Built a dolly
 

So, I did it. I built something.

I stole/borrowed the Matthew Cherry design posted elsewhere, almost exactly.

http://www.birthofthecool.com/dolly.html

So, you can see my spectacularly crappy photos of it (they're frame grabs from my XL2 taken at night outdoors).

The only real issue so far is that as the wheels turn, the seem to unscrew themselves. Each wheel (these are inline wheels) has a washer on either side of it, and a nut on the outer edge against the washer. The wheel turns the washer, the washer turns the nut, and it starts to unscrew. Any way to prevent this? Do I just need to oil everything? This world of building stuff is new to me.

Josh,

Good Job. I mentioned in another thread I just built one as well. To keep wheel nut from loosening, use the locking kind of nut with the white teflon/plastic insert.

I've never heard of those before. I'll go look tomorrow. Are they found at any hardware store?

If anyone wants details (detailed parts list, etc.) let me know. I won't even charge anyone $40.

wheels unscrewing aside, should I oil all those parts anyway?

By the way, if it was unclear, the url link in my initial post is to Matt Cherry's stuff; the dark grainy pics at the bottom are mine.

Josh,

The lock nuts should be available pretty much anywhere. The bolt that serves as an axle should be 5/16".

The bearings I bought for the wheels are sealed. I don't think I could lube them if I tried. Maybe you need to back off on the nut slightly if there is too much friction.

Lubing the bolt/nut may cause it to loosen more. You can always use some 'Loctite' to help hold the nut in place.

Actually, my bolts going through the wheel are 1/4". I don't think 5/16 would fit, it's just barely fitting at is.

No lubing, then. I'll find these locking nuts.

When I was thinking of the oiling, though, I meant oiling the washers and nuts, so they'd slide against each other with no friction.

I'm surprised that the bolt is 1/4". In Dan's 'Killer Camera Rigs' book he says that all skate bearings are 5/16". I don't suppose it matters as long as the bearings spin and they fit sort of snug.

I think if you lube with WD40, you might pick up dirt etc. I've heard of a teflon spray lube that doesn't attract gritty stuff.

Yeah, I tried wiggling the bolt inside the bearing, and it doesn't seem like there's another 16th of an inch of room in there.


The locking nuts worked great! Only problem is that Home Depot only had 6 left. So only half the wheels have 'em. I gotta drive around the damn city looking for stupid pieces of metal and plastic.


Seems like the wheels without locking nuts (I hope that's why) are tightening as you push the dolly, loosening as you pull. I hope the locking nuts'll fix all that. And I may have to space the wheels more, as there's not much of a groove for the pipe (I got some 1.5" PVC) to fit into. I guess I could just use more washers.

1.5" is pretty big PVC pipe. If you're having trouble, you can always use 1" or 3/4". Dan's dolly was designed for 3/4" metal (to run up high) or PVC for the ground. Of course then you're stuck with the 1.5", unless HD will take it back.

It sounds as if the nuts are tightening on the wheel when you push one way and loosening when going the other???

I don't think they'll take it back, being that I cut the 10 foot sections down to 8 feet.

I guess I just assumed 1.5" was the proper size. . .it looked like the same kind of pipe Plus8 had when I borrowed their skateboard dolly. Yes, I do realize a skate board dolly hugs the wheels more.

I thought about getting metal, but for some reason everyone always mentions using PVC as track.

I'll try working with the 1.5" pipe for a while, see how it goes.

Yes, you're right about the nuts. I think getting the locking ones will solve that problem. It takes a tremendous amount of force to twist the locking nut, so the mild pressure of a washer shouldn't be able to do it.

Yeah the PVC is standard stuff. The reason the metal (electrical coduit pipe) is good is that you can then run the track elevated, because it's strong enough to support the weight of the dolly,tripod and camera (but probably not a cameraman). A good trick i read about was using sandbags to prop the track up for quick set ups over really rough ground.

You can do the same with PVC if you fix to a wood base (2x2 or 2x4). Drill a -just big enough for the screw to fit through- hole on top of the PVC pipe, and screw the pipe down every couple of feet. You then have the PVC track mounted on a rigid wood base for quicker set-ups on rough terrain. This would also work over elevated areas.

Oh BTW, I also read somewhere it's a really good idea to screw in a hook or two into the dolly platform. Then run a bugee cord up and around your tripod and back to the dolly to prevent any tipping (yikes!).

That's not a bad idea, about the hook.

I have a sandbag I can use to secure the tripod.


I forgot to mention, the only problem with the design I used (again, Matt Cherry's design) is that the push will only come off if you unbolt part of it--you can just unscrew it. My solution was to have one of the flanges be unboltable (I mean, technically they both are, but one of 'em should always stay on) then the whole thing swings out, and you can start diassembling. I could've just made a T-bar, but I didn't.

Ok, I keep lying when I say "the only problem. . ."


So, here's some more--

The way the pushbar is assembled, it tends to unscrew (only up to a point of of course) if you put pressure on one side. Any way to fix this? Remember, I need to be able to disassemble it for transport.

Also, the pipe is just to big, the dolly keeps rolling itself off the PVC. So what's the proper diameter for the inline wheels? I'm assuming the wheels are supposed to be as close together as they can without having friction impede them from spinning.

Hmmmm.

I don't have a push bar handle yet, but was leaning toward a T-handle. I shot some footage yesterday and I can see where the dolly works more smoothly with weight on the platform but I was just walking beside it.

If the handle parts thread together, there may be an opportunity to drill a hole and put a cotter pin through. Or you can use the old standby, gaffers (duct) tape and cover the join between the 2 parts. I doubt that they would be able to unscrew with the tape over them.

If the pipe's too big, I'd ditch it. I used two washers between the two wheels and it's about perfect to span the 3/4" PVC. The 3/4" PVC is like $4 for a 10' length x 2. I suppose you could spread the wheels as long as your bolt (axle) is long enough.

Yes! I had just thought of that last night. . .spreading the wheels along the axel 'til they fit. I'm using 3" bolts as the axels, so we'll see if it works.


What would be the advantage of a smaller pipe diameter vs. longer axel/greater distance between the wheels? If I have to buy new stuff, which should it be? Why? Only thing I can think of off hand is that a greater distance between wheels could make the dolly effectively wider, which would be a problem in some places.

Alright, well, spacing the wheels out aint' the answer; the axel flops around if the wheels aren't close enough together. I suppose I could lock it in place with more lock nuts, but it seems smaller pipe may just be easier.