Featuring precision machined shaft collar masters which accept 3-D printed inserts, SPARC Stafford Prototype and Repair Collar System lets users create working prototypes of special-purposed shaft collars within hours. Users can create custom-designed inserts with bores to fit virtually any type of shaft and can include holes, bosses, slots, tabs, hubs, and pulleys. Supplied in steel, stainless steel, or aluminum, masters come in 3 sizes to accommodate shafts from 1/8–3 in. O.D.