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Check your arm´s rod end bearings


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#1 RobVanGelder

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Posted 13 October 2004 - 02:51 AM

Hi everyone, I just tried some new rod-ends in my arm´s socket block and this is what happened after one day with a 435 and Cooke S4´s

Might be the japanese steele, but especially those of you with a BM harnass, should examine your arms closely...... <_<
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#2 RonBaldwin

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Posted 17 October 2004 - 09:50 AM

Agreed -- sometimes here on the forum I see pictures of arms with those screws backed nearly all the way out. They should always be in as far as possible and all the way in if using a back mounted harness (use the up/down socket block adjustment on the carbon arm instead). I think they are just aluminum?

Ron B
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#3 RonBaldwin

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Posted 17 October 2004 - 09:52 AM

Agreed -- sometimes here on the forum I see pictures of arms with those screws backed nearly all the way out. They should always be in as far as possible and all the way in if using a back mounted harness (use the up/down socket block adjustment on the carbon arm instead). I think they are just aluminum?

Ron B
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#4 PaulEdwards

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Posted 17 October 2004 - 12:20 PM

On a related point, I've just had to replace the spin balance male stud on an old Master docking bracket (the stud onto which you drop the gimbal handle for dynamic balancing).

Actually the stud was fine but it was the bolt which fixes it to the docking bracket which was bending over. I suspect that the fixing might had worked slightly loose at some point; putting greater bending stress on the bolt.

Anyway, worth checking for those with that type of bracket. Might just save a mighty embassasing crashing sound from the corner of the set!

Paul
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#5 joe mcnally

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Posted 17 October 2004 - 01:13 PM

Blimus
The two screws that hold the titanium dovetail to the back of the breast plate of Master series vests is another thing worthy of regular checks
Joe McNally
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#6 RobVanGelder

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Posted 17 October 2004 - 09:36 PM

Agreed -- sometimes here on the forum I see pictures of arms with those screws backed nearly all the way out.  They should always be in as far as possible and all the way in if using a back mounted harness (use the up/down socket block adjustment on the carbon arm instead).  I think they are just aluminum?

Ron B

<{POST_SNAPBACK}>



Even if you keep your rod-ends all the way inside the socketblock because of your BM harnass, you should check them: mine broke, all the way in and I did not use a front-mounted vest in a long time!!!
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#7 thomas-english

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Posted 18 October 2004 - 06:43 AM

On your rod-end bearing that sheared. Did it look like it had bent for a little and then sheared or had it just "fracture" sheared.

I.e. Is rod-end bearing shear preventable by checking for slight bend?
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#8 RobVanGelder

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Posted 18 October 2004 - 11:44 AM

It is hard to determine exactly what happened. The broken rod-end was also a little bend, as was the other one.
So it does seem that they first bend before they go.

And also here you can expect that the tougher the material is, the less it will flex and bend before it gives up.

For the backmounted harnasses be have to look with extra care, in my opinion: We are able with BM to hold the camera further out and also lift heavier camera´s with less or the same effort. Our body adapts and gives a sign when it is too much, but we should not forget that it also increases the stress on all the supporting metal parts!

And rod-end bearings are not made for our application, they are not so strong for side-way forces and that´s how we use them everyday.

My fixed block that I made in an emergeny after the crash works really well and secure, but only with BM of course.
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#9 Michael Stumpf

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Posted 19 October 2004 - 05:48 AM

Hi everyone, I just tried some new rod-ends in my arm´s socket block and this is what happened after one day with a 435 and Cooke S4´s

Might be the japanese steele, but especially those of you with a BM harnass, should examine your arms closely...... <_<

<{POST_SNAPBACK}>



Okay, slap me twice and call me sally, but what "rod ends" are you referring too and
what arm (BM harness arm or the arm, arm)?

I looked at that picture you posted, and I don't know, maybe it's because it's 3:50 in the morning and since I'm shooting nights I'm not thinking clearly, but those screws or whatever they are don't look familiar to me.
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#10 RobVanGelder

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Posted 19 October 2004 - 12:50 PM

Hi Michael,

The rod-end bearings (this is the official name) are the two bolts the socketblock from your arm, you adjust them in order to give the arm and post an angle to fly the rig neutral.
Sounds familiar now? :)

Rod end bearings are normally used in hydrolics and other machinery where levers, valves and such have to be moved.
This means that the forces are always or mainly in a straight line, in the direction of the mounted rod-end.
And this is just exactly how we DON´T use them in our arms.

My unfortunate accident has cost me about $ 3500, about $2800 has been covered by my insurance but the actual damage was around $7000 and I was very lucky, only a slight dent in a viewfinder and a broke magazine cover.

We put a lot of faith in some small metal parts......
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#11 Michael Stumpf

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Posted 19 October 2004 - 02:13 PM

Hi Michael,

The rod-end bearings (this is the official name) are the two bolts the socketblock from your arm, you adjust them in order to give the arm and post an angle to fly the rig neutral.
Sounds familiar now? :)

Rod end bearings are normally used in hydrolics and other machinery where levers, valves and such have to be moved.
This means that the forces are always or mainly in a straight line, in the direction of the mounted rod-end.
And this is just exactly how we DON´T use them in our arms.

My unfortunate accident has cost me about $ 3500, about $2800 has been covered by my insurance but the actual damage was around $7000 and I was very lucky, only a slight dent in a viewfinder and a broke magazine cover.

We put a lot of faith in some small metal parts......

<{POST_SNAPBACK}>



What arm do you use?
I use a PRO arm and the socket block doesn't have the screws to adjust the angle,
that part is in the "female" or "receiving" socket block on my DSD backmounted vest.
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#12 WillArnot

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Posted 19 October 2004 - 03:19 PM

What arm do you use?
I use a PRO arm and the socket block doesn't have the screws to adjust the angle,
that part is in the "female" or "receiving" socket block on my DSD backmounted vest.

<{POST_SNAPBACK}>

[/quote]


If one has a Back Mount vest then Yes, this adjustment takes place on the Carbon Arm of the vest, and the rod end bearings should be all the way in as described by Ron Baldwin.

All Pro arms have these rod bearings. Mine does. This is where the side to side adjustment (for your spinal comfort) takes place if you wear a front mount vest.

Look at your arm again. Hold the arm post farthest away from you and the male spud end of the arm (socket) facing you. You should see two holes, one above and one below the male spud. Recessed inside these holes there is a 1/4" hex bolt head. That is how you dial in or out the rod end bearings on the male socket part of the arm. It has been that way for 20 years at least. Sheesh.

Rob just did a little custom work so as not to have to dick around with the 1/4" hex bolt. What Rob is trying to do is what the new Master arms do in their quest for the 'No tools' design. My take on adding that kind of adjustability is that I only adjust that setting between Hi mode and Lo Mode (in a front mount vest), and Hard Mounts. The amount of time I make those adjustments to me doesn't warrant potentially weakening the design just to be able to do it with my finger tips. The Master arm works well, obviously Rob you need a little more consideration with your mod.
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#13 Michael Stumpf

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Posted 19 October 2004 - 06:48 PM

[quote name='WillArnot' date='Oct 19 2004, 12:19 PM']
[/quote]
All Pro arms have these rod bearings. Mine does. This is where the side to side adjustment (for your spinal comfort) takes place if you wear a front mount vest.

Look at your arm again. Hold the arm post farthest away from you and the male spud end of the arm (socket) facing you. You should see two holes, one above and one below the male spud. Recessed inside these holes there is a 1/4" hex bolt head. That is how you dial in or out the rod end bearings on the male socket part of the arm. It has been that way for 20 years at least. Sheesh.

Rob just did a little custom work so as not to have to dick around with the 1/4" hex bolt. What Rob is trying to do is what the new Master arms do in their quest for the 'No tools' design.

<{POST_SNAPBACK}>

[/quote]





I'll look at it closer. Coming from a Master's arm, and only owning my PRO arm for a little over a month, I haven't had a chance to fully look at every detail of the arm yet, because I went to work with it a couple days after I got my PRO arm. My rig is on the set and tonight, I'll take a closer look at the PRO's male socket block for these rod end bearings and make sure they are tightened all the way down.
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#14 RobVanGelder

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Posted 19 October 2004 - 09:44 PM

The Master arm works well, obviously Rob you need a little more consideration with your mod.

<{POST_SNAPBACK}>



Will, Thanks for explaining more detailed.
But I should have added some comments to the picture I´ve attached.

This picture shows the original socket block but with the adaption I made to get rid of these rod-ends.
It´s partly made with the original parts from the block, which was a no-tools design.
The bearings and knurled thumb-nuts are still there, but they have no use anymore other than holding everything firmly in place without open spaces.
That means that I cannot (comfortably) use this socketblock when wearing a front-mounted vest.

By the way, I use a Pro-gear / Sprint arm.

About Michael not knowing the place of these bolts: I did the same when I started with steadicam. But as I felt the operating was unpleasant, painful, I started to look how that could be improved. Only than I saw these 1/4" hex bolts inside the socketblock and found out about their purpose.

I started as an assistant to an operator who just hired an old MK3 rig and learned it himself. However, he could not do it for very long, his back troubled him and these little bolts were probably the reason as he didn´t know either and we didn´t have a manual. (it was in 1990 or so).

Now with people starting more and more directly into BM harnasses, these "little remains of the past" ( not completely true of course, there are still times you can use them) could be a source of trouble.
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#15 Michael Stumpf

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Posted 20 October 2004 - 11:12 AM

Rob,

I used a front mounted vest for my first three years of operating and still never
knew about the hex bolts on the socket block of my arms.
I went to the BM vest 2 years ago, and the PRO rig shortly thereafter, but kept my
Master's arm until early last month when I got a PRO arm.
I still didn't know about these hex bolts.
I've never needed to "adjust" them or have never had a problem with angle
on my socket blocks of either my Master's arm, Master vest, or my DSD vest or now my PRO arm..
But I'l be sure to check them from time to time as I do with the rest of my gear
to make sure they stay tightened.
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