Built A Home Made Dolly... Help!!!!

STORYTELLER32

STORYTELLER32

Well-known member
Ok, so I'm sitting here pulling my hair out of my head. I spent the time and money to build a dolly, using two 3/4 pieces of plywood bolted together. I've got it on 16 skateboard wheels (ripped off of some el-cheapo skateboards purchased at WallMart) running on 1 &1/4 inch PVC pipe.

So what's the problem? BOUNCING IMAGERY!!! I'm SO annoyed... Granted I only tested it with a canon elura (really light weight cam) but would that make such a difference? Does anyone else have the problems I'm having? I find the PVC pipe picks up all kinds of dust and dirt (as do the wheels). Is it the cheap wheels?

Suggestions are needed, please help.
 
Assuming your track is on a reasonably flat, hard surface you probably need more weight on the dolly. Try riding with it if you haven't already. You should be able to get super smooth moves. The longer the focal length, the more challenging it will be to get smooth looking stuff. Full wide will look like glass.

There's lots of static electricity with the PVC. It should have little to no affect on the smoothness. The wheels might even get squeeky. Try wiping the track down with Endust or Pledge. Also, if the PVC is too small in diameter it will flex too much on soft/rough surfaces.
 
Hey, sotryteller, it's a common problem. In fact, I haven't seen a production where at least some shots were'nt called by the DP as 'dolly bounced' - even with big, heavy dollies and 35mm cams on metal rails, it does happen.

Try to spray or wipe the PVC pipes with antistatic spray/wipe. I use the type used to wipe LCD monitors, and it helps a bit.

The dolly itself may not be heavy and sturdy enough - wood bounces, as musicians know :shocked: . I reinforced mine with steel strips, but found that putting something heavy on it (sandbags or bricks) makes it better.

The lighter the camera, the heavier the tripod needs to be. So, if you are using a tiny cam, try to get the most robust tripod you can get. Rental places have pretty solid video tripod for something like $10/day. You may also want to hang something heavy between the legs (of the tripod, not yours, you pervert! :grin: ) - that further decreases vibrations.

As far as the wheels - keep them clean, same method like the PVC pipes.

Try to use wider shots - the longer the focal length, the more any vibrations will be noticeable. I know this goes against Barry's DVX book (Z99, F/2.0), but you have to find a compromise somewhere...

Good luck!
 
Hey Storyteller I built a similar dolly. You can see it here:

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

Cheap wheels might be a problem, but I'm not sure how big a difference it would make. You definitely need to keep your track clean.

Now, in addition to everything XCzech said, I found that while PVC pipe works reasonably well, steel pipe is the bomb. PVC pipe will flex a little, even with weight on it (sometimes more so). But steel pipe from home depot seems to give the most solid ride.

Best of luck to you.

Matt
 
Also I think you need more wheels. If you look at mine, I added a set in the middle as well and mounted them on steel brackets that run the length of the dolly to reinforce it.

Matt
 
Thanks for the tips guys. I lifted my dolly up and spun the wheels by hand. I noticed they're not perfectly in round. Some spin close to a nice circle, but others are a slightly oval in their movement. Does everyone else have this as well? Or am I just using crappy wheels? I seem to be getting repetitive bumps at regular intervals so I'm wondering if that could be the problem. If it is, where did everyone else get their wheels? I went into a sporting goods store and found brand new ones for like $100.00 so I opted for the wallmart option.

Also, what size PVC is everyone else using? I followed Joren Clark's directions ( http://www.jorenclark.com/whitepapers/dolly.html ) and he uses 1 & 1/4 inch so that's what I got.

Thanks in advance.
 
I spent about $100 on decent rollerblade wheels with bearings - they run perfectly. If your wheels are that bad then that's DEFINITELY the first thing you need to address...

I'm pretty sure I'm using 11/4" pipe as well.

Matt
 
Hey Matt, thanks for the info. Your dolly looks great! I used angled aluminum for mine so I thought I'd have to use skateboard wheels. But now I'm wondering if I should go buy some cheap rollerblades from Target or something instead.

I noticed your wheels are straight up and down on the track. Do you think the narrow point of the rollerblade wheels would be an issue on an angle?
 
ST, Thanks. I don't really know how the rollerblade wheels would work on an angle but I thought the would work better vertically. You can see in the pictures how the curve of the wheels match the curve of the pipe, this makes for a pretty smooth ride, plus, if you have a smooth floor, you can roll it pretty straight without the pipe. Bear in mind, if you mount them vertically (or on an angle for that matter) you'll need different size angle iron for the clearance. I used garage door pieces from home depot that were pre-drilled.

Do yourself a favor though, invest in a decent set of wheels. You can get all the wheels you need from Sports Authority for under a C-Note (it's not so much the wheel as it is the bearings, me thinks).

Matt
 
Well, this is going to be a costly learning lesson for me. I spent $50.00 on the angled aluminum alone and I can't return it because I drilled holes in them. At least I kept the skateboard receipt's.

So what's the better way to go? Purchase brand new wheels for around $100.00? Or buy rollerblade wheels and change out the angled aluminum for the garage door iron? Seems like either way I'm looking at another $100.00 spent. Decisions, decisions....
 
I'd probably spend the $100 on good skateboard wheels. While I like my design, the one you're working with has been well proven, you just need better parts. Also, I would add a set of wheels in the middle of the dolly, especially if you plan to put an operator on there.

Matt
 
Cheap wheels are cheap for a reason. I have found that for these types of dollys, it really helps to have a very sturdy platform with a lot of weight on it. I use water weights. They are easy to carry and do not take up a lot of space in my kit.
 
Yeah I think you're right Matt. I'll have to bite the bullet and purchase perfect wheels. But I'm going to hold off on adding an extra set of middle wheels until I see the results from the change out. I didn't create 4 smaller angle segments at the corners like most people do. I have the angled aluminum running the entire length of the dolly so it's pretty sturdy. But if I drill another set of holes, I have to make sure to line them up perfectly with the others or I'll get a pivot in the center (which would suck!).

I'll let you know how things work out.

Thanks to all who responded. If others have other suggestions, please post 'em!

PS: Rosestar, are those water weights refillable? As in I can bring them to a shoot empty and fill them on location? If so, where did you get them?
 
I built one like yours, with the angled aluminum. I bought a pair of roller skates at a thrift store for $5 and the wheels work fine for me. It sounds like you got a bad wheel or something. If you can see it moving out of place when you spin it then something is definitely not right with it. Take them back and check out the wheels on some other skateboards before you drop $100 needlessly. Just my 2 cents.
 
THe one I builkt is like Matt's with the perpendicular wheels. If I had to do it again, and I'm sure I will, I'd use skateboard wheels and put them perpendicular to each other. That seems to be what the pro rigs do. It keeps the dolly from slipping off the track.

I use 1/2 PVC because it's more flexible.. I like that I can put a slight curve in it, and the dolly will follow. It's also great to go down a hill. You get that "Hey I'm at the top of the rollercoaster" effect when you mount the cam right to the dolly

I'd also follow fuboy's advice and check out the thrift store. The ones around here of tons of rollerblades and traditional rollerskates.
 
VJ, why would you put skateboard wheels perpendicular? It seems that most of the wheel would not be in contact with the track that way?

Matt
 
I went to Target yesterday to check out some kiddie rollerblades. They were selling them at $10.00 a pair. Problem is when I opened the box to check out the wheels, they too weren't perfectly in round. My guess is the really cheap stuff is cheap because of the imperfections in the bearings.

Went to a sporting good store yesterday and bought brand new rollerblade wheels with new bearings. A set of 8 were $40.00 so I had to buy two sets. Then I get them home only to find out they're too big in diameter for my dolly. They'd rub up against my dolly platform... OY!

Ok, so I'm driving two towns over tomorrow to the only real skateboard shop in my area. I'm told they have wheels galore. More later-
 
I use 72mm Rollerblade wheels on my dolly. And i'm very happy with them. I think they are just marginally softer than sketboard wheels which makes for a smoother ride.

Pictures are at: http://mikko.n3.net/photos/

The dolly base is an old HEAVY table, with flat Iron bolted to the bottom that space out a full length aluminun Angle"iorn"s at 62cm (standard width).
It hase 2 wheels in each corner only. - I'm thinking of adding to 4 in each corner to smooth out the joints. - My track connections arn't that great.
My track is 30mm diamiter Aluminum pipe, cut to 1.5 lengthes and fastened at 62cm guage. - The track sections can fold for easy portability.

- Mikko
 
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