Slider width?

G

ggrantly

Veteran
Hello Listers,

I am finishing a long stalled project to build a 12' slider track made from 1.25 (1.625" OD) sch40 aluminum pipe with speedrail fittings on the ends. Is there a standard width for the tracks? Obviously I could make this any width I prefer, but am curious if there is any industry standard for the typical roller car. I may end up with multiple spacing options since I have wheels for my tripods also, but I'll address that separately.

TIA
Grant
 
I made one up with schedule 80 pipe just to get more stiffness over a 10' span. I don't need a center support. Dana is the standard. I don't recall how I came up with my width of 12-1/4" O.C. for the pipes, but I know I spent a lot of time trying to figure out what Dana used and maybe that's it.

Here is a video of mine - https://www.youtube.com/watch?v=1H_duxFmvlw

Don't waste your time fabricating your own wheel sets from skate board wheels. I was going to go that way, but this set of wheels is excellent. The wheels themselves are perfectly true to less than .001" runout, which is something Dana likes to brag about. They are very well made. https://www.ebay.com/itm/Glide-Gear...:SpwAAOSw0A9aIDzR:sc:USPSPriority!94952!US!-1



Pipes are stored in pipe insulation foam to keep them nick free.





 
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I've used the Dana Dolly a lot, my producing partner has one. If you want larger moves with heavier cameras, it's the standard before you go to a real dolly like a Fisher 11. If you like to use tiny, lightweight cameras,
I'd look at Rhino or Kessler over a Dana. Dana Dollies, If you have a small or normal sized car, are a PITA to transport. Not the dolly itself but the speed rail of any decent length and my partner has Matthews Heavy Duty low rollers which
make it super easy to move once set up but are a PITA to transport. The setup shown above probably works great but will take two or three people to move it once set up since it's on stationary stands.
 
Yep, and the stands I have are the wrong ones. Light stands aren't strong enough to be stable for the Dana. It worked for the shots I built it for, but I wouldn't use them on a regular basis. You really need something like the American Grip Dana Dolly Baby Combo Stand - https://www.filmtools.com/american-grip-dana-dolly-baby-combo-stand-rs00dd.html.

Edit - I didn't see what drift recommended. That looks a lot nicer than the American Grip stands.
 
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Thanks for the input.

I have a set of kessler trucks which are premium quality. I haven't decided on my dolly design yet, but fear not, in my past life I owned a machine shop and made some of my living designing and fabricating custom yacht hardware.

For full length 12ft runs on sch40 pipe, I'll be using 4 c-stands for support, or a heavy tripod with 2 c-stands on the opposite ends.

If transport became an issue, the 12ft sections could be cut in half and spliced in the field with an internal sleave. If you take 1" sch80 pipe and turn about .050" off the OD, it makes a nice internal sleave. A 24" length would give 12" in each half, and should be plenty strong for 10-15lbs.

Mostly I was concerned if there was am industry standard centerline measure.

Grant
 
ggrantly said:
... If you take 1" sch80 pipe and turn about .050" off the OD, it makes a nice internal sleave. A 24" length would give 12" in each half, and should be plenty strong for 10-15lbs.
Click to expand...

That sounds good. I've been wondering what to do about a splice to cut mine in half. Even though I have a van, as drift said, the long pipes are cumbersome. Cutting them down to 5' lengths would really help packing/handling.
 
Paul, a few things. If the pipe you have is welded, there will be a pretty large seam inside which will be problematic for a good fit by the sleave. Extruded pipe will have no seam to interfere. Also, when measuring, do both the pipe and sleave in two directions as both might be out of round by plenty enough to measure. Any shop that has a lathe should be able to make a nice slip fit pretty quickly. Likely a half hour to turn two sleaves. It can be hard to find anyone who will care about a job this small. You might want to take the pipe in for them to check the fit if you're not familiar with precision instruments. If your pipe has seams, it could be bored to a depth of about 6" but this would require enough time that you may want to re-purchase your pipe depending on how you source such things. I would add a set screw of some sort on one side, at least, and probably both.

Regards, G
 
24.5 in is the 'standard' check some grip shops.

Personally I want a bit wider as I found some issues with being able to flip (to do underslung) with my trolley which is made from a Prolye base plate (and also attached to Prolyte equipment therefore)

S
 
Paul F said:
Yep, and the stands I have are the wrong ones. Light stands aren't strong enough to be stable for the Dana. It worked for the shots I built it for, but I wouldn't use them on a regular basis. You really need something like the American Grip Dana Dolly Baby Combo Stand - https://www.filmtools.com/american-grip-dana-dolly-baby-combo-stand-rs00dd.html.

Edit - I didn't see what drift recommended. That looks a lot nicer than the American Grip stands.
Click to expand...

I have a set of the American Grip Dana Dolly Baby Combo Stands. Purpose built but klunky especially to store. Great if you have a Grip Truck. Dana gives you great moves but most of the time I use a small slider from an iFootage Shark S1 bundle kit with a ballhead and a mirrorless camera. The convience in almost all applications for me far outweighs pulling out the Dana with all the attendent gear and the risk of wrecking your big camera.
 
30cm matches what I made.

G, My lathe has just enough of a bore through the headstock to accommodate the pipe, so I'm good there, but I don't have a boring bar that long. So I have an excuse to buy another tool. :smile:

I'm no machinist. What kind of clearance do you suggest? I.e., if I bored it out to 1.290, what should the sleeve be? I'm just thinking that aluminum likes to gall, so I don't want it to be too tight of a tolerance.
 
Paul
A couple of notes on my 'track' journey.

Ive been recently working with a proper machinist.. he hates going aluminium to aluminium for such uses. Id go with steel or brass for inserts.

Overall I think making track joins is very hard (having tried a lot on my Boxford). The pipe is probably highly inconsistent for both size and concentricity. Skimming the tubes out is a good plan.

Id go with single sections I have 2.4m (goes in my van) and 3.5m (goes on my van roof) yes I use the scaff foam.. brilliant!

Ive rented proper track and it wasnt that good (at 100mm) - I think using skate wheels has a limit.. basically the smaller the wheel the better the track joins have to be.. big heavy dollies with 150mm wheels allow a lot more give in the track joins. Another good wheel design is the 'see saw' of two small wheels on a central axle - it allows more give than dana hard wheel pairs.

I think a big sucess of the dana design is to limit the track to simple tubes and know its limitations in terms of travel.

If you must have a buildable system lengthwise something like http://www.solidgripsystems.eu/products2/twindolly/twintube/ is it but very expensive.

As for mounting.. I use two sachtler tripods and have bowls on my end sections - easier to level than light stands.
 
Good notes Morgan - The problems with joints you are pointing out is exactly why I haven't done it. Plus not really knowing what might work for a joining mechanism. I've got sleeves on my 16' tubular jib, but it doesn't care about mismatch or slight bends at the joint. I made them plenty loose to prevent galling. G's setscrew idea would solve the bend problem.

morgan_moore said:
... The pipe is probably highly inconsistent for both size and concentricity. Skimming the tubes out is a good plan.
Click to expand...

Ok, this I hadn't thought of. I would then mark the pipe with an indexing mark before I cut it so it can be lined up when using sleeves. I could true it up with the lathe, but I'd try the indexing first.

morgan_moore said:
Ive rented proper track and it wasnt that good (at 100mm) - I think using skate wheels has a limit.. basically the smaller the wheel the better the track joins have to be.. big heavy dollies with 150mm wheels allow a lot more give in the track joins. Another good wheel design is the 'see saw' of two small wheels on a central axle - it allows more give than dana hard wheel pairs.
Click to expand...

Yes, I spent a lot of time block sanding the pipes to get them smooth and nick free.

morgan_moore said:
I think a big success of the dana design is to limit the track to simple tubes and know its limitations in terms of travel.
Click to expand...

Yep, past 10' or so and it's time to use something else. I only want the joint to shorten the 10' pipe for storage in the van. It's a pretty low priority, but I might give it a go when there is time.

morgan_moore said:
As for mounting.. I use two sachtler tripods and have bowls on my end sections - easier to level than light stands.
Click to expand...

Thanks for the reminder. I forgot about that option. I was thinking about that when making the pipe supports, but I needed the dolly quickly and ran out of time to come up with a mounting system for tripods.
 
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