Getting a dolly solid and steady - Give me your tips

[Ben Scott]

Hi all,

I have a Rigwheels passport dolly system, which I guess is not a million miles away from a Dana Dolly in operation.

But no matter how much I lock it all down and tighten everything up and throw sandbags on it I am still getting wobbles on moves.

At the moment I'm putting a Miller Compass 25 head on there with a Sony FS7 with mattebox/remote focus/Zeiss Otus/V-lock setup on there so sort of DSMC2 type weight.


Am using it with 30mm (1 1/4 inch), 3mm thick aluminium pipe 1.5m long. Should I use wider diameter or thickness?

I have some heavy duty Chinese Low Boy stands. These Kinosun ones

Are the Matthews equivalent absolutely solid when locked in or is there still some movement? Are their 'Slider stands' super solid and just as fit for purpose as their regular low boy stands? Benefits of each?

I've now swapped out the regular baby light stand adapters on the Rigwheels rail holders and put heavy duty 28mm/1-1/8" TV studs on there for more mass and surface area but it's not helped much.

How much extra sandbagged weight do you throw at it and how do you distribute that weight?


All tip and suggestions and advice gratefully received. I'm getting mighty annoyed at having to post-stabilise my dolly shots.

 

[ericyoung]

You kind of have to eliminate variables and pin down the root causes.

eg your second picture shows it without stands - so you've eliminated a couple of variables there - the stands' stability and the mounting interface. But it's on uneven ground. Put that same setup on a known flat surface like a hard countertop (check flatness with a steel rule), or use wedges and a spirit level to get the whole track level in both axis directions BEFORE loading up the dolly.

Check the roundness and straightness of the pipes by rolling them on a known flat surface, or just rotate them against each other checking for gaps that get bigger/smaller - ideally there should be zero gaps.

Check your pipes are truly parallel when mounted in their sleepers.

Check the dolly wheels rotate centred - ie no wobbly rotation indicating bent axles.

Check there are no permanent flat spots on the wheels - note if you have a heavy load on them and let them sit too long they can develop a temporary flat spot, in which case check for that and do a few rolls along the pipes to get rid of the flat spots.

Check the guide wheels are meeting the pipes evenly along the whole length of the pipes.

It could also be your own operating - jerky starts & stops, changes in speed, uneven/changing pressure, excessive pan/tilt friction, etc.

 

[Ben Scott]

Cheers Eric and good tips there. Much appreciated.


Wheels rotating nicely and no flat spots
Pipes new and perfect
My operating needs a fair bit of work but it's more that 'pat your head while rubbing your tummy' type needed for smooth tils+pans+dollies than anything else. The wobbles appear to come from elsewhere.

I'm veering towards blaming the stands purely because they are knock-offs, which is why I'd asked about how rock solid the Matthews stands are. However, as I could be completely wrong I don't really want to drop £600 on 2 stands to find myself in exactly the same position

 

[Jake Wilganowski]

Honestly the Dana kills the rigwheels for smoothness in my opinion. You look like your center of gravity is pretty high there on your camera, as well as long. As for the stands, the American grip Dana stands have a non-removable t-bar that eliminates all wobble:
http://www.filmtools.com/american-grip-dana-dolly-baby-combo-stand-rs00dd.html

 

[Ben Scott]

Thanks Jake, those aren't my photos. The centre of gravity isn't really any higher or lower than a Dana with the same payload.

And Dana Dollies are hard to come by in the UK so Rigwheels is what I have

 

[David Battistella]

Hey Ben,

consider this plate

http://www.floatcampro.com/store/low-profile-tilt-plate.html

lowers the center of gravity, still lets you pan a bit and will help reduce wobble by getting the weight of the camera close to the platform. Whenever you rain the center of gravity the weight can be shifted more easily and the will always create wobble.

David

 

[Ben Scott]

David that looks fantastic for several applications. Definitely one for the kit bag.

 

[Med D]

I have to think the wheels are a big part of the problem. Dana Dolly spreads the load over 16 wheels, the device you are using has only 4 load wheels. Also, the wheels are thin rollerblade wheels rather than the fat wheels DD uses. If the wheels have too much load per wheel, they are squeezed flat and will not roll as well. In fact I would not be surprised if they would permanently deform if loaded like the example shows.

If you are stuck with that dolly, you may want to look into high-durometer (harder) rollerblade wheels. That should be what they are using now but you could ask. These are readily available here in the US as "street wheels".

That photo also shows a very unrealistic load for that dolly. It looks like a DSLR dolly.

 

[Ben Scott]

Funnily enough on the Dana Dolly FAQ they make a point of saying their wheels are softer than skate wheels.

 

[Jake Wilganowski]

Dana wheels are like super soft gummy longboard wheels, I used the rigwheels recently and came to the same conclusion that they are made for light loads like dslr

 

[Ben Scott]

Ah well...


There's no UK dealer for Dana and no international shipping sadly.

 

[Phil Holland]

Funnily enough on the Dana Dolly FAQ they make a point of saying their wheels are softer than skate wheels.

This serves several purposes. The obvious being they help mask any imperfections/bumps on the track length. The additional thing that so many don't understand is that those softer wheels help also dampen operator induced vibration.

Not saying hard wheels aren't okay, but saying that the Dana Dolly is a smooth operator. Pretty much a fundamental tool to have on set.

 

[David Battistella]

Actually,

I like the rigwheels platform (really versatile) but I never baught their wheels. I just added my own softer longboard wheels. The platform itself needs to be longer to spread out the load over the track. Put another way the the Rigwheels wheelbase is a bit too short for heavier loads.

Ben, why not try inverting the whole thing and and hanging the camera off the track, the weight might be more to your advantage that way.

David

 

[Ben Scott]

This serves several purposes. The obvious being they help mask any imperfections/bumps on the track length. The additional thing that so many don't understand is that those softer wheels help also dampen operator induced vibration.

Not saying hard wheels aren't okay, but saying that the Dana Dolly is a smooth operator. Pretty much a fundamental tool to have on set.

Unless you're over this side of the pond

 

[Ben Scott]

Actually,

I like the rigwheels platform (really versatile) but I never baught their wheels. I just added my own softer longboard wheels. The platform itself needs to be longer to spread out the load over the track. Put another way the the Rigwheels wheelbase is a bit too short for heavier loads.

Ben, why not try inverting the whole thing and and hanging the camera off the track, the weight might be more to your advantage that way.

David

Would love to see the wheels you bought for it.

re inverting it, I'm only sticking an FS7 on it. No real big payloads.

 

[Med D]

I'm sticking to my thoughts re the wheels being the issue. If not the durometer then the contact area. I mean look at the difference. The cross-section of the Dana wheels is essentially square/flat -- the entire surface contacts the rail. Skate wheels are almost the opposite -- they are oval/pointy and have minimal contact area. Take those issues and throw in the difference in wheel count and I think you are looking at serious deformation of the wheels. There is a big difference between soft wheels soaking up a minor bump and soft wheels getting squished to a flat shape.

 

[Ben Scott]

To clarify, it's not bumping , it's wobbling,. The track is smooth and there's 8 points of contact. Hence me thinking it is the stands. Plenty of people have had wonderful results with it.

And again, I can't get a Dana Dolly over here so that's a no-go for me.

 

[Robert Hart]

I suspect you are on a hiding to nowhere with that amount of mass and its leverage of height over long spans ( 1.5M ) of thin gauge aluminium tubing. Four load-bearing wheels on each side instead of two would also certainly be better. Your arrangement has only two load bearing points of wheel contact to rails each side.

One tiny imperfection in the rolling surfaces jolts the balance ever so slightly, then springiness in the tube rails will amplify it. Adding support at two or more points between the end supports of the rail tubes may help. The roller arrangement causes a little difficulty in adding support to the rail tubes. Traditional finger wedges resting on wooden blocks at intervals under the tube rails may be helpful. They would need to run lengthwise with the tube rails to allow clearance for the vertical roller tyres to pass.

On a home-made piece of rubbish, I was moving a much heavier and taller mass on pieces of 30mm section angle-iron for rails, using automotive airconditioner idler pullies for wheels. Despite the imperfect finish on the rails and metal-to-metal contact, using four wheels each side virtually eliminated any tendency to bounce on imperfections. Four wheels each side also shares the bending loads upon the rails, again leading to less deflection and bounce.

You may also discover there is a very slight compliance in the pan pivot of that style of Miller head. If you are using the spring balanced pan-tilt function of the Miller head, the counter-spring force against the slight motions introduced by imperfection in the rolling motion may interact. You may find it awkard but possibly helpful, to set the camera rearward ( for tilt upwards ) or forward ( tilt downwards ) of the point of balance to keep the pan pivot of the Miller head constantly loaded in one direction rather than free to rock, albeit ever so slightly.

Locked tilt positions rather than dynamic tilt moves whilst dollying may also be helpful, though the tilt fluid friction upon a head left in free balance against the tilt spring tension may happen to have a beneficial dampening effect. This only applies if your spring-balanced tripod head is not overloaded. If the camera can tip forward or backwards all the way, then your tripod head is not of the correct weight class.

If you are using the rails and dolly elevated on lighting stands, then it may be helpful to add a vertical rod with a countermass. This should be equal to the weight carried by the dolly carriage including tripod head. The rod should be very rigidly attached to the dolly carriage and hanging down below it. It should not be springy or this will add to your problems rather than make them go away. As with noirmal best practice, movements should be applied to the dolly carriage at or as near as possible to the wheel attachment framework to eliminate any leverage or pendulum effect that a high push point introduces.

As with all my prognostications, treat with more qualification the comments of those more qualified than I in the audiovisual arts.

 

[Ben Scott]

Great tips there Robert.

I'm convinced the wheels aren't the problem but so many people have brought it up I would be mad not to give it proper attention, and I will certainly look at alternatives.

If anyone wants to sell me a Dana dolly and send it to the UK that would be grand

Or at least if anyone could recommend good set of wheels I might be able to order and affix that could be a good answer too.

Thanks again everyone.

EDIT: Have ordered some Matthews Slider stands, which I needed anyway but will update the thread on whether they help at all and on continuing efforts to get a perfect panning/tilting dolly move. Thanks again all.

 

[Ben Scott]

Stands have arrived. Instantly dialled out about 50% of the wobble I was experiencing. Not perfect but a night and day difference.

Have also rejigged the position of the wheels on the plate to drop the centre of gravity by about 1 inch, which also seems to help.

I see Rigwheels now offer a 'pro' version of the plate that will allow the head to sit a lot lower

Seems like that could do a much better job - and upgraded dana-style wheels would improve it further.

Thoughts? Aside from just get a Dana Dolly?