Shares of precision tool maker Renishaw's plummeted on Thursday after the firm admitted that revenue growth in the three months ended 30th September was lower than planned. By 12:11, shares had tumbled 16.97% to 853.5p after the group revealed that revenues rose by just 15% in the first quarter to £70.5m, compared with £61.3m the year before. Profit before tax for the first quarter fell from £15.1m to £13.6m.While Europe and the Americas achieved strong sales growth, revenues in the Far East - which the group said was an area of significant growth last year - were flat. Renishaw also admitted that it has seen a slowdown in one of its product lines sold to the electronics industries."Due to current uncertainties surrounding the global economy, the board is closely monitoring the group's costs and future recruitment strategy. Despite near-term challenges caused by the economic environment, we remain focused on positioning the group for further long-term growth," the statement said.Cash at the end of the period was £29.3m, slightly down compared to £34.6m at 30 June. The firm also revealed that it is reviewing its healthcare business and has refocused part of the activities to a smaller number of projects.NR