O-1 self hardening

[jfsmith]

I am machining a piece of O-1 and it seems that it is getting harder the more I work it. This is the first time that this has happened when working with O-1, but I am doing a very complex pattern that is about .25 deep in to the surface.

Does this happen to any one else??

Jerry

[mochinist]

Its called work hardening. It happens when the metal gets heated up by your tool. You might try slowing down the rpms and using flood coolant if possible.

[CCWKen]

I'm thinking it may be the quality of today's stock too. I've been using a lot of W-1 lately and I'm always hitting hard and soft spots during a drill or bore. I suppose it could be work hardening but I use flood cooling aimed right at the bore or drill tip.

Some areas cut like butter then all of a sudden I'll get broken blue chips. A half inch deeper and it's back to long curls.

[wierdscience]

O-1 if you allow the tool to dwell will harden coolant or not.
I have noticed that the plain vanilla O-1 is less difficult to machine than the "decarb free" variety,dunno why.

[Spin Doctor]

With HSS end mills slow speeds and lots of coolant. And not the whimpy water based either. A good high quality cutting oil. Sure it's messy and one drop on your skin makes you feel like you went swimming in it. But it works and that is the point.

[mochinist]

This is true Weird I should have mentioned dont let the tool dwell also.

[toolmakerjim]

dont let O-1 get hot then use oil as a cutting lube. you'll find out why its called oil hardening...jim

[Elninio]

could be because the cutting tool is getting worn out also, but im not sure

[J Tiers]

I dunno, I got some O-1 from Victor or the like, and it was almost the easiest machining steel I had ever worked with. Package says it is AISI O-1, in the annealed state.

Made a punch and die set out of it, and had no trouble. Maybe you are going over it a lot as you develop the part? That could mean you are going back over material that was moved and hardened, but I never noticed such an effect.

The worst stuff I ever tried to use I don't know the type of. It looked like hot rolled.

it ended up as this vise, but it was really nasty. Work hardened in a second, if you didn't keep a deep cut going on it. Obviously not stainless, it rusted. The dark part is the mill scale, I left it on the top.

[BillH]

Im making the axles for my locomotive in 0-1, and I find the last .001 is sometimes hard to take off, I should just skim the last cut at .004.