Alien: Mechanism in the arm

Source  http://www.thepropgallery.com/alien-bts-props

leading from

Alien: Creating the Alien

a) Taken in the work room of Brey studios, a photo of a mechanical version of the the lower arm of the alien on a work surface.

b) The arm is wired up and held in a diagonal position by a vice

c) In the background Guy Hudson wearing a brown red jacket is seen bending over smiling away.

1. At Practical Effects Group on Facebook, Till Bamberg posted a photo of this strange mechanical version of the alien hand with the caption "Testing a mechanical hand for ALIEN (1979)."(source Facebook June 12th 2019) Nicky Allder join in with the thread.
2. Nick Allder : A very young Guy Hudson (source Facebook see thread June 13th 2019)
3. Dominic Kulcsar : I'm wondering who built the mechanisms, etc. The special effects team, David Watling or perhaps Carlo De Marchis?
   Nick Allder : Dominic Kulcsar, I did (source Facebook, see thread August 6th 2019)

Source Sci-Fi & Fantasy FX #48