Challenge

Leeds City Council was constructing a new 'South' entrance for Leeds Central Station and requested a bespoke cast iron ground compass as a centrepiece.  The compass was to be embossed with selected international, national and local placenames, cities and points of interest, as well as key historical facts.  

The requirement was that the compass be supplied in SG (ductile) cast iron and left in a bare metal state to patina and weather over time.

ASF was approached with drawings already completed, to interpret and turn into the finished product.

Solution

As a bespoke product in cast iron, the first task was to produce a pattern for the compass.

The compass was planned in base sections totalling 17 parts, comprising a central rose pattern, 8 central surrounds, and 8 large outer spokes which housed the directional feature arms.  In addition to this, a pattern for each directional arm had to be produced, which took the pattern sections to over 70 in all and included 1786 individual letters - all produced and mounted by hand by ASF's own in-house pattern making specialists.

The manufacturing process then required sand moulds to be taken from the patterns. For this to happen the pattern was mounted in a box which was then rammed with sand mixed with furane resin (a setting agent) - this left an inverted inprint of the pattern that was ready to take the molted iron.

Each of the 17 base patterns - mounted with the directional feature arms, were cast individually on a 'one casting a day' basis, quality checked and the next section boxed and set for moulding.

The castings were then shot-blasted and dremelled by hand by the pattern-makers to ensure they were exactly as per the original drawings supplied.

Outcome

The ground compass is set into feature paving at the new south entrance of Leeds Station, where it is expected to last many lifetimes.