US No. 321 Mandrel – Busch Stainless Steel Mandrel, Made in Germany

The US No. 321 is the American number for a mandrel with a 5 mm head (ISO size 050): a stainless steel carrier that mounts abrasive and polishing discs in the handpiece. Busch & Co. manufactures it in Germany as Busch No. 305RS 050. Every US No. 321 on this page is a genuine Busch instrument and ships from our US warehouse.

Which US No. 321 Do You Need?

US No.	Busch No.	Material	Cut	Shank	Best for	Pack
321	305RS 050	Stainless Steel	—	HP	Straight handpiece: laboratory and denture work	6

HP (2.35 mm shank, straight handpiece). See the Busch Bur Size Chart for head and shank dimensions.

Clinical Uses of the US No. 321

Finishing and polishing: carrying abrasive discs for contouring and polishing composite, acrylic and metal.
Separation: carrying separating discs in the laboratory.

At 5 mm the No. 321 is a head sized for standard dental discs.

Speed and Technique

Fit only discs designed for the mandrel head, seat them fully, and run at the disc manufacturer’s speed; replace a mandrel whose head no longer holds a disc securely. Maximum recommended speeds for every Busch shape are in our Dental Bur Speed Chart, and reprocessing steps in the Bur Sterilization Guide.

Made in Germany by Busch & Co.

Busch & Co. has manufactured rotary instruments in Engelskirchen, Germany since 1905. Every instrument on this page is a genuine Busch product, precision-ground on a concentric shank under ISO-certified quality management and guaranteed to arrive free of manufacturing defects under our Busch arrival guarantee.