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Arca-Swiss Z1 Stem Failure History

In early 2008 we were contacted by a customer who had recently purchased the Z1 Monoball from us, and he unfortunately had the ball head clamp twist on him unexpectedly in the field.  T hinking this was an isolated incident, we replaced the Z1 with another from our current stock and had him return the defective one to us for inspection. We were surprised when he reported a few days later that the replacement Z1 we sent him also had this failure occur at the stem upon use with the Sidekick.

Upon closer examination of the returned Z1, we were stunned to find that the stem was assembled in 2 parts that were apparently secured with a thin layer of adhesive. This adhesive came loose causing the two pieces of the stem to freely rotate, one inside the other. We also found that with enough force, the parts separated completely.

After further research, we learned that the USA Arca-Swiss repair facility, Precision Camera Works, experienced at least 2 verified cases of stem connection failure that occurred with normal use of the ball head (not used in conjunction with our Sidekick). A forum thread contained an example of this occurrence as far back as December of 2007:

We learned that Arca-Swiss changed to this 2-part stem design for the Z1 sometime in 2007.  We are not sure exactly when this change occurred in 2007.

We felt that the new design presented a substantial safety risk to our customer's equipment, especially when used in conjunction with our Sidekick (which creates greater twisting forces on this joint).  We immediately sent a warning note to our dealers, and any customers who had recently purchased a Sidekick directly from us.  We also recalled all potentially problematic Z1 heads that we had sold.

News of this problem quickly reached Arca-Swiss.

Issue Resolution

Arca-Swiss reacted swiftly to our concern about the Z1 Monoball two-part ball stem safety issue, and they have asked us to post a manufacturer’s statement.

  Arca-Swiss has informed us that they changed the assembly process for production runs of the Z1 Monoball after June 15th 2008, which they assure us will eliminate this issue altogether. Although the Z1 ball heads made after June 15th 2008 may continue to be the 2-part stem design, the stem is supposed to be threaded and fixed with adhesive rather than the original smooth, non-threaded, and potentially weaker stem.  

Our entire original stock of Z1 Monoballs with the two–part stem was retrofitted. In-house tests were preformed to gauge the strength of the reinforcement, and it was determined that the new threaded reinforcement is suitable for use with the Sidekick. We are confident that the threaded stem reinforcement design offered by Arca-Swiss is a more than suitable solution to this issue. We have been told that some Z1 stems were reinforced with a metal pin in the stem. We are optimistic that this pin is also a suitable reinforcement.

Arca-Swiss has agreed to reinforce earlier Z1 heads that have the non-threaded 2-part stem design; However this is strictly for 2-part stem Z1 ball heads manufactured prior to June 15 2008, and only if requested by a customer who feels it is unsafe to use in the field (please refer to Arca-Swiss’ statement for details). This is not a product recall.

If you think you may own one of the potentially problematic Z-1 heads, please complete our Z-1 Questionnaire. The questionnaire will help determine whether your ball head needs attention, and if so, what steps you need to take.

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