You should now have the 4 corners connected with a big x. This will give you your exact center point of the swivel. (Very important as this will be where the small servo attaches.) Alternately if the holes are in really weird places, trace the whole swivel base plate and then use these corners to find center.
Drill a 9/32" hole at the center point you just created.
Drill a 7/64" hole at each of the 4 corner screw holes you marked.
Place the swivel on the top of the Hammond enclosure (or on the cover plate of the electrical enclosure). Be sure it is not the same face of the swivel that you used to mark the mounting holes on the bracket. If using the Hammond enclosure, place the swivel closer to one of the short sides and centered on that side.
Mark the 4 corner mounting holes on the enclosure (or cover plate).
Remove the swivel.
Same as above. Connect the opposite holes to make the big x and find center. Alternately if the holes are in really weird places, trace the whole swivel base plate and then use these corners to find center.
Drill a Â½" hole at this center point.
Drill a 7/64" hole at each of the 4 corner screw holes you marked
Step 5: Center the Servo
Determine the center of the servo. There are a few ways to do this.
The best way is to connect the servo to the controller that you plan to use, power it up and set your control to its center position. Then remove power to the servo, thus leaving it set at the control's center position.
Mount one of the servo horns (plastic parts that come with the servo) to the servo shaft so it will be easy to mark where center is. I like the circle one for this step.
Now make a mark on the horn perpendicular to the short side of the servo. You want the mark to be close to the short side.
The drawback is that the servo is "calibrated" to this controller and may not work with another controller.
The following method will find the true center of the servo's travel. Fortunately most controllers allow you to adjust where they think the center point is, so this method should work for almost all controllers.
Servos only rotate 180 degrees, so if you mount one of the servo horns (plastic parts that come with the servo) to the servo shaft it will be easy to see where center is. I like the circle one for this step.
Rotate the shaft by hand as far to one side as it will go. Mark a line on the horn perpendicular to the long side of the servo.
Now rotate it to the other extreme. It should have travelled 180 degrees.
Rotate the servo shaft back 90 degrees and voila you have the servo centered.
Note where the mark is and carefully remove the servo horn from the servo. You do not want to move the shaft at this point. If you do, simply repeat the above steps to find center again.
Step 6: Mount the Pan Servo
Put the side of the servo horn that does not connect to the motor into the hole in the bottom of the long bracket so that it is on the bottom of the bracket (same side as the swivel would mount).
Line up the mark you made on the servo horn with one of the open sides of the bracket. The mark should be centered to the open side of the bracket.
Drill two 7/64" holes through the horn and the bracket. I usually do this through some of the existing holes in the servo horn. It shouldn't really matter which ones, except try and do them 180 degrees apart.
Install a 4-40 x Â½" machine screw in each hole in the bracket and secure with a 4-40 nut. Now push the machine screws through the bracket and secure with two 4-40 nuts. The servo horn should still be centered in the hole in the bracket but not directly against the bracket.
Attach the swivel to the bottom of the long bracket (the servo horn should be in the middle). Use 4-40 x 1/4" machine screws and nuts (4 of each).
Place the completed base on the top of the Hammond box (or enclosure cover) and line up the mounting holes. The servo horn should also be centered in the hole in the enclosure.
Dry fit the pan servo. The collar around the servo shaft should fit snugly in the hole in the enclosure and the shaft should be inside the horn.
Now check that your swivel mounting holes still line up. If not make the necessary adjustments (redrill if needed).
Remove the servo. Try to keep it centered.
Temporarily attach the swivel to the Hammond enclosure or cover plate with four 4-40 x Â¼" machine screw and 4 nuts.
Line up one of the open ends of the bracket with the short side of the Hammond enclosure. This will be the front of the unit.
Reinstall the servo. It should line up so that the short side of the servo (with the wires coming out) is parallel with the front of the unit.
Using the same method as we did with the large servo (step 4), mark the mounting holes for this servo.
Remove the servo.
Drill out these 4 holes with a 7/64" bit, unless (like mine) 2 of the holes will go through the swivel. In this case, drill out the 2 holes nearest to the center of the swivel with a 7/64" bit and drill out the other 2 holes and the swivel with a 3/32" bit. Tap these 2 holes with a 4-40 Tap. This can be somewhat optional. You could drill out all 4 holes with the 7/64" bit and just use the far 2 holes (with screws used as pins) to keep the motor from torquing
Disconnect the swivel from the Hammond enclosure (or cover plate).
Mount two 4-40 x Â¾" screws through the top (same side as swivel mounts on) of the enclosure (or cover plate) and secure them on the bottom with a nut on each screw.
Reattach the swivel with the four 4-40 x Â¼" screws and four nuts.
Remove the 2 machine screws closest to the servo shaft from the pan servo.
Place another nut on each of the machine screws that are mounted on the enclosure (or cover plate). Remount the servo on these 2 screws. The servo should line up with the horn as described above.
Put a third nut on each of the screws and tighten. These will hold the servo to the enclosure (or cover plate). Tighten the second nut down to the servo.
Screw the other two servo screws into the tapped holes (or just into the holes).
Make sure you attach the servo horn hold down screw. You can leave it somewhat loose so that if you didn't get the servo perfectly centered, it can move a little.
Step 7: Mount the Tilt Servo
First, Drill a 7/16" hole in the top of the enclosure (side the swivel is mounted to) as close to the short side of the enclosure as possible. Insert the Â½" grommet. This hole is for the tilt servo wire to go through. Therefore, you do not want the swivel or brackets to be able to damage the wires by clipping the hole.
Mount the large tilt servo using four 4-40 x Â¾" screws and 8 nuts. Push the machine screws through the side of the bottom bracket towards the center of the bracket. Secure each one with a 4-40 nut. Push the servo over the screws. Thread another nut on each screw to hold the servo to the bracket.
Drill a 7/64" hole through the second hole from center of the single arm servo horn.
Center the servo but this time use the single arm servo horn. If you don't remember how to center a servo, see step 5.
Remove the horn. Careful not to move the shaft.
Mount the top bracket with the big hole over the servo shaft.
Secure the other ends of the brackets with a Chicago screw set and nylon washers. Take the female part of the Chicago screw set and place a washer on it. Then slide it through the small hole in the side of the top bracket. Now slide two more nylon washers over the Chicago screw. Now insert it into the small hole in the side of the bottom bracket. Slide one more nylon washer over the Chicago screw and thread the male part into the female part. Now you have a pivot point.
Mount the servo horn so that it points down (towards the Hammond enclosure).
Make the top platform parallel with the Hammond enclosure (or cover plate)
Mark the hole that you drilled in the servo horn on to the top bracket.
Disassemble the two brackets.
Drill a 7/64" hole at the spot you just marked on the side of the top bracket.
Thread a 4-40 x Â¼" screw through the hole in the top bracket that you just made. Thread it from the inside of the bracket to the outside. Place a 4-40 washer over the screw. Now put the servo horn over the screw and thread a 4-40 nut on to the screw to hold it in place. The servo horn should also be centered in the 27/64" hole you drilled in the side of the top bracket with the side that connects to the servo facing the inside of the bracket.
Reassemble the two brackets. See above. Make sure that after you connect the servo horn to the servo that you put the retaining screw in.
Rotate the top bracket by hand. The two brackets should be close to touching (preferably without actually touching).
Congratulations it's done! Now connect it to the controller of your choice and away you go. I will post an instructable of how to build a controller of your own, just as soon as I get it working the way I want without a microcontroller!!