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-   -   Tennis Balls ... (https://www.dvinfo.net/forum/dolly-track-cable/47369-tennis-balls.html)

Riley Harmon July 8th, 2005 01:44 AM

Tennis Balls ...
 
Has anyone heard of setting up 2 tennis balls for each corner of a skateboard dolly instead of using skateboard wheels?? A friend of mine told me he remembered reading an article in VideoMaker about it. Kind of like older folks have tennis balls on their walkers...has anyone heard of this/experienced it?

I believe its for a one man dolly...only the camera and tripod would go on the platform...?

Rob Lohman July 12th, 2005 03:43 AM

I can imagine this could work, however I've never heard of seen it as of yet.

If you have a "skateboard" dolly perhaps you could try it out?

Riley Harmon July 12th, 2005 04:02 PM

I just hooked up the tennis ball dolly and oh man does it ride oh so smooth. Great thing is it's so lightweight. I'm about to take some test footage and pictures...stay tuned!

Riley Harmon July 12th, 2005 07:45 PM

http://www.rch-e.com/temp/t-cell.jpg

Here's the tennis ball dolly.


Here's some test footage:

http://www.rch-e.com/temp/dolly-test.mov

total price including track= 20 dollars

Patrick Jenkins July 12th, 2005 08:27 PM

I'm confused. Could you post a pic of the underside? How do you keep the balls from 'frictioning' against the frame? How does the thing move?

Riley Harmon July 12th, 2005 08:42 PM

it works the same as a skateboard dolly, the tennis balls are mounted by a vertical bolt, the balls sit side by side making a V similar to skateboard wheels, the 3/4 " electrical conduit fits in the V groove and slides..
sorry if that pic was confusing, the dolly isnt actually on the track in that pic

Patrick King July 12th, 2005 09:03 PM

Will the tennis balls slide as easily as smoothly on PVC for track?

How about a stiff industrial water hose?

Barry Gribble July 12th, 2005 09:11 PM

Riley,

That is really smooth, nice job. Yeah, it would all make a bit more sense to me if you had a shot of the rig on the track, or better yet a video of the dolly in action.

So the tennis balls are just sliding on the track? How much weight do you have on it (cam + tripod + rig)?

The video shows a bit what I would expect of the motion - a rough start, but then smooth motion. It's tough to get that first bit of movement?

Keep it up and show us more.

Patrick Jenkins July 12th, 2005 09:18 PM

Very cool!! Hell of a lot cheaper than going out and buying roller blade wheels as well!

Riley Harmon July 12th, 2005 11:36 PM

Dolly Demo....

http://www.rch-e.com/temp/DollyDemo.mov

Pre Answers to questions:
*the bungie cord is used to pull the tripod tight against the dolly sled/"platfrom" so that tripod and camera dont fly off

*weighs about 5 pounds or less

*in theory would hold camera weight up to about 20lbs before the tennis balls start to sag in, definately a one man dolly, all you have to do is push the tripod

*disassembles for easy transport

Patrick Jenkins July 13th, 2005 07:12 AM

Thanks for that! I was figuring they roll or something..

Dan Selakovich July 13th, 2005 08:22 AM

Oh, good lord. Now that's just freaky. I'm wondering how many moves you can do before the fuzz starts coming off the ball making it not so smooth any more. Keep us updated!

Dan
www.DVcameraRigs.com

Barry Gribble July 13th, 2005 11:45 AM

Riley,

Good job - can't be much more clear than that.

Last questions:

1. The electrical tubing you use... how long can you get that?

2. Do you drill through the tennis balls first? Does the bolt just go through one side of the tennis ball, or all the way through?

Thanks for sharing.

Riley Harmon July 13th, 2005 12:29 PM

The conduit comes in varying lengths. I bought a 10 ft section of 3/4" EMT for 5 bucks each. As far as the bolt. I took a knife and made a small hole on both sides and then popped the bolt all the way through.

And if the balls get worn down, they are cheap enough to replace. I paid $.94 for a 3 pack and got 2 packs for 6 balls total.

Patrick Jenkins July 13th, 2005 01:16 PM

Would PVC work well for the rails? PVC can be joined pretty easily with those screw in nipples (watch it! ;p) without bumps. Not sure if conduit can do the same (you could always wrap the seem in tape I bet..). PVC is also cheaper than conduit and you can arc it to make curving track.

Riley Harmon July 13th, 2005 02:14 PM

conduit you take dowel rods and use them to link sections together, i imagine it would glide just as smooth on pvc as long as the pipe is clean and no gunk

Shawn Redford July 17th, 2005 02:05 AM

Thanks for posting all the photos and video Riley - this is a great low cost design.

Richard Alvarez July 17th, 2005 03:49 AM

Nicely done Riley, a good variation on a friction dolly. Puts me in mind of the "Vaseline sled" Raimi used in the first "evil dead" flick. He took a sixteen foot 2x12 and set it on saw horses. Mounted his camera head to another short piece of 2x12 that had jigs cut to keep it centered on the 'rail'. Greased the board up liberally with vaseline, and just slid the thing along a track.

Necessity IS the mother of all invention... And an empty wallet is the father.

Jim Parks July 17th, 2005 07:28 AM

RE: Tennis ball dolly
 
Riley:

Thanks for posting the videos and photo. Good job! I think I'll try putting one together!

Jim

Timothy D. Allen December 28th, 2006 08:59 PM

Hmmm... I guess I found this post too late. All the links are broken. Bummer, too.

I was really interested in seeing how this all looked. :-P


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