Previous owners had fastened down an inspection chamber lid on the patio, but the screws will not budge. Tried numerous applications of PlusGas, and it does disappear down the sides of the screws, which later still refuse to move at all.
Apart from keeping on with the PlusGas, are there any other ways of persuading the screws to turn? (Last resort: drill them out...)
The cover and sample screw can be seen here:
I've found Plusgas and all the other so-called "releasing agents" to be totally useless, to be honest. This looks like a job for an impact driver. I'd be reasonably confident about getting them out with one of those, having previously had consistently good results with them.
I was having trouble getting a screw loose on a bracket what I did was use my cordless drill on a low speed low torque setting and increased gradually so it wouldnt strip the head. I was quite surprised that it loosened it, maybe just luck but it worked.
I would have thought an impact driver after lots of Plusgas or similar.
Blowtorch on the screws first? Then insert screw driver and tap the handle with a hammer before attempting to turn them. A screwdriver with the blade the same width as the screw helps, especially one with a long shaft as well.
And if you need more leverage to turn the screwdriver, use an adjustable spanner tightened down onto the flats.
Despite others here swearing by blowtorches, I've never been successful with applying heat. I find whatever is binding steel against steel simply gets stronger. Possibly the similar to cold welding, but given the temperature more efficient.
On the other hand I've been more successful at applying shock, such as the combination if direct impact and turning action through the use of an impact driver.
I've often resorted to the careful drilling of a screw or bolt where it's sheared through binding and rust.
In the OP's case, I doubt the screws are of importance given the weight of stone.
At some risk to the stones, hot gas flame - ideally a fine very hot one to heat the screw red hot. That will usually crack the rust, but in your case, it *may* crack a stone too.
AND assuming there's not plastic or rubber seals present (saw someone else's post).
Kill or cure then...! Brian
I had the same problem with a cast alloy cover on a round plastic inspection chamber. Possible galvanic corrosion between the steel screw, alloy cover, brass insert, in that particular case.
I drilled them out.
I definitely agree in this case. However it is remarkable how exhaust fasteners come loose if you take them up to red heat with a gas axe.
Are they steel screws look more like Brass ones doesn't seem to be any colouring like galvanising or rust apparent and they don't look stainless either?..
Yes, they do look like brass. I do have a large 'persuader' screwdriver that seldom refuses to turn a screw, but the blade is not quite as long as the screw slot, and none of the screws has shown the slightest movement (yet).
Having given them several soakings of PlusGas, will try again today.
When you say "the flats", you mean the screwdriver blade, presumably, to provide torque on the horizontal plane?
Will give that a try...
Lets open a book re the chances of them being wrung off;-(..
Good point! I've been wondering how removing the screws will help the situation, unless they are fastening the lid to the frame in some way.
Supposing I got the screws out. How does that get me nearer to lifting the lid (unless there I have a lifting gadget that can be screwed in in their place)?
I don't see any other solution, so if I then can't find such a gadget then the cover will be immoveable - unless perhaps if I somehow remove all the filling that's in the lid find something to provide sufficient lifting grip.
Numerous applications of PlusGas and Impact Driver* did the trick!
The 'screws' are actually 1/4" dia 2" bolts with a circular slotted head. Cleaned the gunge off, applied silicon spray to thread and bolthole and replaced them.
Looks as though the bottom 1/2" of the thread screws into a flange projecting from the side of the chamber, but what I still need to check is whether or not the upper part of the thread engages with the lid itself after unscrewung from flange. If it does, then perhaps there's a handle of some kind that could screw into that (or try tying rope round bolt head, but head isn't all that wide).
What might do the trick - if it exists - is a lifting spindle with spring arms at the end, that could be passed down through the bolthole until it comes out of the lower edge of the lid, at which point the spring arms would shoot out and provide lifting capability. (Once lid lifted out, retract arms to retrieve spindle.) But probably not enough clearance between lid and chamber flange for arms to operate.
Tomorrow will get a screw out and see if it still grips inside the lid on the way out. Too exhausted to do any more today...
In the meantime, anyone know of lifting gadgets for these situations, please?
(* Draper kit; head setting for unscrew quite ambiguous. Trial and error...)
Unlikely I would have thought at that would interfere with the screws clamping force.
Tim
Someone provided a link to 'J' keys on the Screwfix site a few days ago. A couple of pairs of those - and two people to operate them -should do the trick.
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