Going cheap with spring steel

[nnam]

What do you think of using spring steel instead of M2 tool steel for cutting bit?

Not going to work?

Not worth the efforts?

Have you tried it ?

The properties are very similar:

ASTM A232 Spring Steel vs. SAE-AISI M2 Steel :: MakeItFrom.com

www.makeitfrom.com

 

[jwmelvin]

I’m guessing it will lose hardness very quickly at high temperatures (not doing so is the point of HSS) and won’t work well for a cutting tool. For some specialized purpose where you need it only for a part of two - perhaps. But why?

 

[nnam]

I didn't think about the heat part. Thanks. On the why question, I was just wondering since they are very similar. But the heat part rules it out, which I didn't think about.

 

[ericc]

The referenced comparison chart is missing two crucial items related to Rockwell hardness. A232 tops out at 51, while M2 is 65. Hitting 50+ on spring steels is not reliable with home shop hardening procedures. And, due to the above red hardness limitation, you will need to run the spring steel tool at 1/2 the SFM speed. This may be very limiting. Another thing I never see mentioned is that if the tool ever gets dull or catches, it will experience local heating. This is absolutely fatal for spring steel, since it will go into a downward spiral quickly. You will have to cut the tip off and start over. This is especially annoying with a one piece boring bar, since if you cut off the tip, you might have to cut off the whole shank, and the tool will be too short. Beginners, especially, have a hard time hand grinding a boring or internal threading tool, and it is such a pity to have a decent tool and have a second's inattention causing the tool that took a day of tries to get working to be made useless.

Saying all that, I used a torch hardened piece of scrap spring steel to make an internal acme threading tool for cutting a new cross slide nut. It worked perfectly, and could readily be used for another nut should I ever need one. Of course, this was only used on brass. I have stacks of new HSS tools that I can use, but just wanted to try this out. I have had many failures and wasted days, though.

 

[RJSakowski]

Traditionally, springs were made from high carbon steel such as A1 and O1. Modern springs are made from lower carbon alloys formulated for "springiness" rather than hardness. As such, they may not achieve the Rc 60+ hardness required for a cutting tool. A good bet for a cutting tool would be the leaf spring from a 19th century buggy. The leaf or coil spring from a late 20th century auto may not be such a good choice.

 

[Todd3138]

I think you are getting solid advice from the folks here, nnam. In my blacksmithing, I actually use spring steel to make various tools such as punches, slitters, chisels, etc., but they have to be hardened and tempered before use. When using them on hot materials - similar to temps you'd probably reach while turning with a homemade tool like that on a lathe - I have to frequently dip them into the quench tank to keep the temper intact. Letting them get hot will kill the temper and they will just deform under the impact of a hammer leading to having to dress them again and go through the whole hardening and tempering process again. Definitely not what you are looking for out of a lathe tool!