Bolting to concrete - removably

[Adrian]

I've got something that needs to be bolted down to the garage floor, but which needs enough working space around it that it's going to be a PITA if bolted down permanently. So I'm thinking in terms of putting fixings into the floor which I'll bolt it to as needed.

Looking at concrete fixings, the question that comes to mind is what'll happen when they're not in use. Will they come loose? Will they fill with dirt and crap? It makes sense to put the bolts back in the fixings to help stop that, but are they designed for repeated use, or are they effectively one-shot?

Thoughts gratefully received. The fixings won't be receiving heavy-heavy loads, mainly preventing rotational torque. (It's a manual car tyre- fitting machine)

[The Medway Handyman]

Drop in anchors should do the job

[Nightjar]

Rawlbolts can be bolted and unbolted at will and, if you screw the bolt in part way and hit the head with a hammer, they can even be removed when you no longer want them. As for filling with dirt, that will depend upon how clean the environment is.

[Adrian]

On Sat, 24 Jan 2015 11:00:31 +0000, Nightjar Rawlbolts can be bolted and unbolted at will and, if you screw the bolt

Thanks, Colin, and to TMH.

[fred]

In article , Adrian writes

A final alternative is a resin socket (the opposite of a resin stud):

IMV less likely to lose grip with repeated tightening and loosening cycles.

Like any floor mounted socket they will fill up with crap so fill with a plastic plug or grub screw when not in use.

[GB]

That's a hell of a trip hazard? Our garage door does not stop dirt and leaves getting in, so the holes would fill with crud pretty quickly.

Ideally, you want something that can be screwed in level with the garage floor when not in use. I was wondering about making U-shaped slots in the feet of your tyre device. Then raise the bolt heads, slide the feet under the bolt heads, and tighten down.

Rawlbolts would do, but a socket 'glued' in place would be better.

[Tim Watts]

I would cut the head off a stainless bolt or stud and cut a slot in so it could be glued in flush.

Resin/chemical sockets are the name:

[Brian Gaff]

Well, concrete is strong under compression, but weak in almost all other ways, so whatever you put in would need to have a large area in contact with the concrete to be reliable in the first place.

IE I'd dig a hole and put something down with all the fixing points joined together inside a bloody big chunk of concrete!

Brian

[Tim Watts]

I'll respectfully disagree.

I've seen some very big industrial robots bolted into an ordinary workshop concrete floor after the fact.

Concrete is weak in tension and also in bending (for the same reason) if unreinforced.

However, trying to pull a lump out of the middle of a slab will be extremely hard, unless the bolts are ridiculously shallow in which case it might pull a cone shaped lump out the surface.

Depending on what's being bolted down and how thick the slab is, I would be happy with 3+ inch resin sockets set in. 2" if it's something not exerting any turning/pulling forces.

If this is a car lift, then seek better advice! But it sounds unlikely as you don;t tend to remove those.

For the resin, use cheap Screwfix NoNonsense resin - this is actually pretty good stuff if you don't need some particular performance aspect of one of the fancy Fischer products.

Blow the hole out after drilling *hard* with a pipe that goes right in - you need to get all the dust out. A hoover will not be good enough.

Personally I degrease the fixings too - hot water and a bit of washing liquid or some alcohol.

[Adrian]

Mebbe a tad overkill!

[Adrian]

Four bolt heads sitting just proud of the floor?

Yeh, that's what I'm thinking.

The device in question is one of these :-

B000ROBCT2

The four legs each have bolt holes. People have reported having success just bolting them to a wooden pallet - without being bolted to anything, you just don't get enough force on the lever.

[Lobster]

On 24 Jan 2015, fred grunted:

Blimey, never heard of those. I can think of several times in the past where it would have been really good to haved use those in place of resin studs!

[Tim Watts]

Me too -

I have a use or two coming up that would suit these :)

[Dave Plowman (News)]

Assuming the concrete is reasonably thick, I'd just use Rawlbolts. You use either studs and nuts into them, or bolts. If bolts, you could just replace them when the device is removed. That would stop the threads getting full of crap. You might need different length bolts if whatever you're fixing is thick, though.

You can also remove Rawlbolts complete by tapping the bolt inwards while slack - that will push the wedge back allowing the whole lot to be removed. And they're cheap. ;-)

[Dave Plowman (News)]

They needn't even be proud - if you use a spacer (some washers?) between the bolt and housing when first fitting. Remove the spacer and the bolt head could be flush with the concrete.

[Adrian]

Good idea.

[Adrian]

7"+, depending on which bit of the garage. There's a two-post lift going in there, and the floor's intended to take that.

[fred]

In article , Lobster writes

I don't think they've really reached the mainstream yet but the prices have definitely come down, particularly those on Tim's link.

With the length of the M8s being in the 75-80mm range I can see them as being useful to mount heavy stuff like plasmas securely on dot & dab walls, 2" in the wall and the rest coming flush to the outside of the boards.

That plus anything that needs to be easily dismountable and leave a clean finish. Frame fixings on steroids.

[Roger Mills]

Or, how about this . . .

Use a steel plate (say 3" square) at each fixing position, and permanently set it into the concrete so that the top is flush with the floor. Use resin sockets in the floor - set down by the thickness of the plates. Drill a countersunk hole in the centre of each plate, in line with the socket. Use ordinary set bolts to hold the machine down and, when the machine isn't in place, use countersunk set screws to fill the holes. There will then be no trip hazard and no risk of crud getting in the bolt holes.

[ARW]

And rawlbolts hold my brothers two-post lift in place (with a little help from gravity)