Dolly (pneumatic wheels not track)

[allana]

Hi,

I am going to be shooting some footage on streets etc where it's not going to be possible to lay down some track. I was wondering if anyone has built a dolly with pneumatic wheels and has any tips?

My initial thoughts are:
1: Two 7-ply boards sandwiched together for platform.
2: 4x fixed pneumatic wheels
3: some sort of bar to allow the grip to pull the dolly along.

I only need to dolly in a straight line, if need be I could buy two extra swivel wheels to replace on the dolly to allow some movement.

When shooting on a pavement (sidewalk) I'm worried I'm going to get bumps coming though. To prevent this I was going to deflate the tyres a bit, obviously this makes steering tough but as I said I'm using fixed wheels so we're going in a straight line.

So any thoughts? Any experience? Anyone know of anyone that has built a DIY dolly with pneumatic wheels?

[fredrickkinsman]

As strange as it sounds try out a landscape cart they have inflatable tires,let out a little air and it absorbes some of the vibration.i bought one for one hundred dollars and it has a steel frame and a dump bucket,which you can sit in and hold the cam or mount the cam in it or even remove the bucket and lay down a peice of ply wood on top.its pretty good about the same as the old wheelchair dolly.try walmart or home cheapo.

[scotthampton]

I think you're going to run into some trouble with such a setup. Are you certain that you can't use a track, even a DIY track? I tried a similar setup and had to promptly return it. ANY bump or cook in the road is going to travel up the path and hit the camera, affecting your footage.

I just finished my DIY dolly and will be testing it out really soon.

Where are you shooting, and when? Are you certain that a dolly is the correct mechanism to achieve the shot? What about a handheld stabilizer?

[allana]

I live in the UK so buying anything bulky from the US is out of the question.

Tracks are definitely out of the question. Otherwise I think the Indie Dolly is a very cost effective solution.

I had a thought about dampening the bumps on top of a bit of tyre deflation.

Each castor would be joined to the tripod platform by four bolts. What I could do is use extra long bolts and place a spring in between the castor and the platform. Each bolt would have it's own spring 4 for each castor and in total 16 for all four castors, so the weight would be split out evenly.

I still have to figure out how to reduce wobble as the castors should only be limited to moving up and down, not left and right. This could possible be accomplished with a fixed center pole running through the tripod platform but not fixed to the platform. Or possibly some very short springs might reduce the bumps without introducing wobble. Ideally some leaf springs would work in this case, but not sure if I could source some cheap small leaf springs for my purpose.

I have found someone else playing around with pneumatic dolly:
http://dvxuser.com/V6/showthread.php?t=147246

I found the Creeper Stool he is using on ebay for £15 a worthy addition to the dolly.

A

[scotthampton]

OK, I understand, but an outfit like that is huge... I thought about what I'm doing now: have a short length of track that can be easily transported. I have 4 feet of track that goes over a short distance. Roll it the distance, pick it up, and move on. But, again, where are you shooting, and when? Are you certain that a dolly is the correct mechanism to achieve the shot? What about a handheld stabilizer?

[allana]

Scott, I've tried a few stabilizers and was not impressed with them. Only an experienced steadicam operator with a high-end steadicam can get decent results otherwise everything we have tried looks a bit amateurish.

[allana]

This is a rough sketch of what I mean with the springs:
http://i42.tinypic.com/adgfhs.png

[fredrickkinsman]

What your describing may work ,but the other thing to think about is noise,is it going to be quiet enough ,and are you using a boom pole for the sound from a distance?

[fredrickkinsman]

The actual bolts themselves would have to be able to flex,if you put a spring on the outside of a bolt its not gonna move unless the bolt is spring loaded,does this make any sense,sorry if im sounding confusing

[CycleWriter]

This is a rough sketch of what I mean with the springs:
http://i42.tinypic.com/adgfhs.png

Here's what's wrong with your setup. With the springs over the bolts the only way for them to absorb impact effectively is if they move in unison. Since the pivot point of the wheel is off center of the caster base, that is next to impossible. Greater impact force will always go to the two mounting points closest to the wheel axle. That will make the caster flex rather than compress and the springs will bind on the bolt shafts.

[DSvideo]

I did a shot outside on an exposed aggregate sidewalk...quite rough. I used a doorway dolly. I used a tripod on the dolly for one take, then I tried holding a fig rig while I sat on the dolly. Fig rig worked MUCH better and as long as you have a fairly steady hand then you can keep it looking very good. I ended up using the tripod shot though because I had to zoom in and out which I found to be difficult on the fig rig at longer focal lengths.

Try the landscape cart and a fig rig. Then apply the smoothcam filter in FCP or whatever steady shot app you have access to.

[allana]

@fred, yes there would have to be springs on the other side of the platform to and the bolts would have to be pre-tightened. Sound will be recorded with a boom independantly.

@cycle, correct that's why a leaf spring would help if mounted correctly it could limit the movement of the castor.

Regarding stabilisers etc pulling focus on one is terribly difficult, unless you're using a remote. Even sitting on a dolly doing this probably won't help get a rock steady shot.

I think I'm going to have to consult a mechanical engineer before I get someone to build this.

[MAGICOFPYRO]

how about this?

http://bp1.blogger.com/_IOr751U0Yag/RoBVc-a4ZPI/AAAAAAAAAJ0/VFJYG5rCxcM/s400/Steadicam.JPG

[allana]

@Magic, do you know if this is a custom build or a commercial product... I'd love to see a better quality image of it.

[allana]

Matthews RED dolly, doesn't seem to have much of a solution other than have your steadicam operator stand on the dolly... their overhead dolly stabiliser doesn't look at all stable.
http://www.msegrip.com/mse.php?show=article&cat=11&ID=278

[Erik Bien]

There's always the Segway Steadicam:
YouTube - segway steadycam

Seriously though, the "studio wheels" on a Matthews Doorway Dolly (http://www.msegrip.com/mse.php?show=product&cat=422&products_ID=26251) aren't too different from your inflatable-tire garden cart. One trick for dollying on unfriendly terrain is to lay down a 'dance floor' of say 3/4" plywood topped with masonite (hardboard).

[allana]

The problem with laying down a dancefloor is the same as the track, we're not afforded that luxury in this situation.

[MAGICOFPYRO]

@Magic, do you know if this is a custom build or a commercial product... I'd love to see a better quality image of it.

just a picture I found while browsing the net, it looks like those front tires are designed to absorb a lot of the unsteadiness of the road!.