[morgandeo]

Hi,
I have to find out some information on steel that suitable for spindle.52100 is a high-carbon chromium alloy steel, which, because of its versatility, is used in a variety of mechanical applications. In the annealed condition this steel is comparatively easy to machine, yet very high hardness and abrasion resistance can be developed by heat treatment to make the steel particularly suitable for applications requiring extreme wear resistance. In addition, 52100 alloy steel can be heat treated to high levels of tensile strenght and fatigue strength.

[NC Cams]

52100 is "bearing steel". what you want/need in a bearing is NOT what you necessariily want/need in a spindle proper. Yes, 52100 can be relatively easy to machine but issues have been reproted by folks not well versed in machining of the steel.

Yess, you can get high hardness with 52100 but simple "high hardness" isn't all thay you want in a spindle. YOU may want a tougher steel, or a stable steel, or a less costly steel. A lot of these issues were discussed earlier in the thread.

4140 or 8620 might be much more economical than 52100 to use in one spindle as opposed to another. Simply using 52100 because it is available or becasue it is "wear resistant and has high hardness capability" may not be the best reason to use it for a spindle. IT all depends what you're looking to achieve.

Thre is no "fits all" steel for everything. IF there was, the specs would read, "it rusts, it sinks and it is magnetic". That is the only fits all steel I know of but that rules out all of your austenetci steels - such steels are typically NOT magnetic. .

[ckelloug]

Almost everybody who has commented has more steel selection experience than I do. The only thing I can add to the discussion is that S7 is somewhat difficult to machine on lightweight equipment. (I have a Birmingham 14x40 lathe I bought from a friend)

I've been making tap guide bushings lately from a piece of S7 my metal supplier handed me as a gift one day. It will work harden and tear up low quality HSS parting tools really easily. I've had decent luck turning it but it does wear out HSS. A better experience will be had machining it with carbide.

Heat treat on most big tool steel parts seems easier to farm out than to try to do at home unless you have a large accurately temperature controlled furnace.

--Cameron

[MustafaOzkarakoc]

We have used spindle material DIN 1.2379 for grinding machine. Thearded section cracked with brittle. Hardness of spindle is 50-54 HRc. Do you have any recommendation for material selection?
Regards.

[joeavaerage]

Hi,
my goto steel is 4340, its a low to medium carbon chrome-molybdenum through hardening steel. It is usually supplied as hardened and tempered to about 1000MPa and a hardness of about 48RC.
Its strong, tough, can be machined as supplied (with determination and a rigid lathe) and is readily available from just about all steel suppliers, and is far from outrageously priced.

If you want to harden the internal taper to forestall wear, that can be done with 4340, including carburising and nitriding, however there may be better choices if you want to post machine harden.

I tend to use 4340 as supplied, its great for axles, high tensile bolts/screws and has good impact toughness. It's not hard enough for cutting tools but I would have thought hard enough to prevent wear
even in the taper of a spindle.

Craig