Getting A Decent Finish Cold Rolled Steel On Lathe

[Wreck™Wreck]

1018 CRS is not an ideal material if as-turned fine finishes are required, you will find that when making say 100 identical parts from the same 12' bar using the same machine, same tooling, same speeds feeds and DOC during the same day that you will get different results along the bars length. This I suspect is due to inconsistent manufacturing, remember that ANSI 1018 CR steel bars are about the least expensive cold finished material that one may purchase but is fine for its intended purpose.

You would see better results using 1215 or 1045 CR rounds, this will cost more of course.

 

[4GSR]

...snip....
You would see better results using 1215 or 1045 CR rounds, this will cost more of course.

Personally, I would go with 4130-4140/42-4145 instead of 1040/45. Cost a little more, but finishes much easier.
I deal with several screw machine shops and most will not touch 1018-1045 steel at all. Of course , they like 12L14, 1215, 1144 materials.
In my shop I started buying bits of 1215 and 1144 to make parts out of instead of 1018-1026-1040/45. I still have to keep 4140-4145HT on hand for certain things I build.

Ken

 

[cascao]

Shear tool isn't fast but is the best finish. See the test i've made: