Tips on removing screws stuck in metal plating.

[Mikeandvan]

Well, there were about 40 bolts still stuck, banging them with a hammer and then trying again with the impact driver, and copious amounts of wd40 helped shift half of those. Got about 20 stubborn buggers left, bought a disc cutter and cut the tops and bottoms off, on the one's I could reach anyway, then snapped a few drill bits trying to drill these last bits out, then went and bought a stronger drill bit, snapped that, what a bleeding drag, just as well I've got 3 days off to do this!! I think the easiest bit will be laying the new plywood, fingers crossed. The trouble is that the bolts go into metal plate rather than wood, so only the original holes can be used. This has cost me £370 materials, plus the disc cutter, but now I've not one realise they're handy. So once the last bits of screws are out tomorrow, just have to lay the ply - which was cut to size, then drill pilot holes in the ply for the bolts, do I need to countersink these too? Bloody hell, what a time consuming exercise, still beats lockdown boredom. Was thinking lay ply first then drill up through the holes from underneath the van to save on time marking out where the holes are? The bolts are 5mm wide, what size hole should I drill for that, bolts are countersunk head with a flat top (philips drive) Must be tight as the ply has to be absolutely firm, it takes a lot of bashing.

[Pigmy Pony]

Fixing through the ply into the steel (as it was before will make a firmer job than coming up through the steel and into the ply. Also if you did it that way round you would have to make sure the screws don't break through the top surface of the ply. I know you know this

For about 3 quid you can buy a countersink bit, which has a grub screw on the side which tightens with a small Allen key, so you can fit small hss drill bits into it. Get a few hss bits, about 2mm, probably about £1 each, and you can get though the ply and the steel easily, with the holes nicely countersunk. That way the screws will be recessed neatly with no splits in the ply.

[struth]

i would as said above use steel screws countersunk that way.. try and mark lines on the wood where the channels you want screws to go are/ i used old wood as a template but the screws need to go into fresh holes. m8 size is big enough. once down it wont move

[walpurgis]

Use stainless steel screws and you'd be able to take up the floor again if need be.

[Mikeandvan]

Fixing through the ply into the steel (as it was before will make a firmer job than coming up through the steel and into the ply. Also if you did it that way round you would have to make sure the screws don't break through the top surface of the ply. I know you know this

For about 3 quid you can buy a countersink bit, which has a grub screw on the side which tightens with a small Allen key, so you can fit small hss drill bits into it. Get a few hss bits, about 2mm, probably about £1 each, and you can get though the ply and the steel easily, with the holes nicely countersunk. That way the screws will be recessed neatly with no splits in the ply.

I meant drill under the van for pilot holes, then drill in and screw in from top, but I've since realised spray will do the same job! Its just so I know where to drill holes in the ply, as I need to use the same holes already in the metal plate of the van box. What I'm using is bolts btw, as that is what the holes are made for.

[Mikeandvan]

i would as said above use steel screws countersunk that way.. try and mark lines on the wood where the channels you want screws to go are/ i used old wood as a template but the screws need to go into fresh holes. m8 size is big enough. once down it wont move

Bolts are M5, or you mean m8 for the countersunk bit?

[Mikeandvan]

Use stainless steel screws and you'd be able to take up the floor again if need be.

No, this is good for 5 years! AKA until the van croaks it.

[Pigmy Pony]

Ok, I see what you mean. But how about this: Gun grade fixing foam (not expanding foam!) Apply in roughly 1" thick lines spaced about a foot apart, leave alone for 5 minutes then put ply on it. If your ply isn't dead flat you would need to put some weight on it for an hour, by which time the foam will have gone off. Suitable ballast might be your Charios and A/N speakers Then maybe half a dozen or so fixings around the edges.

Some plasterers use this to fix boards to walls.

Believe me that foam is pretty effective, and only costs about a fiver per tin (2 tins would be plenty) and a foam gun (about £10). I get mine from Magnets (the kitchen firm) but there will be other places. If you're not confident about it (I would be) you can always add your nuts and bolts method.

[Mikeandvan]

Ok, I see what you mean. But how about this: Gun grade fixing foam (not expanding foam!) Apply in roughly 1" thick lines spaced about a foot apart, leave alone for 5 minutes then put ply on it. If your ply isn't dead flat you would need to put some weight on it for an hour, by which time the foam will have gone off. Suitable ballast might be your Charios and A/N speakers Then maybe half a dozen or so fixings around the edges.

Some plasterers use this to fix boards to walls.

Believe me that foam is pretty effective, and only costs about a fiver per tin (2 tins would be plenty) and a foam gun (about £10). I get mine from Magnets (the kitchen firm) but there will be other places. If you're not confident about it (I would be) you can always add your nuts and bolts method.

That sounds preferable, not sure the speakers would be heavy enough though, this ply is seriously heavy itself. Anyway, spent another hour today getting rid of remaining screws, about 5 i had to leave in and drill new holes. Then finally give a little clean up and put the ply down, only to see it had been cut wrong, hahaha, what a ****! When I bought it i hadn't taken up the old ply so didn't realise it has to be cut to the the metal bars below so each end of ply sits on a bar and is secure. So had to drive an hour away pick up one more £80 sheet of phenolic ply, then drive 20 mins to cut it, what fun. Now its all down and fits real good, but its too dark to put bolts in, and I bought the wrong bolts anyway, as I discovered this morning, to be honest was hard to know. The bolts I need - same as old ones have a sort of slanted thread, they go straight into metal plate and don't need a nut, the fit is very tight. I tried with a regular bolt of the same size and it was tightish but after removing it saw that the thread was ruined, so over time it might loosen, may'be not, but now the ply is down I can take my time and search for the right bolt, the ply is fine as it is, very tight, but needs bolts, to make sure it is all level, so that furniture can be slid easily over it. Do you know what these bolts are called?

[Mikeandvan]

These are the bolts, old one is obv the rusty one! Notice the ruined thread on the new one, bottom of shaft.

IMG_20201126_203858788 by [url=https://www.flickr.com/photos/145505522@N02/