MT 6 1/2 One Piece Dead Center

[erikmannie]

This is my first experience with cast iron. I know to clean the grit & cut it dry.

.010” DOC, 70 RPM, .005” feed, A6 carbide.

 

[erikmannie]

Here is the faced face plate. I faced .010” and then another .007”.

The cast iron makes such a filthy mess! I am going to remove this face plate & clean behind it before I use it.

 

[AlanB]

And such a lovely sound when cutting.

 

[erikmannie]

I am making the last one of these today. I am starting out with this 4” round bar of 4140 chromoly prehard.

 

[erikmannie]

The deepest facing cut I can make is .050”. I am at 380 RPM, .005”/rev feed, cutting dry, with a tired A6 insert.

 

[erikmannie]

I locked the carriage, introduced oil-based CF because I saw sparks, took a .010” pass & got this finish which encourages me to put on a fresh insert.

 

[erikmannie]

I think everybody would agree that this tip is in need of replacement:

 

[erikmannie]

I forgot to lock the carriage for this lubricated .015”pass (still at .005”/rev), but the fresh insert made the following improvement. If you look toward the center, it looks like I should choose higher RPMs. My machine jumps from 380 to 620, though, because I chose the easy setup of an RPC over the variable RPM that I could have had with a VFD.

 

[erikmannie]

I am facing the other side now .015”. I turned the RPM up to 620 and I got this:

 

[erikmannie]

900 RPM, lightly lubed .020” cut produced this finish, & this new insert tip is already showing wear.