I need to come up with a better name. But so far it is moving along wonderfully. I had to make some part adjustments, the list is NOT updated as of Aug/24/2017. I will get around to that when I have more time.
So when we left off last time, most of the parts were in, and the Pan/Tilt frame was welded together.
The motor mounts were installed next, and that was a bit of a pain in the ass. I wanted to weld them on but the welds did not take. I think it is a different kind of aluminum. I ended up squishing one of the mounts in the process, so I went the old school route and bolted them on. The easiest way is to mark the holes and drill them through BOTH sides of the frame. That gives you a small hole for the hex wrench to go through to reach and turn the 6-32 screws. Once those were in place I used some aluminum epoxy filler to fill in the holes. To make sure the screws did not back out I used locktight on the threads and covered the screw heads in the aluminum epoxy.
As for the placement of the mounts, I just sort of eyeballed it.
You can see the epoxy on the frame in the previous picture, it is covering the holes drilled in the frame used to tighten the screws to the mounts.
The frame was painted with just your typical metal friendly rattle-can spray paint. I chose gloss white for this project.
I spent quite a bit of time cleaning the aluminum and prepping it for paint, yet i still have a couple tiny areas that flaked. I might strip all the paint off and try out powder coating.
The cradle was made from a couple pieces of 2in x .25in aluminum bars. I cut them to the desired length, then held them together with some 90 degree clamps and drilled/tapped some holes to join them together.
Now that part is out of the way, I wanted to get the head mounted to the rail.
The extrusion has slots with some bolts in it, makes for an easy connection. I took a 2x2inch x 1/2 inch piece of aluminum and drilled some holes in it. 4 bolts facing down to connect to the anchors in the extrusion, and then 4 6-32 x 1 inch screws facing up into the larger hub clamp.
Easy enough. All of this can be done with a few bits and a drill press, just gotta make sure to countersink the holes so the heads recess under the surface. I did go ahead and add a hole in the middle that you cant see with a 3/8th inch tap so the pan/tilt can mount direct to a tripod.
This bracket gives a nice solid connection. My intention was to make this a 2 part connection, with the Rail mounted part using a 3/8th inch screw post, with a small 1 inch tall x 1.5 inch wide round base on the head with a 3/8th inch tapped hole. That way i could unscrew the head anytime i wanted, and even install a leveling plate in case I wanted to hold the rail at an angle. However I had one of those HOLY SHIT moments when cutting some 1.5inch aluminum stock. The piece I was cutting off ended up getting sucked up into the miter saw with a nice gunshot sound. So now my diablo aluminum blade is jacked up. This is the 2nd blade I have managed to destroy, and at 60 bucks they are not cheap. 🙁
I wanted to get this mounted so I had to improvise with what you see here.
I am super excited about how this project is turning out. I have to pick up a new aluminum blade so I can make the connection plate beneath the rail so I can connect it to to a tripod. Unfortunatly the extrusions walls are too thin to just punch and tap a hole, I’ll need a thicker plate beneath it and then secure it to the rail via the channel connectors.
Things I still need to work through
I am not overly happy about the paint. I spent quite a bit of time prepping the aluminum and it is already chipping in some spots. Being a studio queen, this would probably be fine and look great for years, but I would rather try to tackle this issue sooner than later. I have been reading up on powder coating, and I think that may be the right way to go.
The problem with avoiding expensive CNC mills on this project is that the holes for the bearings are limited to the size of the bit. if using a CNC, i could measure these in a few thousandths of an inch and get a nice tight fit. When looking at the photo, you may be able to tell that things are not perfectly held at 90 degree angles. I am looking into some possible shim ideas to tighten these up a bit.
The Pan/Tilt got pretty heavy with these motors. This is not really a problem, but the motors are a little bit overkill for this project. I think next time some heard NEMA 11’s would be more appropriate. Aside from that, I am very pleased with how this is going 🙂
I still need a place to mount the Arduino and driver board. I have not picked out a box for it yet either.
Overall current impression
I have to admit, I am very pleased with how this is going. It looks fantastic, and once I get the rest of this dialed in i have no doubt this will be a very capable system and a wonderful addition to my team of photography robots. The bearings are nice and smooth, everything is held together nicely, and I cant wait to fire it up, I just have to get the tripod connection worked out first. This will probably actually be a 6 axis robot, if I can get both focus motors mounted for Focus and Zoom control, and then I plan to have this system drive a turntable as well.
So while it is not perfect yet, by the time I am done with it this will be a rock solid little robot.
Heads up, if there are any animators or timelapse photographers that are interested in a dragonframe moco rig like this please let me know. I hope to have enough information here where an enterprising person might be able to build their own, and if somebody wants to try I am always willing to offer assistance. However, if somebody wants one of these pre-built, that is also a possibility. Cost for a complete dragonframe ready system would be about $1200+ depending on rail length, any extra design considerations, etc. Email me, Chris@biolapse.com and we can discuss it. Turnaround time is not fast (2-4 weeks depending on part availability and my schedule), but I would keep you in the loop on the progress of the build.