The setting of the gauge is one of the most important settings on the comb. The gauge, or noil setting, determines the amount of fibre lost in the combing process, it also affects the cleanliness of the final product, the production rate of the machine and the Hauteur and CVH of the final top.

The smaller the gauge setting the less fibre will be lost in the combing process as noil. This results in lower production rates, for a given cleanliness aim, and more short fibres in the top. (i.e. Higher CVH and lower Hauteur results.)

A wide gauge setting has the opposite effect; cleaner top, higher production rates, lower CVHa and longer Hauteur. However, there can be a significant increase in noil percentage as a result. Normally gauge settings of 34-36 are required for fine long tops to enable the CVHa parameters of less than 45% to be achieved. Shorter gauge settings are possible (down to 28) for open top blends. As in all factors affecting the processing of wool, the exact requirements will depend upon the totality of processing factors starting with wool choice through scouring conditions, carding settings and gilling practices.

It is not possible to optimise a single factor but all of the settings need to be taken into consideration in order to calculate the most economical and effective settings for a given production process.