Lightening tripods
 

I have a Uniloc 1600 tripod. It's a marvelous piece of kit, and very stable. But heavy especially when carried several miles across the countryside. I've looked for alternatives and can't find anything that comes close in terms of versatility.

So I've looked into replacing the legs with carbon fibre ones, and the price of carbon fibre tubes is prohibitive. It'd be cheaper to cannibalise a new carbon fibre tripod or even better a used one.

Anyway, I wondered about drilling holes in the Uniloc's duralumin legs. It'd look odd, but I wonder if drilling a series of holes along each leg would lighten the weight without a significant impact on the rigidity? Has anyone tried this? Is it worth it, or do you have to remove too much metal. Or would it impact the rigidity too much?

Leif,

This is a quick call in on the forum so have not made any calculations based on wall thickness.

I have just weighed a length of aluminium 270mm long, 19mm dia, = 200 grams.

To shave any significant weight of by drilling holes suggests an awful lot of holes. I would not think that option to be a runner.

Don

Have to agree with Don on this one, in order to reduce the weight by an amount you would notice, you'd have to drill a lot of holes. Drilling one hole in a piece of metal seriously affects it's rigidity, drilling so may to reduce weight is a non-starter I'd say.

Duncan

Now there’s an interesting concept which is certainly used through industry for the same benefit. Something you could consider is drilling one side of the leg only (i.e. not through drilling both sides), if you also avoided a deliberate pattern with the holes you could well achieve some kind of a result without compromising the robustness too much.

If you can accurately measure the outside diameter and wall thickness, I will knock up a model on my cad system at work to let you know the benefits of the drilling. Unfortunately it’s not a finite element analysis system which would also tell us how heavy the camera/lens combination could be before it breaks :).

Surely it's the head and the fittings which contribute most of the weight? The tubes themselves are quite light.

Leif,

How much weight is your head having to support. I have 3 sizes of Benbo / Unilock ball heads. Medium 450 gram Small 250 gram. Big one is kinda nailed to tripod so a bit difficult to get off to weigh. I can do so if required and post a comparitive pic.

Don

The tripod weighs 2.5Kg. The ball head including quick release weighs 500g. So the total is 3Kg which is a fair bit over long distances. And then there is the padded case. I don't think the central part of the tripod (the main joint) is that heavy, maybe 1 Kg. The fittings are nylon hence fairly light.

The lower leg tubes are about 32mm and I guess the wall is about 2mm. The upper leg tubes are lighter though unfortunately they cannot really be drilled because of the way the locks on the lower tube push against the upper tube.

Leif

Leif,

The following is based on a 500mm long, 32mm diameter tube with a 2.00mm wall thickness.

The basis for the calculation is a weight reduction, expressed as a percentage of the original mass of the tube, based on 10 holes drilled in varying diameters from 2.00mm up to 20.00 (inclusive).

Further calculations can be made by multiplying the number of holes accordingly.

2.00mm……….0.07%
4.00mm……….0.27%
6.00mm……….0.60%
8.00mm……….1.08%
10.00mm……….1.69%
12.00mm……….2.45%
14.00mm……….3.36%
16.00mm……….4.44%
18.00mm……….5.68%
20.00mm……….7.12%

Hope this helps.

Cheers,
Steve

Steve. Thanks. It does look like it is not really worth doing. Leif

I have visions of the tripod crumpling when you try to use it if you take to much off.:eek:

Christine. Yes, eek indeed!

In my experience it is not always obvious what works and what doesn't which is why I asked here. There seem to be some engineers on WPF judging by previous threads.

I know from previous experience of making a telescope mounting that a tube is much more rigid that a solid bar of the same mass per unit length. The reason why I think that is true is because the rigidity scales with the 4'th power of the diameter. (I'm remembering back many years but I think that is correct.) I suspect that for the same reason a perforated tube is more rigid than a smaller diameter non-perforated tube having the same wall thickness and mass per unit length. That is also consistent with the fact that things like tall cranes are made from a metal lattice rather than a solid bar.

I've also heard anout Sachtler tripods which claim high rigidity though I'm not sure why.

Leif

The gitzo carbon fibre explorer range is lighter and extemely versetile in a similar way to the uniloc - I just can't afford one! :(

Yes it is. The aluminium one weighs the same, and costs twice as much. The CF one weighs 400g less, and costs four times as much. Ouch. I was tempted, but I took a look at the design. The centre column has a simple pivot, with a small contact area. To my eyes it does not look all that rigid. In comparison the Uniloc centre column is an integral part of the central locking mechanism, and looks very sturdy. What's more, to loosen the centre column and the legs on the Uniloc requires turning one handle. On the Gitzo there are 4 controls to loosen. I would rather have the more sturdy and easier to use Uniloc.

I would be interested to see tests of the Gitzo and the Uniloc to see how they compare in terms of stability. The Gitzo would need to be more stable to justify the huge price IMO.

Leif

All true, I've never looked at the Gitzo explorer in the flesh as the price is far more than I can even attempt to justify, especially when you have to add the cost of a head. I have the original Benbo Trecker, which is very like the Uniloc, and have never really got to terms with the way it works regards the turn one handle and everything is loosened. All too often everything ends up as a heap on the floor and my blood pressure through the roof!
Manfrotto do some nice light carbon fibres at a more reasonable price but
not as versatile. Its a case of body building and the Uniloc or a less versatile carbon fibre. There are also methods of carrying the tripod as along the lines of Manfrottos bucket backpack or quick action strap where the weight again goes on the back.

Mike: Maybe I'm stating the obvious, but the trick with the Uniloc/Benbo is to grip the camera, or centre column near the camera before loosening the main bolt. I don't find it difficult since I realised that one important rule though I've heard many comments from people who do not like them. I find other tripods more fiddly.

I don't think they are so good for heavy lenses such as a 500mm F4 though I guess the trick there is to mount the camera and lens after setting up the tripod.

Leif

Leif: Thanks for the advice, I'll give it another go. I bought the Benbo for its positioning versatility for close - ups/macro shots.

Mike,

This just made me go out in the garden and check my technique. I seem to always unlock the central bolt with one leg on the ground, then spread them out as required and adjust position of the centre column. I have also realised I never have the camera on initially. For fine adjustments I have the camera on and move one leg at a time.

Comes quite naturally to me and I had to re-run several times and note what I did.

Don

Again, thanks Don. Come the weekend I'll delve in the back of the cupboard and find the demented son of bagpipes and have another go with the combined advice from you and Leif. It would be nice to master it as the thing obviously has great potential.