rockcitycafe
I make things.
just designed and built a new boring bar for my bridgeport, the old one was just a 5/8 bar in a narex boring head, was easy to adjust but not all that rigid and boring a cylinder without chatter required 80 rpm and very small cuts. I did a few blocks this way but wanted to make something better, so I machined an r-8 collet onto the end of a 1.5" steel bar, then bored a crosshole to put a carbide holder I made in, the carbide holder puts the cutting edge at dead tangent of the bore, so things are more predictable and it's spring loaded, so adjustment is done with a micrometer and set screw, not as easy as the narex, but the thing is super rigid and lets me bore at the recommended cutting speed for that cutter and cast iron. rough stock removal is done at 325-600 rpms and .006" feed, it'll easily rough .010" in one pass and finish passes leave a very smooth bore, honing .001" removed all tooling marks. the finish bore is within .0002" taper and round, and after honing is just about perfect (see video), my honing skills are still a bit rough, so I put the cylinder .0002" out of round at the bottom...
http://www.youtube.com/watch?v=zuK5Hd0zyrU&list=HL1391864247&feature=mh_lolz
http://www.youtube.com/watch?v=zuK5Hd0zyrU&list=HL1391864247&feature=mh_lolz