Steel

Tips and descriptions of materials you use

Steel

Postby Jerry » Tue Jul 20, 2010 12:03 am

Well, this is a broad one so I will just do a run down for now.

1018 - This is your generic low carbon steel. This stuff is crap to machine. Rarely leaves a good finish. If you dont want to pull out your hair dont buy it!

12L14 - Free machining leaded steel. Machines like butter, leaves a smooth finish, considered to be one of the most easily machines. Rusts easy. Will not make a structurally sound weld. During welding the lead vaporizes causing porosity.

1144 Stressproof - This stuff is great. Its internal stresses have been eliminated and machines very well.

4000 series - Chrome Moly steels. Available in a PH (Pre Hard) condition which is good for shafting. I have had very good results in turning and milling. When welding you need to watch out for your HAZ.

Drill rod - Also known as silver steel. This is hardenable rod available in air hardening, oil hardening, and water hardening. It is supposed to be use for tooling and is ground to size. Many people waste their money buying this because they think it is very round. Its not. It is usually triangular in shape and cannot be measured with a regular micrometer due to the grinding process. (Note: To measure roundness you need a V-Anvil micrometer) If you need round ground shafting ask for TGP or TG (Turned, ground, polished). It is heck of a lot cheaper than drill rod.

Hot roll vs cold roll: If you plan on machining it get hot roll. Cold roll steel is formed to shape while the steel is cold with rollers. This creates massive stresses in the material and will warp all over the place after you take off the outer stressed layer. If you take a cold rolled strip and face off one side it will turn into a banana.

This is a piece of 4142PH in my lathe for my conversion to brushless servo for the spindle:

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Re: Steel

Postby Doug Coulter » Wed Aug 04, 2010 11:24 am

One of my more useful hobbies is making knives, and I basically hate goopy stainless steel for that. I use A2 tool steel for cutlery, and S7 for cleavers that have to take a pounding.
I even built a jig to sharpen straight blades with a nice hollow grind on the lathe. And yes, Jerry, I can hear you wince from here -- know that I do clean the ways before starting and after every pass with this jig as they do collect grinding wheel bits. You remove all lube first, then use compressed air and wiping to get that off before it does harm.

Lathe jig

A2 is just within the limits of my heat treat oven, and is used in industry for slicing tools as it's about the best to handle abrasive things you'd cut. Which sometimes includes food, wood, and so on.
D2, also used for slicing dies in industry, is just a little past my heat treat speed so far. I'm thinking that an induction heater in vacum to try that one, and quench by letting helium into the tank.

This one benefits from multiple temper draws, with cold treat in between for the very best results.

S7 for cleavers is usually used here welded to a larger 1025 or so steel backing. I built a jig to hold my MIG head near the quill on the mill, and can make some really pretty welds using the table drives to get really even welding speed. Since the piece is there already, once it cools, you just come back with the end mill and "erase" the visible part of it after welding. Then do the heat treat.
When I use plain carbon steel backing for this I either electroplate it or blue it before use. You sort of have to when making a large knife or cleaver to keep the costs down.

I also use O-1 (cheap silver steel, drill rod, oil quench) to make some lathe tooling for slow cutting things. It won't take much heat at all, but when you need some odd form and don't care if the tool only lasts one job, it's pretty handy to have around. You just have to lube it well and go really slow to keep the heat at the tip down. This is an oil-quench steel, and I just heat treat it with a propane torch in small sizes I normally use. After quenching, I temper with the same torch. Some practice at it makes this practical, easy, and quick (and did I say cheap?). For example, I use tools made of this to cut perfect O ring grooves in vacuum sealing things -- but only in fairly soft workpieces like Al or brass.

I messed with W-1 (water quench) steel for knives, but that stuff warps on the quench sometimes even when you are careful, and tends to wind up on the brittle side unless you pay real attention to the quench so it doesn't harden all through.

Despite being nearly stainless in use, all of these are easily blued by the method shown here:

Mother of all bells made from a fire extinguiser

Yes, as Jerry said, steel is a VERY broad topic -- there are so many alloys specialized for something it will take a long time to cover them all. An old book from Carpenter Steel does a decent job, but hey, that's a whole book.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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