"The most unhealthy places to work were the flax preparing departments, especially in areas known as 'roughing' and 'hackling'. Here, work was carried out 'in a continual cloud of dust composed of large and small particles of fibre'....... in 1872, the average working life of an employee was only 16.8 years, and around 30% of the workforce could expect to die from .. lung diseases".

The above from the following site http://www.merriottfamiliesgenealogy.net/industry.htm

From this it would appear to be a term connected with weaving.