2-Boring on the Lathe - Boring bars

The oldest style of boring bar is the round shank with a hole through one end and a set screw in the tip to keep a high speed tool bit in place.

The most common boring bar in the shop would probably be the brazed carbide type. These are steel bars with a carbide tool bit brazed into the tip. They usually come in sets like the photo on the right. The sets come in various holder diameters to fit the tool holder being used. However the tools in each set are all the same holder diameter. The sets vary in length and shank diameter to suit the needs of the machinist.

Still another type of boring bar is the carbide insert style shown on the right.

If you chose to you could mount an adjustable milling machine boring head in the tail stock of the lathe and use the quill to feed into the part. In this case diameter is controlled by offsetting the adjustable boring head. The carriage is not used at all.

I have actually seen this setup run once. It was a long part that reached further than the carriage could be rolled out. The part was turning in a steady rest and the boring was accomplished as explained above R.S.