Invar 36 and SF/M

Did you request material spec's from the supplier? Specifically recommended cutting speeds, etc?

It cuts like low carbon steel.

That's pretty much the way I recall it behaved, but I wasn't sure. I've machined it only one time, and that was well over 20 years ago. The real surprise with the material is if you have to supply it. I was smart enough to request the material be supplied, a very small piece, a component of a tool I was building for the customer. Turns out the piece would have cost me $1,000 to buy because of a minimum order requirement. At that time the material was not readily available. Don't know about today.

Harold

I haven't machined it but I picked up a bunch of 1/8" TIG rods of the stuff surplus. It's 36% Ni with the remainder Fe. Its primary feature is very low thermal expansion around room temperature. It's not hard. Handles about like mild steel. Seems to have good deoxidizing properties and is good for clock penduluums.

Ted

The low thermal expansion and deoxidizing properties would likely explain the reason for its use in the tool I built for Litton. Thanks, Ted. I have always wondered just what properties it possessed and why it might be used when it's so expensive to purchase.

Harold

Interesting. I had considered that it might be a space-age alloy. Just goes to show not much is new!

Thanks, Randy.

Harold

Sounded like a good cast iron type - with the Nickel - never know. Martin