"all purpose" hardenable steel?

reading Jim K's informative thoughts on making a hardened index wheel, it occured to me that I've been aggravated lately by numerous projects that would best be made of a hardenable steel.

I use O-1, A-2, S-7, some W-1, and some HSS steels like CPM M4; and have a small controllable (programmable) furnace as well as a torch and bucket of oil. Trying to clarify that I am familiar with general small shop heat treat procedures for tool steels and making tools.

But I don't know beans about what is a good general (and hopefully cheap) hardenable steel to keep on hand for routine machine parts like tooling bushings, arbors, adaptors, index plates, spindles, collets, etc? For instance I'd like to make a bushing to convert the workhead on my Cincinnati #2 T & C grinder from #12 B & S to 5c; a press in flange for the opposite side (50 NT) to guide the new drawtube, and a new hardened drawtube for the 5c. Added up it comes to a somewhat expensive pile of steel if bought as decarb-free 3'rounds of tool steel.

I may or may not actually complete the described project, as 6H collets to fit the current set of adaptor bushings in the work head seem to be finding me. But it is representative of the type of project i'd like to have more info and options for material choice.

TIA,
smt

Well - a general purpose hardenable steel for machine parts.

First thing that comes to mind is O-1. It's a bit expensive, comes in bar stock and re-forge billets, and is availabile from specialty suppliers. It also forges and heat treats readily with simple equipment. Thanks to its machining properties its easy to hold very close tolerences and get refined finishes. It's also stable in heat treatment so long as the suggestions about part design and quench are followed.

To me 0-1 or its slightly more expensive brother 0-5 are superb all purpose steels.

If you don't need tool bushing hardenability I suggest 4140 and 4340 because they can be reliably heat treated to Rc 55. They're "non-free machining" alloys are tougher and more fatigue resistant than tool steel in most instances and much lower in cost. They distort a bit more in the oil quench. 4140 is also widely available in in a large selection of round, hex, and square bar stock sizes in several factory conditions (annealed, normalized, HT) and finishes, as rolled, turned and polished. 4340 less so but still available.

1040 can be used for heat treated steel parts. It's lower in cost and comes in the same variety of condition and sizes as 4140. Because you have to water quench it it distorts more in heat treating.

I'm letting my prejudice show. Mild steel, 4140, and O-1 are the only ferrous alloys I stock for general use. If you yeild to temptation and stock materials for contingencies that may never arise you'll soon be buried in materials and broke.

I have bits and pieces of other materials left over and over-orders but when they're gone (do the odd and ends EVER get used up?), they're gone.

for my shop, its all a-2 unless marked otherwise. I like the stability and thru hardening of a-2, you don't get oil all over quenching it, and it does not machine overly hard. I also use a lot of 4140 prehard. O-1 is a good alloy as well.

Carpenter Steel has a handbook called "Carpenter Matched Tool and Die Steels"

I have had mine for some time so I don't know if it is sill given away or chagred for.

Forrest Addy listed his peferrences by AISI numbers, this book crosses them over to Carpenter's trade names such as "Stentor, Hampden,Four Star" etc.

The book lists all the information a machinist might reasonably need along with heat treat instructions.

It also lists examples of applications of each alloy and the comparison of any one of the Matched alloys to its nearest brother alloys.

"Need it Harder go to----
need it Tougher go to-----
need more Wear Resitance go to----"

Carpenter sells dirtect, ships right away, and doesn't get snippy about small orders.

Makes life a lot easier : )

well drat, guess my rich and satisfying fantasy life has been shot all to heck! Was looking for "good" & "cheap" at the same time, and just assumed there had to be something out there to move up to once as guy's needs increased to the "few hundred pounds per year" level.

I do like 0-1 and A-2, for the reasons people have stated. Sounds like i better get a Carpenter's guide- thanks Jim.

Probably part of my pricing "dismay" is buying the wrong way. For instance, for many parts I don't need precision ground flat stock, but that is the only way to buy it in small lots (18" or 3' bars) and i suspect there is a premium attached. In decarb free rounds, it's not "too" bad from MSC, which has been my source (other than crucible) for the past 20 years. Without working too hard, can anyone comment if they are "reasonable" compared to ordering from a steel supply house?

Thanks all, for the input! smt