CHECH YOUR NUTS !!!!
Posted 26 June 2004 - 10:57 AM
Last year I attended a workshop in Sweden and during one of the days with the training of the hardmount, we (the instructors) discovered that the adjustible bolts in the socket block from my arm were bending. As I said, being in Sweden where they have supposedly the best steel, I had a famous grip-tech-maintenaince guy searching Stockholm for replacement bolts and he found them, rated at about 10.000 kgs pull force and about 1000kgs sideways.
Brand: made in Germany (not Sweden but still trust worthy in my opinion) by SKF, not a small company I think.
Today I had to shoot a commercial, 435 with Cook S4, nothing special. I build everything, check everything and it all works (converted Master,) I walk to the set, with the rig, no problem, put it there on the docking stand and wait till they are finished with the lighting. After 5 minutes, they are ready, I pick up the rig, swing in into DJ position (needed because of reflection and lighting) and at that time the top bold JUST SNAPS, the arm rotated on the other bold away from me and rips the rig out of my hand(=bruised by this movement), it hits the ground first with the base of Master, than flips over to crash the camera into the concrete floor.(Of course the carpet started about 30 cm further away.....)
Both bolds were screwed ALL THE WAY IN, no extention because I don´t need that with my DSD vest.
Still it just broke, about 10 months old, leaving me with a distroyed top stage, twisted sliding plate, bent gimbal arm-post and a 435 with a damaged eye piece, a damaged magazine latch and not on calibration anymore, so needed to be replaced.
Luckely I could do this day with a converted EFP and 3A arm (that needed repair too) that was brought in not long after the event.
The good thing was that all major powers (director, producer and client and DP) were very happy at the end and left the set with compliments and big smiles!
In the past weeks I have had BL4, Moviecam Compact, SRIII and 435´s, no problem.
This was a situation where there was no extra stress on any component, only swinging a well balanced and not too heavy rig from one side of my body to the other, in a relaxed movement.
SO, CHECK OUT YOUR BOLTS AND NUTS FOR ANY BENDING OR DAMAGE!!!!!!
So now into the insurance discussions..........
Rob van Gelder, Bangkok, Thailand
Posted 28 June 2004 - 02:16 PM
Sorry to hear about the big blowout. thanks for bringing it to the forum.
Did you find out anything more about those newer nuts you bought?
I am curious if you got some bad ones or if our backmounts are relying too much on these little nuts.
Has anyone else broken one of the threads before?
Posted 28 June 2004 - 04:09 PM
This is what I wondered too, are those bolds ( official name = rod-end bearing) under more stress than in BM than in the FM version.
It is possible, though I doubt that that is realy the problem. With the FM you have to extend one of them which makes it more vulnerable.
With BM they are all the way inside the socketblock and that could give more rigidety.
The precise physics are not known to me but as this accident happened under a very low stress level I think it could be a material flaw. The other bold was not damaged at all and still the total weight + speed and force was on it for a moment
Regarding availability....... that´s a different story, I´m trying to get a set here (imported) in Thailand but they are difficult to find, mostly out of stock and in back-order.
Rob van Gelder
Posted 02 July 2004 - 08:44 AM
The rod-end bearings are very hard to get en not sure about quality too.
That´s why I went to the metal-workshop with my drowing if a fixed adaptor because I don´t need the flexible solution with my BM vest.
Wonderful guys here in Thailand, their shop looks like shit, old machines and you wonder if this is going to be all right, They don´t speak english but are very interested so the next day I had my adaptor.
Back on the fly again!
Rob van Gelder, Bangkok, Thailand