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This is a directive to alert Carrillo customer and others who employ the 3/8 CARR fastener that the part has been re-designed. After thorough examination, testing, FEA's and the accumulation of results from both practical and failure analysis Carrillo and SPS Technologies have, in concert, redesigned the fastener.

The most significant differentiation to the customer will be the wrenching head size. Previous designs employed a 7/16 inch socket; it will now be 1/2 inch socket. The spotface pad will be larger, the registry under the head is shorter by .090 inch, the blended radii into the thread and registry has been reduced. These are the major alterations, but do not address several, more subtle changes.

The reasoning behind these alterations is to improve the serviceability of the part. Multiphase has proven to be a phenomenal material for this application; however it is our opinion that due to design, we were not fully implementing the advantages of the material.

We have attempted to emphasize the "stretch method" for installing our fasteners and we continue to do so. Installation requirements for the new fastener are identical to the older design. Although most customers do not have the gauging to measure, this new fastener alters the percentage of stretch to the critical areas of the fastener in an effort to enhance fatigue.

The redesign of this fastener began almost two years ago. Carrillo has been very successful with the present fastener design. However, with the increased emphasis on the reduction of weight we felt it imperative to address the fastener in an attempt to be pro-active to a means to avoid any potential catastrophes; we feel we have met that need.

If you have any further questions, please feel free to contact us.

As always, the above information is to be thought provoking and enlightening, hope we have succeeded. Thanks come back again soon!

Fred Carrillo and Jack Sparks
CARRILLO INDUSTRIES