concrete drilling

[fiddlewallop]

Hi All,

 

I am making a bench down my basement. I want it to be very stable, so it doesn't shift around when I'm carving plates. I was contemplating drilling a hole into the concrete floor and inserting some sort of bracket for the legs, to stabilize them.

Has anyone done something like this before? Good idea? Bad idea? If good idea, how'd you go about doing it?

 

Thanks,

FW

[David Burgess]

I have a couple of benches bolted to the floor.

You can get concrete expansion anchors at the harware store. When you screw in a bolt, the anchors expand to grab the sides of a drilled hole.

Using a carbide bit, drill the proper size hole in the floor. You may be able to do this with a regular drill and a lot of pressure. If not, most tool rental places have impact drills, and also have the carbide bits.

[Robert MacPherson]

Wallop,

 

My metal lathe is held to the floor that way.  You will be happier if you buy, borrow, or rent a "hammer drill".   A normal drill can be mind numbingly slow on concrete. 

 

Mac

[fiddlewallop]

OK, great. I think I might give this a try then. I was concerned that I might compromise the integrity of the foundation if I attempted this, but if you guys have done this, then I should be OK. I'll stop by the HW store and see what they have as far as expansion anchors. I think I have a hammer drill. Need to dig it up. Thanks! FW

[Jeff White]

OK, great. I think I might give this a try then. I was concerned that I might compromise the integrity of the foundation if I attempted this, but if you guys have done this, then I should be OK. I'll stop by the HW store and see what they have as far as expansion anchors. I think I have a hammer drill. Need to dig it up. Thanks! FW

Drilling, cutting should only be an issue (and not really one for what you are doing)if it is STAMPED (somewhere in big letters) that it is a "post tension slab".

[James M. Jones]

I have cast in in floor heating. If you do too, be careful not to hit a water supply line. THAT would ruin your day!

[Robert MacPherson]

I have cast in in floor heating. If you do too, be careful not to hit a water supply line. THAT would ruin your day!

James,

 

Now I have heated-cement-floor envy.  I wish the guy who built my shop building had thought to do that.

 

Mac

[violins88]

For drilling in concrete, you need a "hammer drill."  Mine has two modes -- regular drill and then the hammer mode in which the bit goes around, but also there is some kind of impact vibration going on.  Believe me, I have tried using a regular drill.

[David Burgess]

I think I used a regular 1/2" drill last time. Put a small piece of plywood over it and sat on it.   Went pretty quick. Not nearly as good as a hammer drill though.

[Michael Richwine]

Have a look at Tapcon concrete screws.  Still have to drill a hole, but it's a lot smaller and faster. They hold comparably to most expansion anchors and are a lot faster and simpler to install, plus they don't leave nearly as big a hole if you decide to move the bench.  Be sure and buy the drill bit that matches exactly.

 

They're my first choice fastening stuff to concrete.

[JTS]

There is also that epoxy made for securing anchor bolts to slabs where the contractor has overlook one or two in the original pour.That is great stuff.All the big box hardware stores carry it.You don't need to ask me how I know that

[donbar]

I have also had good luck with Tapcon concrete screws. 

Even with the feet firmly anchored there can be a lot of flex in the legs and their attachment to the top.i

The most rigidity would be added if you could anchor the top of your bench to a wall or pillar.

[fiddlewallop]

I will have to keep my eyes peeled for Tapcon screws when I swing by the HW store. I've never heard of the anchoring epoxy before either. Do you think this would hold up to the abuse it would take from constant vibration from carving a plate? Not sure if it would be brittle and crack when pressure was applied to it. Maybe not. Would probably prefer to not put holes in the concrete if that was an option.

[fiddlewallop]

I have also had good luck with Tapcon concrete screws. 

Even with the feet firmly anchored there can be a lot of flex in the legs and their attachment to the top.i

The most rigidity would be added if you could anchor the top of your bench to a wall or pillar.

 

Oh, that brings up a good point too. I think there's a concrete wall behind the bench that doesn't go to the outside. I could probably anchor the back of it to that wall, without worrying about cracking it on the outside and spurring a flood when it rains. That would be a good thing to do.

[FiddleDoug]

There is also that epoxy made for securing anchor bolts to slabs where the contractor has overlook one or two in the original pour.That is great stuff.All the big box hardware stores carry it.You don't need to ask me how I know that

  Just glue them in with some hide glue!

[~ Ben Conover]

Screw the bench to the floor and the wall where possible.

 

Screw some angled steel brackets to the bench legs, then mark out on the floor.
Use some plastic tape on your concret drill bit, for a depth stop.
Drill holes big enough for the rawl plugs, which fit the screws you will use.

Should take 10 mins.


 

[Robert MacPherson]

  Just glue them in with some hide glue!

Doug,

 

That's only if he wants to take the time to chalk-fit them.

 

Mac

[Michael_Molnar]

I anchored my benches to the wall. Now that is what I call solid!

 

[Don Noon]

My benches also are only bolted to the wall, and that is as solid as anyone would ever need.  I have a lathe, bandsaw, and small milling machine on them, and except for the bandsaw, there are no legs that go to the floor... just cantilevered off the wall.

[Brad Dorsey]

If you want a solid and immovable top, fastening the top to the wall will help more than fastening the legs to the floor.

[Bill Yacey]

Not all hammer drill are created equal. I've had quite a bit of experience with a couple of different types,  a Milwaukee that was fine for cinder block, brick and new cement, but when it came to old, hard cured cement, it would just burn up the carbide bits. A Hilti is the world leader in hammer drills, and will drill fully cured concrete like butter. If you can rent one of these, that's what I would recommend.

 

My experiences with Tapcons is they are fine for cinder block, brick and soft masonry, but they don't bite very well into hard cured concrete. I prefer the drop -in expanding anchors.

[Janito]

I have a nice oak floor, so my 300+ lb bench sits on a foam 'fatigue' mat sold by Woodcraft.  Doesn't budge a mm.

[Don Noon]

If you want a solid and immovable top, fastening the top to the wall will help more than fastening the legs to the floor.

Definitely.  That's why I did mine that way.

The bench runs the full length of the wall, bolted to every stud.  Diagonals go to the top of the foundation footing, screwed and glued, to support vertical loads.  I added one vertical support for the bandsaw, just to be safe (only press fit, and can be removed).

[jezzupe]

Oh what so everyones a contractor now too, geez man, back off!