Almost every family in the small Merseyside town has depended on the company for at least part of its prosperity for more than a century.
But the homely security of a job with "Pilks" has suffered a shuddering jolt during the past two years, as the company has struggled to slim down.
Pilkington has shed more than 500 jobs in its four St Helens plants over the last two years, and now employees fear that their futures are even less assured.
The company believes it can trim around pounds 100m from its pounds 940m annual overheads bill by implementing new cost-cutting measures over the next six months. Around pounds 60m of further savings are pencilled in by 2000.
One worker at St Helens said: "When [Italian chief executive Paolo] Scaroni is seen in the works he always has a mobile phone to his ear and never stops talking. He seems to want to do everything at 100 mph."
And the restructuring he has overseen, since his arrival from Pilkington's Italian subsidiary SIV in May, fits his image as an executive in a hurry.
Last week, the company announced it was to slash 6,000 jobs worldwide. It also revealed it was to focus its review on the downstream operation, proposing to close down or sell off around half of its processing and merchanting business.
There is also a rationalisation of its research and development operation underway, which has led to around 150 staff being cut from its Lathom facility near St Helens in the past month.
All this has led to heightened concern among the 3,000 employees left in St Helens, who have seen the company's plans alter course dramatically under Mr Scaroni.
Roger Henshaw, regional officer of the MSF, one of the biggest unions at Pilkington, insists that workers realise there is a need for change, but he believes that Mr Scaroni's accelerated timetable could backfire.
He said: "Pilkington has a history of excellent industrial relations, good conditions and a paternalistic attitude to its employees. But that could all be lost in the drive to ensure that it is a profitable, efficient market leader.
"Nobody is denying the need for change, but what has happened since Scaroni came in is that the process of change has accelerated."
Workers are also critical of the move to reduce the company's downstream operation, which they fear will strip the firm of guaranteed outlets for Pilkington glass.
And in a company that thrived on the success of pioneering the float- glass process, which revolutionised manufacture across the world in the 1950s by using molten tin to carry glass from the furnace instead of rollers, employees are also disgruntled that jobs have been shed in research and development.
Mr Henshaw said: "In research and development, the company is asking for projects to be prioritised, but this seems to be cutting costs in the short-term rather than taking a long-term view.
"It has to be difficult to prioritise in research because you do not know how things are going to turn out. Pilkington revolutionised manufacturing through the float-glass process and often development is about taking risks."
David Roycroft, head of corporate affairs for Pilkington, insists that the changes will reduce the company's overheads and consolidate its position as one of the world's biggest glass manufacturers.
He said: "When Paolo Scaroni came in, some changes had already been made but the feeling was that they were not taking place fast enough.
Pilkington believes that the reduction in its downstream operation will actually increase the number of outlets that buy its glass, because former local rivals, who would previously have avoided buying from the company, may now choose them as a supplier.
q Roger Bryson, chief reporter for the 'Liverpool Daily Post', has covered Pilkington for two years.