4140 annealed for parts...?

[EmilioG]

You probably use a 25 HP spindle machine. The BP is a medium duty mill. Maybe. With light cuts and good cutters.

 

[Bob Korves]

You probably use a 25 HP spindle machine. The BP is a medium duty mill. Maybe. With light cuts and good cutters.

Emilio, normalized 4140 and 4130 machine just fine if you just keep from work hardening them. In the unhardened state, you will not find much advantage in tensile strength or hardness or wear resistance over mild steel. Same with O-1 and W-1. To get the strength and wear resistance the carbon makes possible, you need to harden them. The added chrome makes them look nicer, and makes them more corrosion resistant, but that is about all. The molybdenum helps to keep the steel harder at elevated temperatures. Not much of that sounds like a fixture plate...

 

[woodchucker]

I've cut 4140 on my 9a. I used Hss.. Don't fret, it cuts easy.

 

[EmilioG]

It’s a finger plate. I already have the O1 cut and ready but I’m entertaining an alternative
I can get the 4140 cheap. And I do want the finished look and corrosion resistance of O1 or 4140. I can always harden later. I’ll give it a try.