What are these kind of assemble-able “Erector” sets generally known as or called

Yeah, newbies + metal drilling is usually a recipe for disaster.

Usually I'm a fan of having newbies use hand tools for a good while until they get the tactile feel of the tool and the material. That's hard to do in drills, though, as proper, usable hand drills are practically unobtanium these days. So I'd prefer newbs start with a drill press where parameters are easier to control. So let's talk about that.

To drill a metal, you start with what material it is, then you go off to a chart of feeds and speeds for what engineering and experience has shown is correct for that material. I work a lot with mild steel and I prefer to start with 1/8" drills because they're dirt cheap and they break about when they get dull.

So feeds and speeds chart tells me that for tool steel speed wise I should be at about 60 surface feet per minute, or 720 inches per minute. A 1/8" drill is about 0.4 inches circumference. So 720/0.4 gives me 1800 revolutions per minute.

Since we're not milling or lathing, and I don't have a drill press with an autofeeder, feeds must be dialed in "by feel". "Feed" coarsely maps to "pressure" when in a drill press or a hand drill.

When you have feeds and speeds correct,

• Cutting is efficient and makes good progress.
• Chips are long - they are not chips but slivers/tendrils, and they are so long and consistent that they threaten to wrap themselves around the drill bit! So you back off for a second which has the effect of breaking the tendril.
• The drill bit does not get hot.

So if the above isn't happening, newbies tend to go "oh, that's normal" and continue with bad technique. STOP. Don't have any tolerance for bad drilling into metal, because that only work-hardens the surface, making it even harder to get restarted.

First, make sure your drills are sharp.

Then, recheck your speeds and make sure they're at least in the ballpark. Like I said into hard steel you need 1800 RPM on a 1/8" drill. (more like 3000 RPM into mild steel). That can be a problem. Everybody these days has one of those studly drill-drivers which is mainly for driving drywall screws, and it maxes out at 400ish RPM. That would be about right for a 1/2" drill bit into tool steel, but the tool doesn't have the torque for that.

A Dremel moto-tool (whose arbor is 1/8") only develops significant power around 7000 RPM. Then there are the cheapie corded drill-NOT-drivers, which like to spin around 1500 RPM. They're not a bad fit actually.

For Feeds, you have to dial that in with pressure. And the usual mistake is to not use enough pressure and again, work-harden the material. IME enough pressure requires pushing hard enough. And - this takes skill - you have to push straight down the drill bit, not partly to the side, otherwise you'll break the bit! Note that the handle is not in line with the bit.

You know when you have pressure right, because you start getting lovely, stringey chips and cutting proceeds at good pace. Learn to do that again.

It is a slotted "L" bracket. It's available at most home stores.