Self tapping screws?

[Dylan123]

I’m making a frame for a coal bunker door.

I bought some turbogold self tappers and glued the frame in clamps.

Tried to drive one of the screws in and it just stuck halfway and now won’t turn either way. (See pic)

I’ve tried my cordless, my mains and all my screwdriver heads at every possible speed.

I can probably get this screw out, but the question is, how do you use self tappers? I thought they were sharp and should glide through it.

All that’s happening is the head of the drill just spins.

bigger screwdriver bit for the drill?

no idea how to sort this

 

[freddiemercurystwin]

If it was me I'd attack it cautiously with some mole grips. I'd have drilled a slightly smaller than the screw sized hole in the horizontal member and then a smaller counter hole in the upright first, if only to save the wood from splitting.

 

[opps]

You have effed up the head. Try pliers to remove it.

Before screwing, drill a (clearance) hole in the top section of the wood that is very slightly bigger than the screw diameter. It will allow the screw to pass through. [If you try to screw directly through a bit of timber in to another, they push temselves apart if you don't have a clearance hole]. Then drill a "pilot" hole in the end grain of the timber below the top part. The pilot hole serves two functions. It reduces the risk of the end grain splitting and makes it easier to drive the screw in (thereby reducing the risk of camming out the head, or snapping the screw).

 

[Dylan123]

You have effed up the head. Try pliers to remove it.

Before screwing, drill a (clearance) hole in the top section of the wood that is very slightly bigger than the screw diameter. It will allow the screw to pass through. [If you try to screw directly through a bit of timber in to another, they push temselves apart if you don't have a clearance hole]. Then drill a "pilot" hole in the end grain of the timber below the top part. The pilot hole serves two functions. It reduces the risk of the end grain splitting and makes it easier to drive the screw in (thereby reducing the risk of camming out the head, or snapping the screw).

so do you mean like an exaggerated countersink hole? Enough for the screw head to get through?

then drill a pilot hole through that?

these are 80mm screws, I tried with wood screws before but it only went as far as the pilot - with a 3mm wood bit, I can only give about 40mm pilot max as the drill bit is only short.

will the screw keep going?

have I understood correctly?

 

[Dylan123]

If it was me I'd attack it cautiously with some mole grips. I'd have drilled a slightly smaller than the screw sized hole in the horizontal member and then a smaller counter hole in the upright first, if only to save the wood from splitting.

I don’t understand how this is possible.

the timber is 50mm by 50mm

I can drill the slightly larger hole, but the slightly smaller one below that, how am I supposed to drill a tiny 3mm drill bit through 50mm of the long piece? The drill bit is too small

 

[Dylan123]

I can’t move that screw with pliers, I have a screw extractor will try that

 

[Deleted member 174758]

Saw a slot across the top of the screw with a hacksaw or a Dremel tool and mini griinding disc and try to back it out with the biggest straight screwdriver you can get hold of.

What size screws are these? 5.0 x 80mm wood screws? If so you might want to try a 4mm pilot hole next time, 3mm is too small a pilot hole for a 5mm screw, but it also sounds as though your drill isn't very powerful. Long (80mm or so) HSS twist drills can also be had from various people on eBay

 

[big-all]

make sure you driver bit is pz2 and drill on low gear clutch to maximum number or drill symbol

 

[freddiemercurystwin]

I don’t understand how this is possible.

the timber is 50mm by 50mm

I can drill the slightly larger hole, but the slightly smaller one below that, how am I supposed to drill a tiny 3mm drill bit through 50mm of the long piece? The drill bit is too small

The bit will be say 70mm long, that gives you 15mm or something stuck in the drill so would give you enough to make a mark, then unclamp your two parts and drill the little hole however deep it needs to be, then reclamp your two bits together again.

 

[Dylan123]

The bit will be say 70mm long, that gives you 15mm or something stuck in the drill so would give you enough to make a mark, then unclamp your two parts and drill the little hole however deep it needs to be, then reclamp your two bits together again.

right, nice one. Could I not just make a mark and then just screw into that?

I bought these screws because they were self tapping. I didn’t think self tappers needed all this faf!

 

[freddiemercurystwin]

Sure you can just make a mark, but you need something long and very thin, a bit like a small drill bit ....

I daresay with a good drill and appropriate bit they'd be fine. As mentioned you may well split the end of your battens screwing into them without counter drilling. It's really not a big deal to counter drill, the next time you do a project like this it'll take practically no more time and will go smoothly - so no faff.

 

[Dylan123]

Thanks all. I favour a “have a go” approach At DIY. I’d be sunk without you old hands.

 

[freddiemercurystwin]

Countersunk?

 

[Dylan123]

Countersunk?

what I mean is when you drill a small hole with a large drill bit to recess the head. That’s what I thought was being got at. But now I realise that the long piece actually the screw doesn’t bite into that, and it’s like a hollow tube down to the other bit of wood. But the head of the screw tightens against the top.

I was getting confused but I googled it and I get it now.

I would have never have thought that’s how it’s done. I thought you’d just screw through both bits of wood.

 

[foxhole]

Self tappers are for metal, they look like wood screws .You used the wrong bit , requires pz2 anything else will damage screw head .Good job it stuck, at that angle it might have burst out the sides.