Jump to content



Photo

ouch! My arm hurts.


  • Please log in to reply
14 replies to this topic

#1 Sandy Hays

Sandy Hays

    Member

  • Sustaining Members
  • 18 posts
  • New York City

Posted 08 April 2008 - 09:38 PM

Upon completing the third take of the day (a simple push in to a lock off) I was met with a resounding snap and disheartening shift in mass. The second AC and dolly grip thankfully took the sled form me. The camera (Arricam LT, zeiss lens, a couple of motors- nothing "heavy") did not crash to the ground, since the arm did not snap completely from the hinge.

A quick call to GPI secured a new hinge and socket block shipped out ASAP. Jack at GPI informed me that about 6 arms in the past year have suffered a similar failure. All arms were either in a back mounted vest or vehicle mount (I have used a Klassen vest for 3 years, the arm is about 10 years old).

I would love to know who else has experienced such a failure.

Sandy Hays

Attached Files

  • Attached File  arm3.jpg   56.82KB   374 downloads
  • Attached File  arm2.jpg   43.54KB   328 downloads
  • Attached File  arm1.jpg   38.72KB   294 downloads

  • 0

#2 Erwin Landau

Erwin Landau

    Advanced Member

  • Moderators
  • PipPipPip
  • 1699 posts
  • TBD

Posted 08 April 2008 - 09:51 PM

Hey Sandy,

Wow... I think to remember that Guido Lux had a similar incident....

Check out that thread:

http://www.steadicam...x...=3112&st=30


I had not as big of a failure:

http://www.steadicam...?showtopic=1695


Later,


Erwin
  • 0

#3 Alec Jarnagin SOC

Alec Jarnagin SOC

    Advanced Member

  • Moderators
  • PipPipPip
  • 1800 posts
  • New York City, USA

Posted 08 April 2008 - 10:01 PM

Sandy,

About as subtle as a cement block!!!! Wow - glad you and everything else is OK.

Something that should be noted is that several years back PRO switched to using a Steel socket block on the arm because of these breaks (again in vehicle mount & back mounted vests only). I believe Tiffen sells their rigs with a choice of materials for the same reasons????? What I find extraordinary about your break is that it is not where the Titanium is but rear of that which I assume is aluminum and very much the same as on the newer arms!!

Any thoughts people?
  • 0

#4 RobVanGelder

RobVanGelder

    Advanced Member

  • Sustaining Members
  • 919 posts
  • Bangkok, Thailand

Posted 08 April 2008 - 10:39 PM

I don't know how these parts are made, but it looks to me they are cast aluminium and then machined on the outside.
This part is hollow and so the full stress is on the outside of the structure.
Personally I would like to see a massive block here as this is the part that will have the highest stress of all blocks, together with the socketblock.
It is also under torsion stress, even more than the socket block in my opinion.
I don't think that a massive part here would give major weight issues for any operator.


(my socketblock and arm has now a massive connection, after that 435 and Cooke S4 crashed with my rig on concrete. not exactly the same kind of accident, but still....)
  • 0

#5 Lawrence Karman

Lawrence Karman

    Advanced Member

  • Sustaining Members
  • 896 posts

Posted 08 April 2008 - 11:54 PM

Holy crap! My titanium socket block split a few years back while on a vehicle mount and I've heard of others that had similar breaks, but I have never seen the arm break there. Going to take a close look at my arm tomorrow.
  • 0

#6 Jerry Holway

Jerry Holway

    Advanced Member

  • Sustaining Members
  • 737 posts
  • Philadelphia

Posted 09 April 2008 - 06:48 AM

FYI, the corresponding piece in Tiffen arms has been the same for years - at least since 1995, possibly back to 1978 (?), and is of a different construction.

A pix of the G-70 (with the "drop-down-kick-back" link) is attached for comparison.

Jerry

Attached Files


  • 0

#7 Alec Jarnagin SOC

Alec Jarnagin SOC

    Advanced Member

  • Moderators
  • PipPipPip
  • 1800 posts
  • New York City, USA

Posted 09 April 2008 - 11:15 AM

"the corresponding piece in Tiffen arms has been the same for years - at least since 1995, possibly back to 1978 (?), and is of a different construction."

Like I said, this is an usual break - everyone I've heard off has been in a titanium male socket block or in the rod ends (hell, I had rod ends fail in my 3a arm with steel socket block and front mounted vest). It is for this reason GPI (starting three or so years ago) started to offer you the choice of titanium or steel socket blocks (now they only offer steel). I was under the impression Tiffen also offered socket blocks made from both materials for similar reasons, but again, I've never heard of ANY arm breaking this far back. Weird.

I would still argue that both Tiffen and GPI arms are extremely well made, but that the arms were not originally designed to have the male socket blocks used at this angle. I had hoped that using Steel would end this issue - now let's hope Sandy's arm is a fluke!
  • 0

#8 Erwin Landau

Erwin Landau

    Advanced Member

  • Moderators
  • PipPipPip
  • 1699 posts
  • TBD

Posted 09 April 2008 - 03:35 PM

From the archives:


Guido Lux May 19 2006, 10:29 AM




Guys!

Backup seems the way to go no matter which arm you use!Since there's no titanium springs on the PRO arm...here's what happened to a friend of mine....!


Guido "stick with the backup theory" Lux



--------------------
Guido Lux

www.liquid-moves.tv

Attached Files


  • 0

#9 Lawrence Karman

Lawrence Karman

    Advanced Member

  • Sustaining Members
  • 896 posts

Posted 09 April 2008 - 05:52 PM

From the archives:


Guido Lux May 19 2006, 10:29 AM




Guys!

Backup seems the way to go no matter which arm you use!Since there's no titanium springs on the PRO arm...here's what happened to a friend of mine....!


Guido "stick with the backup theory" Lux



--------------------
Guido Lux

www.liquid-moves.tv



Well done, Erwin. If this has happened at least 2 times that we know of a redesign is in order. Be prepared to shell out more hard earned $.
  • 0

#10 Alec Jarnagin SOC

Alec Jarnagin SOC

    Advanced Member

  • Moderators
  • PipPipPip
  • 1800 posts
  • New York City, USA

Posted 09 April 2008 - 10:40 PM

Okay, I'm wrong about that one (or is it I "misremembered" where the arms broke).!!!

Doc, "If this has happened at least 2 times that we know of a redesign is in order. Be prepared to shell out more hard earned $."

I thought that IS why PRO redesigned the socket block! But, like I said, I think they only changed the titanium to steel. We should ask George if he changed anything else (Sandy's was an older version too).
  • 0

#11 Sandy Hays

Sandy Hays

    Member

  • Sustaining Members
  • 18 posts
  • New York City

Posted 10 April 2008 - 02:31 AM

Received new hinge with steel socket block today (previously had titanium). Hinge appears to be identical to the one that broke.

Sandy Hays
  • 0

#12 Jerry Holway

Jerry Holway

    Advanced Member

  • Sustaining Members
  • 737 posts
  • Philadelphia

Posted 10 April 2008 - 11:06 AM

A problem for all arms with the back mounted vests is the added stress on these parts, due to the constantly extended nature of the load.

Although the sled is typically in the same place relative to the body (so we don't feel anything new), the socket block is further away, and in a different orientation than the original design. It surely feels the stress.

So if there's any part that's weak or being constantly stressed in a new direction, well, failures are inevitable.

Both PRO and Tiffen changed the Titanium socket blocks to steel to accommodate the realities of the BMV's... now something else is feeling the new pressures.

No arm is immune from this; I'm going to push Tiffen to re-do the stress analysis on the complementary part in question on their arms...

Glad Sandy is back in business.

Jerry
  • 0

#13 Sandy Hays

Sandy Hays

    Member

  • Sustaining Members
  • 18 posts
  • New York City

Posted 24 April 2008 - 04:41 PM

Just an update. I received the invoice from Pro and the hinge was covered under warranty and my only cost was for the new steel socket block. More importantly, on closer inspection the new hinge APPEARS exactly the same BUT in fact the wall thickness is greater on the new hinge. The hinge has been re-made to deal with the added stress of back mounted vest.

Sandy Hays
  • 0

#14 Lawrence Karman

Lawrence Karman

    Advanced Member

  • Sustaining Members
  • 896 posts

Posted 12 June 2008 - 11:15 PM

From the archives:


Guido Lux May 19 2006, 10:29 AM




Guys!

Backup seems the way to go no matter which arm you use!Since there's no titanium springs on the PRO arm...here's what happened to a friend of mine....!


Guido "stick with the backup theory" Lux



--------------------
Guido Lux

www.liquid-moves.tv



Well done, Erwin. If this has happened at least 2 times that we know of a redesign is in order. Be prepared to shell out more hard earned $.



I would like to recant my previous post with apologies to the good folks at PRO. In a recent review of the PRO web site I noticed that the PRO arm chassis is warranted for life. That is why there would be no charge for replacement.
  • 0

#15 Brad Hruboska

Brad Hruboska

    Advanced Member

  • Sustaining Members
  • 157 posts
  • Toronto

Posted 13 June 2008 - 12:04 PM

For the unbelievers.
Yup heres my busted titanium socket block from a few years ago. Probably got its start at a crack on a vehicle mount. I notice the steel ones dont have that curve shaped lightening cut out anymore. I sometimes show this block to producers when they are pitching a heavy camera....
Brad.
Attached File  busted_titanium_socket_block.jpg   62.73KB   115 downloads
  • 0




GPI Pro Systems

IDX

Engineered Cinema Solutions

Media Blackout - Custom Cables and AKS

SkyDreams

Wireless Video Systems

Paralinx LLC

PLC Electronics Solutions

Ritter Battery

Betz Tools for Stabilizers

BOXX

rebotnix Technologies

PLC - Bartech

Omnishot Systems

Boland Communications

Teradek

Varizoom Follow Focus