This article shows making two projects - 

1. A boring bar holder, designed for use in the four-way tool post of my lathe.  Material is mild steel. 

 2. A boring bar for a carbide insert. The boring bar is 10 mm diameter, approximately 150 mm long, and made from free-cutting steel. 

Machining the end of boring bar holder.

Lock the holder in the toolpost and drill a center hole,
Reaming to 10 mm after drilling.  Ideally the boring bar should be a neat slide fit.

Slitting the holder with 1 mm saw.

Machining  cutout in boring bar to accept carbide insert.

See Article Number 23 for making a rotary table.

The boring bar and holder  performed well during initial test.


Close-up of the mounted insert and the cutout to accommodate it.