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Originally Posted by bobss396
In general, what you originally discuss is a "trepan" tool. These have a flat front and clearance on the sides. You can make them from almost anything. The parting tool on the right can be modified easily. They do tend to chatter, so keep the speed down and hold it as short as possible. You can face with them, taking shallow passes, they are a pain to get to cut on center. But if you can drill a pilot hole through, a counterbore is the way to go.
You can bore and face with the tool 2nd from right provided that the existing bore is big enough to accommodate the tool, and the material under the cutting edge is relieved so it doesn't rub on the bore you're trying to open up. For shallow work, these work good and can still be used for other work.
All of my tools are for Hardinge lathes with indexable turrets or Aloris tool post drop in tools. If there was anything special that I need, I make it myself. I've made smaller boring bars out of drill blanks, drill shanks that were cut off regular drills. These are high speed steel and can be modified on a bench grinder with a fine enough wheel (with a good sharp corner). The holders for these are totally homegrown. I made a set that is reamed for standard .125, .187, .250 boring bars.
Basically, I start with a piece of aluminum bar stock about 1.0" x .50" x 2" long, cut a ledge in it so it fits in my tool post holder. It gets held in to the tool post with the allen screws. I hold it in the tool post, put a center drill in a collet, do my center. Take that out, put in an undersized drill, drill that through, follow up with a reamer so the hole is true to size and the boring bar always cuts on center. This is kind of hard to visualize, but in reality the spindle is holding the tool and the tool post is holding the work piece. The boring tool is held into the new holder with either set screws or regular allen screws, usually a 4-40 or a 6-32 works well.
There are a lot of mini-lathe groups on Yahoo and other forums, you would be best off joining one of those. Micro Mark has a lot of goodies for the smaller lathes. If you're serious about it, make the one time investment in an indexable tool post, be able to grind your own tools.
Good luck, hope this helps, Bob
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