Material Substitution

[Joe Pitz]

Hi All,

I have been looking through "The Home Machinist's Handbook" I would like to make some of the projects located in the back of the book.

Most of the projects call of 4130 steel. I would like to make the punch set and the machinist's jack set. They call of 4130 hex steel. I have looked at many online metal supply and the only material commonly available for hex bar stock is either 1018 or 12L14. I saw one article where someone used 12L14 to make the machinist jacks and then he hardened and tempered. But I was wondering what I could substitute for the punches.

I would like to make them out of stainless 303, but you cannot heat treat 303 stainless.

4140 is available but not in the smaller dimensions required, .250 and .750.

Any ideas would be appreciated.

Thanks

Joe

 

[RJSakowski]

Hi All,

I have been looking through "The Home Machinist's Handbook" I would like to make some of the projects located in the back of the book.

Most of the projects call of 4130 steel. I would like to make the punch set and the machinist's jack set. They call of 4130 hex steel. I have looked at many online metal supply and the only material commonly available for hex bar stock is either 1018 or 12L14. I saw one article where someone used 12L14 to make the machinist jacks and then he hardened and tempered. But I was wondering what I could substitute for the punches.

I would like to make them out of stainless 303, but you cannot heat treat 303 stainless.

4140 is available but not in the smaller dimensions required, .250 and .750.

Any ideas would be appreciated.

Thanks

Joe

IMO, neither 1018 0r 12L14 would be suitable for punches They may work for a jack but not the best choice of steel. 12L14 will not harden very well. It can be case hardened but that really won't suit your needs.

McMaster Carr sells 4140 hex stock but as a hardened material so machining may be more difficult. It is available in 3/4" hex but 5/16" is a small as it goes.

Is there a particular need for a hex shape? Part of the fun of machining is taking existing ideas and modifying them to suit your particular needs. Hex shapes are nice for mounting in a 3 jaw chuck but a square shape can be mounted in a four jar or you could turn on centers. Another possibility would be to use round stock and knurl to make a good gripping surface. There are many ways to skin the cat.

Good luck with your projects.

Bob

 

[Joe Pitz]

Thanks Bob,

I like the knurl idea, I want to learn how to knurl as well, might be a good project to start with.

Does drill rod come annealed? If so I can make the punches out of O1 drill rod and then heat treat and temper?

Thanks

Joe

 

[RJSakowski]

Joe,

What type of drill rod are you looking at? I believe the O1, and W1 (oil and water hardening) steel do come annealed. Not sure about the more exotic steels like A2 or S7A1 but you probably wouldn't be interested in those anyway.

M2 HSS comes in drill blanks which I have used for punches. I make a punch handle out of a low carbon steel and drill a socket for the HSS punch. The punch can be brazed in, silver soldered, or you can simply fix with super glue. The socket can also be reamed for a press fit and the punch pressed in. They are available in all the standard drill diameters so it's fairly easy to make up a nice set. They are hardened as received so any work on the business end would have to be by grinding or with carbide.

O1 is an excellent choice for punches. I would harden by heating to a bright red, followed by a quench in oil. Temper the punch by polishing to a bright finish and slowly heating from the struck end until the business end turns a deep straw color. That should be a good combination of hardness and toughness.

Bob

 

[Joe Pitz]

Yes Bob, I was thinking of either W1 or O1. I have heard that both are fairly easy to machine.

Interesting about the M2 HSS insert idea. I will try the O1 first to get experience working with tool steel and then try the M2 HSS.

I would image you would not have to harden the low carbon handle and since the insert is already hardened, you would just turn or grind to shape and then insert using one of the methods you mention.

Great ideas and some good projects to learn on.

Thanks

Joe