My goal was to build a camera boom for may Super 8 film project. I looked at what others have done in order to get a a good idea of how they worked. I build a model out of 1/4" dowel just so I could see the mechanics that keep a camera in one position throughout its range of motion.
I started building this project without the idea of making it an Instructable so I guess I'll try to reverse engineer my boom construction and present it to you guys as my first Instructable.
Stuff I bought-
1 8" x 5' cardboard form from Home Depot (building supplies)
2 1-1/8" x 10' conduit pipe from Home Depot
1 3" x 3' ABS section from Home Depot- they have a rack of them in the plumbing dept.
4 1" x 2" PVC pipe connectors from Home Depot
1 1-1/4"x1-1/4 aluminum angle from Home Depot
2 5/16" x 3' threaded rod from Home Depot
1 5/16" turnbuckle
1 2part epoxy kit
1 used camera pan head won on eBay ($10.50 + ship)
Total cost: $55 approx
Stuff I had on the shelf-
8 inline skate bearings (from my skate box)
1 large iron plate from patio umbrella stand
1 Celestron telescope base (I can reuse as telescope base if I choose)
1 piece 8"x8" x1-1/4 clear pine
Picture frame saw
Assorted hand tools- File, drill bits, wrenches, etc.
Step 1: Base Column Construction
As the amount of weight that a camera boom supports is not huge, maybe 30-40 lbs. max, I was looking for a way to mount the boom without using a tripod as I only have two and they are slated for other uses for my film project.
I started by guesstimating how high the base should be. This is determined by the max height of the boom would need to rise. As this is a garage project, it turned out to be 36". So, I cut 24" off the cardboard concrete form by carefully using my picture frame saw. It has a special saw edge that was gentle on the cardboard form.
Next, I needed a platform to mount the boom system. The easiest way was to cut a circle that matched the ID of the cardboard form, about 7-3/4". I inserted this at one end and epoxied it. The epoxy would probably be strong enough but I added 4 dry wall screws with flat washers anyway.
I also drilled a 5/16" hole in the center to receive the 5/16" threaded rod.
Item next was to create an access hole so I could get my hand inside to assemble the steel plate base. I cut 2 holes about 6" from the top with a 2-1/2" hole drill. Cleaned it up a bit with a shop knife. I can get my hand inside to assemble the parts that hold base together.
And, while I had the big 2-1/2" hole drill set up I drilled a single hole in the opposite side to make it easier to drag this beast from place to place.
So, what we have now is a 3 foot high cardboard form with a wood top epoxied and screwed in place with some screws for extra strength. On to next step...
Step 2: Steel Plate As Weighted Base
I just happened to have this 1/2" X 2' plate of steel that is a patio umbrella stand base. It has a hole in the center so I didn't have to drill it. And, it already had some feet on it so the nut on the bottom wouldn't be a problem.
Here's how I assembled-
All that has to be done is to tie the base column to the steel plate with a 5/16" threaded rod to the wooden top and tighten it down with a turnbuckle. At the wooden top end I used a 5/16" screw-eye with a piece of the "eye" cut out so I could connect to one end of the turnbuckle. I also had to countersink the the nut and washer so the boom mount would fit.
Once all hooked up I centered the column on the steel base and tightened the turnbuckle a couple of turns.
BTW: the compression strength of these cardboard forms it pretty good. I didn't stand on it or anything drastic, but I'm pretty sure it could hold at least 100 lbs.
One last step on the base-
My boom mount is the base of my old Celestron 4" telescope. I know, pretty drastic decision to modify an expensive toy.
I has several 1/4" tapped holes in the bottom. I just matched up 2 so I could run bolts from the bottom of the wooden top.
Step 3: Layout Support Tube
If I had to do this project over I would build a tool to create the bearing mounts and aperture for the boom rods to reside.
The problem is laying out needed drill points on a ABS tube. The easiest tool would be just a box of 4 sides (no ends) that is exactly the OD of the piece of 3" ABS that will support the booms. That way you you can find the exact center drill points. I was stupid or lazy on this and I was off by some wiffy-jiffies.
Layout two holes to receive the bearings, and two holes 90 degrees for the booms. You want the holes for the booms to be large enough so you can tilt the boom up and down.
I choose 5-1/4" centers for the bearing holes. I had a drill bit that was almost exactly the diameter of the
1" PVC connectors (4 of them). As you can see from the picture there are 2 on each side. Each one of these 20 cent PVC items house 2 inline skate wheel bearings. Before you can mount these on the support you need to ream them out a bit to receive the bearings. I used my Dremel drill with a sanding tool. It kicks off very annoying PVC dust so do this little task where you are not going to make a mess.
So, now you've reamed out the 4 PVC connectors and pressed the bearings in. Two per piece adding up to 8 bearings in all.
On to next step....
Step 4: Mounting Bearings
The object here is to mount these pieces of PVC in the holes you drilled in such a manner to give your boom an nice bearing surface to move on.
Before you can mount cut 2 6" pieces of your remaining 5/16" threaded rod for your axles. By the way, 5/16" is the exact ID of the bearing.
Were going to epoxy these parts in place but before you do put each part in the support with the axles inserted. This way you can get perfect alignment. The PVC parts should go half way in with a bearing on the outside and a bearing on the inside. Make sure you you have at least 1-1/8" clearance or you wont be able to insert the booms.
Once you are happy with fit and alignment do the epoxy thing and reassemble WITH the axles inserted.
On to next step...
Step 5: Mount Support to Base
In my case I cheated and used my Celestron yoke to hold the boom support subsystem.
I just removed the telescope and positioned the support subsystem and drilled a single hole through everything. I had to jury-rig the assembly as the dilling was not perfect. But it is stable.
If I didn't have the Celestron option I think I would have proceeded to use an ABS end cap and mounted it to the wooden top of our base. I think it would be strong enough. I would have used 3 or 4 1/4" bolts with very large washers. I doubt that you would even need to use ABS cement. Once it is in place on base I don't think it would go anywhere.
We have built and assembled the base unit
Lay out and drilled the support column
Assembled bearings and axles
Epoxied axle system in place
Created a way to attach support subsystem to base.
Step 6: Boom Parts
There are four parts to be fab'd before we can do final assembly:
2 end caps made out of 1-11/4" angle aluminum
2 booms made from our 2 10'x 1-1/8" pieces of conduit
The end caps will have 2 axles on 5-1/4" centers w/o bearings.
I cut 4 pieces 7-1/2" each.
I then fit the pieces to form a U so ends of boom will be contained inside. Just looks neater. I've seen some booms where someone used a piece of 1"x1" metal and attached with bolts leaving the boom ends exposed.
Once you formed the U find center and drill 2 1/4" about 3" apart. I used 1/4" counter-sunk machine screws with lock washers and nuts on inside.
Pick one of these end caps to be your camera end. If you have acquired a pan head to mount camera on you will need to drill a 3/8" hold to bolt up the pan head to the end cap. Center it and drill it.
On the sides you need to drill 2 5/16" holes for the axles. These, too, are on 5-1/4" centers. I made them 1/2" from the back of the U so everything is pretty well centered and looks clean. This did require one more minor step that I will cover in the boom fab portion of this step.
I believe the boom sections are the hardest part to get perfect. Here's why:
You need three sets of 5/16" holes perfectly aligned with the holes through the widest part of the conduit.
I do not have a machine shop so I was left to my own devices as to how to do this.
I first found the middle of the conduit I was using. I chose to have booms only 8 foot long. I don't need the extra 2 feet as my camera shots are to be all close ups and of miniature stuff.
Center one hole at 4 foot mark, the other 2 at the ends 1/2" from the end.
To center I used my laser picture hanging tool. For the center I used a piece of tape with a very small nail pushed through so the laser had something to shine on. The close end was easy. The far end was a problem as laser spreads a bit. I used a piece of paper behind end of conduit and it lit up the end.
To drill I used my neighbor's drill press. I used a jig to hole conduit so I could get both sides of conduit drilled at same time.
All holes came out perfect.
I used a file to cleanup holes.
One last step is to chamfer a bit off of the ends of the conduit. If you don't the conduit will be constricted as soon as angle of boom hits the end caps.
I think all of the parts are complete.
Next final assembly...
Step 7: Final Assembly
Attach your support system to the base. I used 1/4" x 2" bolts used to assemble computer tables. They get tightened using an allen wrench.
Next, insert one of the booms into lower bearing position. You will have a bit of space between the inside bearings. I inserted the axle then added a 5/16" nut, screwed it through to the opposite side of conduit and added 2nd nut.. After centering using a couple of wrenches at the same time, I finished off using 5/16" aircraft self-locking nuts. Don't use a washer as it will defeat the bearings.
Next assemble end caps using 5/16" x 2" bolts or you probably have some of the threaded rod left over. Just put it together for fit. If everything works ok then we can do final.
I used some neoprene washers between the boom and the end caps just to make it smoother.
Don't tighten too much. I used the aircraft nuts here.
Final step is to mount your camera pan head using a 3/8" by 3/4" bolt with large flat washer. I had to cut down the bolt as pan head didn't go deep enough. Use a file to clean up thread for easy camera attach.
Lastly, you will need to make something to hold ballast as a counter weight. I'm going to find something and fill with sand.
No, it wont be out of the cat box.