Carbide Insert Radius Differences in Finish

[Amigo]

Wow Dave, there are a lot of ifs ands & buts involved to answer a question like that. Not having any more info than posted, I'll make a general statement that my help you but may not help the next guy.
Often a smaller nose radius, slower feed rate, RPM change & coolant will help give a nicer appearing finish. Sometimes, any one of those will help.

 

[Tony Wells]

Finish is as much a function or feedrate/nose radius as anything else. I believe there are some formulas for getting close to a certain RMS value on the finish. I don't remember them off my head though. There is a tradeoff in chatter control, however. Bigger radius = better finish, but greater possibility of chatter. But, for roughout work, larger radius inserts hold up better. Much depends on tool holder setup. Long reaches make a small radius perform better.

 

[HSS]

I'll have to agree with HSS (toolbits, not me) on CRS. I get a better finish when taking small doc getting close to finished size. I do ok roughing with carbide but when I get close I switch to HSS for smoother finish. My lathe prefers HSS and can be quite rough on carbide. I broke 3 inserts the other day turning down a hardened snap-on drift.

Pat

 

[rustybearing]

Is there a good place to order pre-sharpened HSS cutting tools? Preferably 3/8". My sharpening skills have not progressed enough yet to sharpen HSS.

 

[rustybearing]

Thanks, I appreciate it much.