A few months ago I was needing to mill a 12” wide piece of steel. I noticed these cool fly cutter sets made by Suburban Tool but couldn’t justify purchasing the set. So, I made my own version....it uses a .750 diameter inserted boring bar. It works great!
-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
Inserted Boring Bar Fly Cutter
- Thread starter bac1972
- Start date
Max diameter is around 17”, but I haven’t tried it! The test piece in the picture is approximately 4”x7” but I’ve done 12”x12”
Thanks! You can’t clearly see in the picture, but the bar isn’t perpendicular to the spindle axis. It’s about 87.5 degrees and it is out of balance somewhat but not too bad. I slowed my machine down but thought about experimenting with a counterweight. I was mostly experimenting with the angle because of the geometry of the boring bar insert location itself. The insert leading edge came out close to 90 degrees this way. I also used a different bar (a TPG 322 insert style) other than the one pictured. It had a little more mass at the insert end. It was really all about trial and error and I got lucky !
- Joined
- Jun 7, 2013
- Messages
- 10,073
That could be an excessive load it impose on a lightly built milling machine, noting the R8 shank, the back gears are likely not designed for high loads and intermittent cuts such as those that the tool could impose, the spindle key is especially at risk of shearing off.
- Joined
- Jun 7, 2013
- Messages
- 10,073