What Metal To Use?

[boostin53]

Okay guys, I have something to ask. I'm getting ready to order some steel to make another set of bullet swage dies. These dies are to make jacketed bullets. I'm not going to explain them in detail, plenty of reading available at the castboolits site if you wanna read.

I'm not really too worried about the steel grade for the core swage and core seat dies. But I am wanting a strong good steel for the point forming die.

For my last set I made, I used O1 for all the dies. I also made my reamer from O1, turned the bullet profile, milled the flutes, then heat treated/tempered and finally stoned the edge razor sharp. I'm looking to continue using O1 to make a new reamer, but wanting a different grade of steel to use for the dies. Possibly 4140 prehard. What does the hive say? Should I stay with O1 for the dies or is something else easier/better to use?

 

[Wreck™Wreck]

For how many parts do you require the dies to last?

 

[rgray]

My thinking is that 4130 is a step down from O-1 for a tool.....I could be completely wrong.
Always heard that D-2 was the best for toughness for a tool that's worked hard.

 

[boostin53]

For how many parts do you require the dies to last?

As long as possible haha. But realistically, I want them to make at least 5k bullets. The dies I made from O1 are going on about 8k bullets and still going strong with no problems.

I also didnt do a great job at heat treating them, but it worked and i have no clue on their hardness. I used a torch to heat them to bright red until a magnet was no longer attracted to them, then immediately dunked and swirled them in oil to cool. Tempered at 400 degrees for a hour.

 

[boostin53]

My thinking is that 4130 is a step down from O-1 for a tool.....I could be completely wrong.
Always heard that D-2 was the best for toughness for a tool that's worked hard.

That's what I was also thinking, but I have read many times of people using 4140 prehard and, according to them, have had no problems. This is why I ask here, where people work with metals almost every day. To get a better answer.

In this case, I may just use O1 again. Does anybody see anything wrong with using a heat treated O1 reamer to cut a profile in O1 before heat treating?

 

[boostin53]

Also, on the last set, I used O1 for the top and bottom punches. I need the punches to be softer than the dies. And since the dies were heat treated and harder than regular O1, I figured it was okay. Is 4140 softer than O1 in an unheattreated state and still retain good strength?

 

[blaser.306]

I use 0-6 for point form dies, o-1 for core bleed and core seat dies , and 1144 for my punches as it's shining feature is compressive strength. The 0-1 when hardened as you know polishes up beautifully with diamond lapping paste as does the 0-6, I polish mine to 14 000 mesh and have 0 issues with slugs hanging up. The best part of the 0-6 is the fact it is a powdered metal with high graphite content, when cutting a blind hole cavity the swarf comes out just like cast iron dust! It is just about as easy to harden with a torch as 0-1 as well.

 

[boostin53]

I use 0-6 for point form dies, o-1 for core bleed and core seat dies , and 1144 for my punches as it's shining feature is compressive strength. The 0-1 when hardened as you know polishes up beautifully with diamond lapping paste as does the 0-6, I polish mine to 14 000 mesh and have 0 issues with slugs hanging up. The best part of the 0-6 is the fact it is a powdered metal with high graphite content, when cutting a blind hole cavity the swarf comes out just like cast iron dust! It is just about as easy to harden with a torch as 0-1 as well.

Thank you for the recommendation!