stairs from rectangular steel tube?

You're talking about cutting a hole in one side of rectangular tubing at an angle to receive another piece of tubing of a smaller size as a tread or using "real" stair tread channel stock for the treads? I can't see how you'd have an issue with ragged cuts in 1/4" material with a good plasma cutter, especially since the end result will presumably be primed and painted which should easily cover any slight gaps. If you have that many cuts to make and given the simplicity of the cut, perhaps you could make a basic motor drive for the torch to maintain the proper cut speed for a clean cut.

Pete C.

PS: How's your liability insurance?

I'm talking about cutting the entire tubing into a sawtooth form, Pete.

Think of leaning the 3x10" tubing against the wall, 3" side against the wall - then cutting horizontal/vertical stair notches into it.

I could always use trim strips of thin flat bar, I suppose.

Grant

On Mon, 01 Oct 2007 14:04:52 -0700, with neither quill nor qualm, Grant Erwin quickly quoth:

Hmm, the "winding" makes it sound like a circular stairway, Grant.

How clean will they need to be? Won't the steps be welded in?

I'm guessing the 10" side is against the building at 45-60 deg and the steps will be cut into them at a compound angle. That ought to be fun to set up!

1) Plasma cutter and 1" sander to smooth it. 2) Bandsaw (crosscut) + Plasma Cutter (vert cut) + 1" sander to finish it off.

That sounds like an interesting project. I hope you post pics and the whole, sordid story later. ;)

-- Men never do evil so completely and cheerfully as when they do it from religious conviction. - Blaise Pascal

Ok, that description isn't making any sense to me. If I was making stair stringers out of 3x10 material, be it wood or metal, the 10" side would be against the wall (3" perpendicular to the wall), the length of 3x10 at the appropriate angle, and the stair treads can either be inset into the side (10" wide) of the piece, or notched into the "top" surface which is the 3" wide section. The notched in mode would be the least desirable to me structurally, vs. the side inset.

Either way, your plasma cutter should be giving you quite clean cuts in

1/4" material, if it isn't you need to determine why. Things like travel speed, air dryness, different consumable options, or even a different unit. Three stories of complex custom steel stairs should have enough profit for a good Hypertherm unit, perhaps a Powermax 1000 like I have which is plenty clean cutting 1/4" material.

Pete C.

It sounds like a carpenter wants some wood working done to steel.

The first thing that comes to mind is a Marvel bandsaw with about 20 ft of clear space all around. Barring that, how about a skil saw with steel cutting blade and jigs to guide the saw? The jigs would have to be good enough to flip the stringer and cut from both sides and have the kerfs line up.

Why bother to cut openings into the 3" x 10" stair stringer at all? All you need to do is make careful lay-outs of the tread location, butt it up, and place appropriate fillet welds. This is how it is done for commercial / industrial applications, except we use channels for the stringers... 10" or 12" wide depending on total rise.

A word of caution: Make sure the guard railing is in compliance with the building code; industrial requirements may be different from domestic / commercial where the public and children have access.

Wolfgang

would it be possible to use one of those "circular saw" type metal cutting circular saws? w/ steel cutting blade? still's gonna be difficult though. i only have limited experience with them, was cutting steel grating, the grating, after it was cut, pinched the blade and chipped off teeth, was a bummer.

b.w.

You should be able to do the cuts nicely with good layout and a piece of wood as a edge guide for the plasma torch. I would do all the cuts and not finish them until everything is cool even with plasma to limit distortion. You might scribe the lines and dress with a grinder if really necessary. Randy

I can imagine how that will look like, kind of. But how will the steps look like? And will the cutouts be closed? I mean if you are cutting out 1/3 of the rectangular, it will bend much easier. If you close weld the cutouts, the rectangular will end in a banana and you'll have a nice time flame bending it straight again. Interesting job, but a lot of work.

Nick

The cutouts won't be closed. I can't describe the topology of the stairwell because I've only briefly seen a plan, and I didn't fully understand it.

The weakness issue may become important, don't know.

Grant

Is there only one beam or two of them?

I've once built a stair out of 100 x 100 x 2 (mm ) as the single central beam. On top of that an angle iron for each step (horizontal; as wide as a step; one side of the L pointing upwards, the other horizontal). The steps were screwed on the angle and the other (frontside) longitudinal side sat on the step below with some soldid rectangular pointing down. The steps were out of grate (grate decking, grating). Prefabricated steps, cheap like dirt. It was a bit on the flexible side. :-)

Nick

Hi, Grant. So there are actually plans for this thing! Were they drawn up by a licensed engineer? If not, my advice is to run, not walk away as fast as you can. This sounds like a disaster waiting to happen.

The other problem is getting a building permit to install the stairs. Then there is the inspections, etc. If this is done without a licensed engineer signing off on the plans and without a building permit and without inspections, you will be on the hook forever. Your first mistake is to write about the project on this newsgroup. Seriously, a lawyer will Goggle this sometime in the future and will see your name.

Just my advice and not worth much, I am sure.

Paul

I knew a structural engineer who had the specialty of stairs, and that's what he and his other engineers designed all day, stairs and stairwells.

I was under the impression that stairs are easy stuff, until he explained all the regulations and showed some of the drawings and projects. It's interesting how the design of building is broken apart and contracted out to various places.