|Single Flute Countersinks. Industrial Quality Countersink. Wholesale 60 degree Countersinks. Combined Drill and Countersinks are made of High Speed Steel for sale by Bisco of Florida. Bisco also sells left hand countersinks and cobalt countersink. Order countersinks today! Keo cutters and Keo brand countersinks are available upon request. Bisco Tool Supply also carries drill bits,metric drill bits,carbide drill bits, end mills, abrasives, drill chucks, Jacobs drill chucks and more!