Sherline 2259 80° Carbide Insert Holder with Insert

About the Insert Boring Tool Holders

These 3/8″ diameter boring bars hold a carbide insert secured with a Torx screw.  Each comes with either a 2-sided  55° or 80° carbide insert and Torx wrench. The 55° RH boring tool will fit into a 3/4″ starting hole. The 80° holder will fit into a smaller 1/2″ hole. The 80° holder offers a little more strength for roughing cuts while the 55° insert will cut into sharper corners. The 3-1/4″ long holder can bore a hole a little over 2″ deep with two fastening screws tightened on it. The holders are made from 1144 Stressproof steel with a black oxide finish. Available individually, or as a pair at substantial cost savings.

Advantages of Using Carbide Insert Tools

Though relatively expensive, if a cutting edge of a carbide insert becomes dull or chipped, the insert can be removed and rotated 180° to expose two new cutting surfaces, providing, in effect, two tools for the price of one.

The primary method of cutting metal on miniature machine tools is usually with high-speed steel tools as they are inexpensive, easily resharpened and can be ground into “form” tools for special jobs. However, inserted tip carbide tools can be lifesavers for some jobs. Though more expensive and not able to be resharpened, carbide tools hold their cutting edge when cutting exotic metals like stainless steel or titanium or abrasive materials like carbon fiber and can speed up the cutting process. This is why they are used for most cutting tasks in the modern professional machine shop.