Reply To: stripped cyl head bolt top right side on a 4hp 1973

[EUGENE NEKOWITSCH]

Thats a good video, the only thing he left out is make sure you remove the tang after you break it off. I agree with Frank, Heli-Coil inserts are the only way to go, thats all I ever used, never had a problem. When you buy a set get the various lengths the coils are used. I was taught back in the day, whatever size bolt thickness is used like 1/4-20 the heli coil being inserted must reach down at least 1/4 inch, I always went one size longer, in other words threads should’nt have to be any deeper than bolt thickness for maximum strength.
Another thing I noticed on video nothing was clamped down, he was holding vise with hand,
1) Make sure table you are using is level
2) Vise is great make sure piece part is level and square with drill press, use level or indicator, clamp vise and part to table so it doesn’t move, remember you got one time to get that heli-coil in the correct spot, takes a little more time but worth it in the end
3) I always used a lot of oil with this job
4) Make sure you have enough travel for drill chuck after tools are installed
5) They make a tool that fits on top of tap that also goes into chuck, so when you start to thread ,it will be going in straight
6) Have fun