Handwritten note by Magès on the replacement of the pump design and its machining defects (15/11/51)

A handwritten note by Paul Magès, dated 15 November 1951, announcing the replacement of a pump design and denouncing machining defects deemed unacceptable.

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Understanding this document

In this document

The note, dated 15 November 1951, announces that the pump then in use "is to be replaced by a new Magès design", with a drive "on the Fan Control shaft". The text specifies that the "drawing in progress at the BEA on 15/11/51 will replace this design" p. 5.

Machining defects noted

Magès describes the machining of the existing pump as "unacceptable" and details two specific points:

Element	Defect noted	Page
Cylinder of ø10, length 58	mounted with a clearance of 0.005	p. 5
Grooves in the pump body	uncertain mention ("precise" [uncertain])	p. 5

The sheet bears a signature at the bottom right, illegible on the transcription, as well as a graduated ruler printed in blue, probably related to the paper medium used and without any documentary value of its own.

Context

The BEA (Automotive Design Office) refers to the technical design department at Citroën where Paul Magès worked at that time. At the turn of the 1950s, the engineer was developing the principles of the hydropneumatic suspension that would later equip the Citroën DS (1955), and hydraulic pumps were one of the critical components of this system, requiring very fine machining precision — a clearance of a few hundredths of a millimetre being able to compromise the sealing and operation of the circuit.

Archivist's perspective

This short but precise note testifies to Magès' concern for rigour in the face of industrial manufacturing constraints. The explicit rejection of machining deemed "unacceptable" p. 5, for a clearance of only 0.005 on a small-diameter cylinder, illustrates the tolerance requirements specific to the hydraulic components he was developing.

It is likely part of the same work campaign as the pump drawing QM.399 D / E42.401 T and the annotated drawing E401.144c-147c, dated late October 1951, which already document handwritten observations on machining. The mention of the same day (15/11/1951) on the pump drawing with position mark suggests that this is a work file followed day by day, where this note would act as a summary or decision recording the abandonment of the criticised design.