Precious Metal?
January 23rd, 2009Not on North River Drive
I had a wonderful adventure today. I wandered up by the Miami River and got me some metal for a bandsaw base. On a reader’s recommendation, I went to a place on 20th street. Man, do they have a lot of metal up there. Seems like every business in the neighborhood sells metal and/or buys scrap. There are giant piles of rusty ferrous stuff and aluminum all over the place. It’s not far from the general area where one would look for machine tools, so I may go back next week.
I got myself some angle iron. Shouldn’t they call it “angle steel”? Anyway, I got some. I got 64″ plus 40″ of 2″ by 1/8″, and I got 13″ of 2″ by 3/16″. I think. Total cost? Under $26.00. Home Depot cost? I don’t know. But let’s put it this way: MORE. If they had what I wanted. And they would not.
I’m planning to miter-cut this stuff and make a box about 32″ by 19″, and then I’m going to use the heavier piece to make four tabs which will serve as attachment for casters. I’m a little nervous, because I’m wondering if I have this right. If I miter the cuts, I’ll be doing a butt weld on each corner. I hope that will be strong enough. Maybe I could weld a piece of scrap across each butt weld on the bottom.
I’m also wondering if 1/8″ will be rigid enough. I figured it would be, because the steel on my mobile saw base is very thin, and it’s not even angled, and it works.
We’ll find out, I guess.
It didn’t occur to me until I had bought the metal that mitering might be a problem. I can put it in the dry-cut saw at an angle, no problem. But to get a 45-degree miter, I have to set it on its base, with one wall sticking up perpendicular to the saw blade. This is a no-no for dry-cut saws. You’re supposed to lay the angle iron down so the V-shape is upside-down. This makes it more stable as the saw cuts.
I suppose a jig is the answer. HA. More fun for me.
I almost don’t care if it works. If the metal is too flimsy or whatever, it will give me an excuse to get welding practice, and I didn’t pay much for the material.
More
Working with tools is full of surprises.
I was trying to figure out how to cut a 45-degree miter in angle iron, without situating the iron improperly in my dry cut saw. It turns out there is no reason to try. The correct way to weld a 90-degree turn in angle iron is to cope it.
I don’t have a picture, but it’s easy to describe. Hold two pieces of angle iron at 90 degrees, in the position they would be in if you made a joint. You can’t do it, because the bottom parts collide, and even if they didn’t, the end of the vertical part on one would butt up against the side of the vertical part of the other. So you remove the parts that get in the way; take out the redundant metal. Remove a square piece from the horizontal part of one piece, equal in width to the total width of the angle iron. Then trim the vertical part of the piece you took the square out of, so it will fit inside the angle of the other pieces. You only cut one of the pieces of angle iron. Weld and pray.
Oh, forget it. Here’s a Youtube:
January 24th, 2009 at 1:07 AM
Re “angle iron”: steel is pretty much all iron anyway, but it does seem wrong to call it iron. Metalworkers who haven’t lived all their lives on a farm just call it “angle”. The “steel” goes without saying, same as for pipe, square tubing, I-beam, plate, etc. Also, if you say “galvanized”, you may omit “steel” and be understood, even though “galvanized” isn’t really a noun.
January 24th, 2009 at 3:48 AM
You’re on the right track about not bothering to miter the ends of steel angle to make your corners. In industrial work many times we don’t even bother to “cope” the ends. Just place two pieces parallel with the leg turned inside forming two opposite sides, then orient the two other perpendicular sides with the angle leg turned out and weld the “back” of those angles to the two legs of the other two angles. (it’s hard to describe in writing when a sketch would make it clear.)
The angle is pretty strong no matter how it is oriented. In the AISC steel manual we worry about something called “section modulus” and “neutral axis” when designing the member, but the bottom line is the angle has close to equal strength in any orientation as long as one leg is in the vertical plane.
For the money try to get thicker material like 3/16″ or 1/4″ because it’s easier to weld and not “blow through” with your rod or mig wire and it will not deflect as much. Of course if you’re building a watch or something that has to be light weight for a boat or airplane the thinner sections can be used.
Box tubing is also an interesting alternative because you get a flat surface on all four sides and the strength is uniform regardless of the orientation.
January 24th, 2009 at 8:41 AM
Actually, with say 1/4″ angle iron (steel), it’s not uncommon to miter, and then grind a chamfer onto the cut edges. You then weld in the resulting v groove and grind flush. Should work for 1/8″. With a cradle such as you’re making, you can then weld a plate underneath the joint that will also support your casters. Cut the 45s with the poor man’s band saw, the Sawzall. You could also cut the flat side up and flip it to do the other flat side up.
With saw blades, there’s a rule of thumb (your thumb may vary) that you want 4 to 6 teeth in the metal while you cut. So a one inch thick piece to cut would require a 6 TPI band saw blade. If you fed very slow, reducing chip load on the blade (assuming you have an 80 tooth blade) you could probably cut it flat side down. If you are not distorting the metal, you’re good.
http://www.offroadfabnet.com/forums/showthread.php?t=1192
January 24th, 2009 at 8:47 AM
I want to put the casters out to the side, for stability.
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I may have gone too thin with the angle iron. That was a natural reaction to my usual practice of overbuilding. If it’s too flimsy for a saw base, I can always use it to support a perch for the birds.
January 24th, 2009 at 8:49 AM
What’s fun is to hear someone call aluminum extruded angle, aluminum angle iron.
January 24th, 2009 at 10:21 AM
I’m patiently waiting for you to make something besides apparatus for your tools with your tools…
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Really though,I enjoy the metal stuff. I’ve been a carpenter for almost 25 years, but am a hack when it comes to anything metal. For the longest time, I had a foreman who was a whiz with metalwork. He worked for 10 years as a welder before becoming a carpenter. I regret I didn’t take any time to learn from him before he left my company. My welds still look like a pile of half-melted BBs…
January 26th, 2009 at 10:30 AM
All steel is iron, but not all iron is steel.