Got lucky on this one

[larry_g]

As one of my first projects I was making a flycutter to fit in the R-8 spindle of my mill. Spent lots of hours turning, milling, drilling and tapping. I was quite proud of my new flycutter. Went to try it out and it would not pull in with the draw bar. Some investigating and I discovered that I had tapped the drawbar hole 1/2-20. Duh R-8 standard is 7/16-20. What to do, plug and weld, make a unique drawbar, and some other wild ideas. Thought that maybe I could Heli-coil it. Of all the good luck the tap size for a 7/16-20 Heli-coil is 1/2-20. I installed the Heli and all has been good for years.
dumb luck wins again.

lg

 

[joeby]

Hi LG,

All you need to do now is tell anyone who notices that the hardened insert was planned to prevent thread wear.

All good!

Good save BTW, most of my goofs have more involved repair techniques.

Kevin