crossthread
Titanium
- Joined
- Aug 5, 2004
- Location
- Richmond,VA,USA
First of all let me state a few things which should eliminate a lot of conjecture. My lathe does not turn OD tapers. I have however had problems over the years boring tapers. I have tried different bars with more or less the same results. This is not heel drag, tool geometry, or any of the common mistakes that I can see. I almost always need to take a couple of spring cuts to creep on a dimension so I have to assume it is flex in the bar which is all too common. The bars I use (and I have quite a few) are always as large as possible and range from tool steel to solid carbide. I get these results even boring a 1.5" hole with a 1" bar. Now here is my question. If it is flex in the bar, why does it change the farther down the bore hole you go? That seems to me to be the only reason why you would get a tapered bore. The taper can be as much as .002" in a 5" bore of 4140, not that it should make any difference what I am boring and it doesn't. Anybody else experienced this? Thanks.