Drilling into steel-covered concrete
Ponderosa2
| Posted in Construction Techniques on
I am installing a vault door into a doorway. The doorway is a steel-frame cast into concrete. I need to drill ~10 ~1/2″ mounting bolt holes through the sheet steel and into the concrete.
Suggestions on tools or techniques? It there a bit that will get through the steel, not be destroyed by the concrete, so I can then hammer drill the holes to depth?
Thank you for your thoughts.
Replies
I'm a sucker for a great sales pitch at the trade shows. Two years ago at the JLC show I bought a set of Bad Dog drill bits. The guy doing the demo would drill into wood, steel, concrete, glass etc. He'd bend the bit while drilling to the point it would make you cringe thinking the bit would break, drill thru files, brake rotors etc. The bits are expensive but they are lifetime guaranteed, no questions asked. I would think one of their bits would do the trick for you. Here's the link http://www.baddogtools.com/cat.php?id=2
P.S. If I had a job like yours, I'd definitely give them a try, but I must say that since I bought the set, I really haven't used them so this recommendation is not from personal experience.
I almost bought a set of those, but they just seemed too good to be true.
Actual owner feedback is you still don't know?
Why don't you drill a hole through something weird and report back?
Joe H
O. K. I just did the "research". I used the Bad Dog 1/4" bit to drill thru a piece of steel 3/16" thick. The steel was sitting on a granite boulder. When I got thru the steel, I switched the drill into hammer-drill mode and kept on going into the granite.
It worked pretty well. It doesn't look like the bit is any duller than it started out. If I was actually doing alot of these I'd use the Bad Dog to get thru the steel then I'd switch to a rotary hammer for the concrete. Once you've used a rotary hammer you never want to go back to a hammer drill.
OK, not try drilling through a file.
Seems like there were lots of files with holes in them on their demo bench.
Maybe I need a set after all......
Joe H
If your frame will cover an ugly 1" hole in the steel, I'd oxy flame cut the steel first, then hammer drill.
Wear good leathers or old throwaway clothes, jeans and a sweatshirt only will have lots of little holes afterwards (dont ask how I know that<G>)
use a concrete bit, they will drill through anything
That seems like the simplest. I presume spinning the drill until it gets through the steel, then hammer drilling to depth.
How thick is the steel, we rotohammer through 16 ga. into concrete a lot with no problems. Use a center punch if you think is going to jump. Mike
Small wheel turn by the fire and rod, big wheel turn by the grace of god.
This is a great example of when you want to "shoot" your anchors in.
Otherwise, you need to adopt a two-step approach: a standard drill, sized to be larger than the screws, for piercing the metal, followed by the special masonry drill for the tapcon screws. Have plenty of standard drills handy, or bring the Drill Doctor with you.
Carbide hole saw?
I have done a number of similar frames and doors,not vault but heavy duty stuff.
I used to sharpen my drills with a stone mounted in an electric drill. I was very good at it then,got a drill doctor now.Anyway I found that sharpening a twist drill with a flatter angle than usual resulted in a hole that went extremely fast.You needed a drill bit with 118° to start with as the fast drill would skate until there was a dimple to hold it.Drill thru until it pops thru,withdraw the drill quickly and clean the hole with a hammerdrill and masonary bit or even faster a rotohammer.
The concrete will dull the bit, try to only drill thru the metal then switch to a masonry drill.If I was careful I only had to sharpen the bits 3 or 4 times a day.I am not aware of any drill bit that will cut both steel and masonry without quickly dulling the edge.
mike
I would use a rotabroach bit. You can get them through Fastenal.