Brazing Countersink Cutter -In order to ensure the firmness of the drill bit, we adopted a brazing method to weld carbide inserts. In this way, the drill bit can process harder metal (compared with HSS countersinks).But this will make the appearance of the drill bit not good-looking. We hope you don't mind. -Because the cutting edge of carbide material is very crisp, them machining environment needs to be stable to reduce beating. -It performs well when machining Non-ferrous metals, cast iron, General steel, alloy steel, etc. -Suitable for low rotating speed and low cutting allowance. High quality tungsten steel material is chosen for its sturdiness and high hardness. After heat treatment and quenching, thus making its drilling and chip removal stable, ensuring long-term use and high hardness material cutting, strong versatility and anti-shattering. Adopt brass brazing technology, which makes the whole alloy and the drill body fused together, welded firmly so as not to fall off easily and play an excellent fixing role. The edge enclosure is finely ground, which helps to improve the precision of drilling by making it smooth. Dimensions d16*12D*80L dmin=8~9mm d20*12D*80L dmin=9~10mm d25*12D*80L dmin=9~10mm d30*16D*90L dmin=11~12mm d40*16D*100L dmin=13~14mm Recommended RPM is about 200~300 Feed K: 0.15~0.25 N: 0.25~0.35 M: 0.08~0.12 P: 0.25~0.4 Works and reviews of clients (Thanks! HI, welcome to official store. -We are professional manufacturer ,development and production of milling tools. -We provide various tools for you . You can follow us and see more. -You have free choice of collocation, pick different specifications and other tools in our store to you cart and pay them together. We will send the products you have picked as a package. -Take an additional 5%~10% off when you buy 10 pieces or more. SHIPMENT -We have already paid 80% of delivery cost . -Orders processed timely after the payment verification.We ship products within 3 working days. -The trade is cross-border, and Airmail is cheapest post which take a long time for delivery.If you need the item urgently ,please choose Express way. -If you have not received your shipment within60 days from payment, please contact us. We will track the shipment and get a reply to you as soon as possible. We sincerely hope that tools will meet your full requirements. Please enjoy your online shopping.