what material is best for cutting steel?

Yeah, explain the problem.

Cutting with what, a saw, a mill, what?

A one shot garage project or a production line?

What kind of steel, mild, stainless, tool, etc.?

What kind of cutting?

Some hint as to the size of the working material.

funny

As a previous poster replied, this depends on the scale and scope of your enterprise, and what kinds of steel you intend to cut. If you can provide more contextual information, we can help you more.

That having been said, I like tungsten carbide for cutting steel in my workshop. Usually I am cutting mild steel, but sometimes need to grind off the heads of protruding drywall screws, which are made from ~600BHN (very hard, but brittle) toolsteel. A tungsten carbide high-speed cutter bit in my 5A (3/4 horsepower) drill is what I usually use.

A problem I have had with diamond cutting-tools in the past is that the adhesion between the diamond dust and the cutting wheel or saw teeth is poor, and my working surface sheds its diamond coating over time. I have not had this problem with the tungsten carbide (which is sintered into whole pieces). Possibly I've just been using low-quality diamond tools, so take this with a grain of salt.

Some disadvantages to the high-speed cutter bit in a handheld drill are that I cannot make precision cuts, and cutting is very slow. A friend has a CNC plasma cutter which cuts up to 1/8" thick steel very precisely and fairly quickly. If I had the spare cash (about a thousand bucks for the cheapest models), I'd get me one of those. I do not know how quickly plasma cutters wear out, or what they cost to maintain. I've window shopped some and drooled over several models, but even the high end plasma cutters seem limited to 1/4" or thinner steel plate, so one advantage to tungsten carbide cutters is that they can work through much larger thicknesses. If I had to cut through an inch thick steel bar, I would start with my WC cutter bit (which is 1" in diameter with a 3/8" shaft, so could cut to a depth of 5/16" around the circumfrence of the bar) and finish cutting the inner part (the remaining 3/8") with a reciprocating saw with WC-tipped teeth. I've never had opportunity to do exactly this, though, so I'm being a little speculative.

Another alternative is toolsteel, which is much less expensive than tungsten carbide or diamond. I don't particularly like using it, though. I have to take it slow and periodically drip oil on the working surface as I cut, or the toolsteel loses its temper and gets ruined (by the time you notice its color change, it's already too late). It also cannot be used to cut or grind drywall screws or other hardened steel. If you were setting up a factory for short runs of stamped mild steel parts from thin sheet, though, toolsteel stamps could be an economical choice.

I removed soc.zimbabwe from the followups (wtf?), and added rec.crafts.metalworking -- folks there would know best about this sort of thing.

Good luck,

-- TTK

---------------------- i guess you missed justone asoect of steel cutting:

ie what is healthier for the worker doing it

the Tungsten carabide is speading exaust gass and tiny waist dust in the air my guess is that it is very harmful for the lungs the diamind is apparently doing something similar anyway from my little practical work it seems to me that the diamond disk is less harmful for breathing (of the worker) am i right ??

TIA Y.Porat

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HSS (high speed steel) is cheap, and tools are easy to grind by hand once you learn how. Good for hand work on the lathe and mill, especially for the less hard steels. Not good for hard steels.

Tungsten carbide is brittle, but is harder than HSS and lasts a bit longer, and it can be used harder and hotter. Not so good for interrupted cuts. Brittleness depends on the grade of carbide to some extent. Better than HSS for hard steels.

Diamond is brittle, and tends to dissolve in steel, especially at high speed. Not really recommended for cutting steel, except perhaps at low speed.

CBN (cubic boron nitride) is about as hard as diamond, lasts well, but again is a bit brittle. It's expensive though, in practice about 2 or 3 times the cost of diamond tooling. Good for some production uses for hard steels.

The grade of steel and the cutting conditions affect the trade-off, as well as many other considerations like cost and time.

btw. I assume you mean cutting rather than grinding.

-- Peter Fairbrother