FilaWinder Thickness Gauge Mount

Measure the filament as it spools with a thickness gauge. The gauge is available on Amazon and Ebay from a variety of sellers. Here is one of the cheapest -

http://www.amazon.com/gp/offer-listing/B008H1DL3M?ie=UTF8&condition=new&seller=AA3DL1YN5S7YK

The guide is sized for 1.75 filament.