Dolly Help!!!!!!!

F

Fxguy

Member
Ok guys, I finally have been convinced to switch over!!! I was a long time XL-1 user and have been dying to buy another camera to shoot some stuff, but after checking out this forum, I have decided to get the DVX100a to shoot with!!


Anyways, I have just spent a fortune!!! on building a dolly. My platform setup seems to be ok, but I am using 1-1/2" conduit pipe for the track and the platform keeps slipping of the track and the pipe keeps rolling on a concrete surfaces. I have thought to put a threaded rod through the side and lock it with nuts to keep it properly spaced, but any suggestions? I used inline skate wheels , should I have used regular, more square wheels?



Please help so I can get awesome shots that are super smooth!!!!


I will post pics in the next day or so when I can get some time.



Thanks
Fxguy
Tim
 
Pics

Pics

OK, Finally found the photo hosting site and had time to take pics this morning before work. Here they are:

I spent around $129 on the platform, track, and all hardware, plus $39 for the in-line wheels with Abec-5 bearings.

PARTS
Parts.jpg


Pull Bar
PullBar.jpg


Platform
Platform.jpg


Wheels
Wheels.jpg


Wheels on Track
WheelsonTrack.jpg


Completed So Far
PlatformonTrack.jpg



Cant say I am exactly handy with this sort of thing. I am taking a precision machine tooling class this fall to give me access to more equipment than just a drill press and also enable me to bulid a steadicam using cody deegans plans.

Anyways, any help will be appreciated. All I can figure is either change the wheels, change the track, or bolt the track together on the sides using threaded rod and some lock nuts.

Fxguy
Tim
 
Re: Dolly Help

Re: Dolly Help

Yeah the Steel Angle Bent when one of the track rods rolled out from underneath the dolly when a friend was trying it out. As far as the 2X4 between the platform and the angle, its because the inline wheels are too big and touch the wood if there is not a spacer there. I am going to try skateboard wheels instead of inline, since the conduit is 1-1/2" in diamter, the skateboard wheels will allow a better size of track and to keep it from rolling I am going to try threaded rod perpendicular to the track and bolted in the sides of the track. Still, as it is right now I get smooth shots, I just can ride on it or put any weight on it. Plus the track isnt connected together as well as I would like, its just friction fitted, and I am buying some Hoellender fittings to screw the connections together better.
 
2X 4's

2X 4's

Well, as for an update, I returned the in-line wheels to sportmart for an even exchange for skateboard wheels. Put those on and I think you guys are right, I need a smaller piece of wood. The skateboard wheels are much lower profile, but they still slightly bump the platform, I am going to Home-Depot tomorrow and replacing the bent angle, and getting some 1x4 or 1x2 to put between the angle and the platform. All in all, even with the bent angle, its a smooth ride and with the skateboard wheels, the conduit doesnt deviate at all.

I am still going to work on the track a bit, bolting it apart with a threaded rod spacer and filing down the joints. I like the idea of conduit because its much stronger than PVC. If there was a lot of space under a PVC track, do you guys think it would hold up?

Also any suggestions on Track diameter? I feel that at 1-1/2" my track is a bit larger than most i've seen on here. And a little expensive too, at 16.50 per 10' tube, it costs me 16.50 for evey 5' of track I want to add.
 
1" track would suit you fine. but the larger diameter is nice cause itkeeps the dolly further off the ground and potential bumps that would reach the wheels .. like grass blades.. they really mess up a dollys' ride. the PVC will not hold up over a gap underneath.. not even thick walled pressure pvc, but if you buy only a couple aluminum or steel rods to insert in it with the same outside diameter as the inside diameter of the pvc.. (1" interior thin walled pvc fits 1" exterior metal pipe. as should be expected) you can insert the pipe into the pvc and place that reinforced heavier section just over the gap you want to bridge. and the thin walled pvc is the same diameter as the thick walled pvc on the outside. so you can still join them together at the ends and switch back to thick walled PVC once your over the gap. that way you only need to carry with you a couple heavier metal sections, and mostly you can just carry PVC.
 
The problem with conduit is that it is very difficult to connect two pieces without getting a little bump at the joint when you dolly across it. You can mount the PVC to lumber to avoid the dips, and pvc is easy to join so you don't get that bump. For the wheel assembly design in my book, I use 3/4" pvc, but am unsure what you'll need for your wheel layout.

Dan
www.DVcameraRigs.com
 
wouldnt 8 pairs of wheels be better than 4 pairs of wheels.. that way, when the leading set of wheels, goes over a 'dip' in the pipe, the other 6 pairs are still on 'solid' pipe, holding the dolly up. Having only front and rear wheels means the front dips down when the wheels hit an imperfection. Imagine a motorcycle's front wheel hitting a pothole vs an 18 wheeler's front tires hitting a pothole (not a perfect analogy but you know what I mean)
 
..yes, more wheels is better. and of course .. better wheels are better. ...allowing for smoother transitions for exactly why you mentioned, and also allowing more more weight on the dolly and more even distribution of the weight underneath the dolly. .. for the similar reason that more wheels over a track connection is better.. more wheels when you hit an imperfection on the track is better.. imagine you only have 2 wheels on each corner. you have 4 connection points to the track..one for each 2 wheels. so if weight is centered on the dolly.. each connection would hold 1/4 of the weight. so lets say you run on 6 wheels per corner. if we consider each set of 2 wheels as a "connection".. you would then have '12 connections"..each of them taking 1/12th of the weight. .. so now.. imagine you have 4 legs to stand on and one of them trips.. now imagine you weigh the same but have 12 legs.. and one trips.. it would affect you far less. because not as much weight would be on that leg/connection. and it would be more easily compensated for by the rest of the stable legs/connections.

having more than 2 wheels per corner also allows you to offset the wheels. offseting the wheels helps track transitions as well. instead of having one conection of pair of wheels hit the track connection both wheels at once causing a dip or bump, the wheels will change over the connection with an unnoticeable transfer of weight from one side to the other . because the front wheel in the offset will go over first, and then the the dolly continues until the back offset wheel on the other side goes over. ..this allows the back wheel to try to hold the dolly on the last section of track longer until the front wheel is smoothly on the next section.. similar to having more sets of wheels to help the transitions. of course having multiple sets of offset wheels is great. I just had a corporate shoot this last Sun with close to 450 lbs of people and stuffs on a 6 offset wheel per corner dolly over 30 feet of track with 2 track connections in the 30' length on surfaces from marble and granite to plush carpet. we went slow as molasses...all the way to running speed. sturdy as a mountain.. smooth as glass. my suggestion wouldbe to throw at least 2 more wheels per corner on there, and offset them.
 
Iamloser,

Can you provide a picture showing the method of joining the two pvc pipes together using a metal pipe or rod? My dolly setup is perfect except for the bump I get when the wheels cross over the joined edges of the pvc pipes. Thanks.

Dave
 
DeeJco1 said:
Iamloser,

Can you provide a picture showing the method of joining the two pvc pipes together using a metal pipe or rod? My dolly setup is perfect except for the bump I get when the wheels cross over the joined edges of the pvc pipes. Thanks.

Dave
Click to expand...

..currently i use a screw in track connector setup. the track simply screws together tightly with a few twists of the wrist. i had a pic of it in an old thread.. ill try to get one up for you tonight or tommorow. I include sets of the screw in connectors with a "thread tap cap" for 1" thick walled pvc with my dolly wheel sets.
 
If you are using a thick walled 3/4" PVC, get yourself a 1/2 steel pluming nipple about 1" long. The nipple will be threaded all the way on the outside. Screw this into the pvc halfway: the first time you do this, it will be difficult, but you are basically making threads in the pvc as you screw it in. Take your 2nd length of pvc and screw that onto the other end of the nipple until the 2 pieces are secure. It holds extremely well, makes a great seal, and no bump when the wheels go over it. Here's a hint if you have trouble screwing in the nipple: heat it up before screwing it in. It will melt the pvc a bit, and go in like butter.

Dan
www.DVcameraRigs.com
 
..thats the same thing i use, but i use 3/4 " for 1" pvc, and a capping nipple to make the threads.. you just put a wrench on the end cap and screw in the cap a few times in and out being sure to go straight.. then you use the couplers to join the tracks end to end. ive whipped around a 30' length of track joined like this , and it holds like one peice.
 
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