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Scunnered

Name That Screw

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Anyone know what you'd call the screw at the top? The squares are 1cm.

357jzfc.jpg

This came from an upright wooden chair, where it was attaching the seat to the back legs. I've got another one that's sheared across about half way along and I need a replacement, but I've no idea what you'd call it. It's probably 40 or 50 years old, so I wouldn't be surprised if such screws no longer exist.

Also, the one at the bottom came from the same chair. Is it just a standard wood screw?

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I think that sort of screw at the top is called a 'coach bolt', but I'm no carpenter. (The bottom one is a standard wood screw.)

Aha! That looks promising. It seems that a coach bolt is a bolt with a smooth bit at the top, and no taper; however Google Images leads to 'coach screw', of which Wickes has ones that look like this:

Exterior-Hexagonal-Coach-Screws_small.jpg

I think we're getting there. My problem now is going to be that mine is undoubtedly an Imperial Coach Screw [*] and nowadays you probably only get Metric Coach Screws. At least I know what to look for now. Thanks!

[*] There's bound to be a joke in there somewhere. 'A man goes into an ironmonger's and says "I'd like an imperial coach screw"...'

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Hex head metric coach screws are now the norm. Square head imperial for an authentic restoration may be obtained from here...

'Coach Screws Square Head, Zinc Plate, Self Colour, Metric, Imperial':

http://www.fastfixdi...ategoryID=59227

The bottom screw is a countersunk wood screw (ubiquitous).

Edit: Added source of square head imperial coach screws.

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Hex head metric coach screws are now the norm. Square head imperial for an authentic restoration may be obtained from here...

Thanks. The screws are well out of sight under the seat, so it doesn't have to be too authentic. May as well go for it if it's possible though.

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I'd love to be the sort of bloke that had a garage full of little drawers filled with every type of every hardware-living-thing under the Sun. But I'm not.

Not so long ago, you could go into your local ironmonger and there would be just such a man waiting there to solve your every problem. Now we've got goddamn B&Q, staffed by people who know nothing.

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Be careful here. Your photo shows a screw with an unusually long shank (the non-threaded piece), and it also looks to be non-tapered. That's possibly a dowel screw of some type. You need to accurately match the diameter of the shank, or the piece held by dowel action will either split (if the new one is too big) or be loose (new part too small).

If I were doing it, I'd fill both holes with a good filler (epoxy or polyester based) and drill again to suit the new screw. Coachscrews are usually available at the local ironmongers for a few pence.

Dowelscrew pictures

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Not so long ago, you could go into your local ironmonger and there would be just such a man waiting there to solve your every problem. Now we've got goddamn B&Q, staffed by people who know nothing.

That's very unfair. Last time I was in B&Q the staff observed that I was not young to be pulling around a barrow with lots of paving slabs on it. Having passed through the tills they showed an in-depth knowledge of conversational Punjabi.

p-o-p

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Be careful here. Your photo shows a screw with an unusually long shank (the non-threaded piece), and it also looks to be non-tapered. That's possibly a dowel screw of some type. You need to accurately match the diameter of the shank, or the piece held by dowel action will either split (if the new one is too big) or be loose (new part too small).

That's what was worrying me about the metric/imperial thing, so it was a bit of a relief to see that you could still get imperial ones. I've just applied a micrometer to it, and it looks as if the diameter of the shank is exactly 5/16 of an inch. I think I really need to show up in person somewhere where they've got a large stock of these things, but that's not so easy these days (my Yellow Pages doesn't even have an entry for ironmongers).

If I were doing it, I'd fill both holes with a good filler (epoxy or polyester based) and drill again to suit the new screw. Coachscrews are usually available at the local ironmongers for a few pence.

I was hoping to avoid any drilling, although I was toying with a fallback plan of smoothing out the threaded hole with a drill and then sticking in a bit of dowel and lots of glue. Wasn't sure if that would support the weight though. The new screw option's looking reasonably promising at the moment though, so hopefully nothing too drastic will be required.

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Be careful here. Your photo shows a screw with an unusually long shank (the non-threaded piece), and it also looks to be non-tapered. That's possibly a dowel screw of some type. You need to accurately match the diameter of the shank, or the piece held by dowel action will either split (if the new one is too big) or be loose (new part too small).

If I were doing it, I'd fill both holes with a good filler (epoxy or polyester based) and drill again to suit the new screw. Coachscrews are usually available at the local ironmongers for a few pence.

Dowelscrew pictures

Only the top fastener in that link is a dowel screw (threaded both ends, no head). What the OP shows is a coach screw which has a straight shank of slightly larger diameter than the thread. Consequently it's not too important if the shank is a little shorter than the original provided, as you say, it is of the correct diameter. If this is an old piece of solid wood furniture I would not use filler on it; it should be possible to obtain a coach screw of the correct size (although finding one with a high profile head like the original may be a challenge).

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Only the top fastener in that link is a dowel screw (threaded both ends, no head). What the OP shows is a coach screw which has a straight shank of slightly larger diameter than the thread. Consequently it's not too important if the shank is a little shorter than the original provided, as you say, it is of the correct diameter. If this is an old piece of solid wood furniture I would not use filler on it; it should be possible to obtain a coach screw of the correct size (although finding one with a high profile head like the original may be a challenge).

Yes filler is denifintely out, if you have to use a different size screw it should be drill, then glue and dowel, then re-drill.

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Some sort of an old coach bolt, I'd 'a' said, and ignored it. :lol: How slack am I ?!

28337_tm.jpg

You can still get them in That China. They're known, among other things, as chair screws.

Bit of a problem. Nowadays they're limited to use as railroad spikes. The smaller furniture-sized ones long superceded, no doubt.

And are consequently only available in sizes greatly exceeding my fully turgid genitals.

Yours is a 2 1/4" x 5/16" (I suppose about a No.18 or 20), so M8 would do.

Trick is getting it to bed down on the bearing surface (I'm assuming it's in some kind of a counterbored hole or pocket? That's the purpose of the raised head). Try a washer, maybe a bulldog one (the frilly-edged ones like you find on washing machines and the like)

Trouble is, going by the description, that rear seat joint on a chair is subject to the most humunguous racking and torsion, amplified by the tiny cross-sections.

Think of someone like Noodle, rocking back on the hind legs to stick his boots on the drawing room table and match up a blimmer.

It's not the screw that usually goes, it's the borehole in the far member where the business end of the thread grips, especially when the wood gets a bit old and carroty.

If it was my chair, and not an antique, I'd commit an atrocity just to be on the safe side, even if not going into end-grain.

Tee-nut fastener on the show side of the leg countersunk in a shallow bore (Forstner bit), veneered with a bit of scrap (if square-section legs, try lifting a flap with a sharp chisel. Bolt from inside the seat rail. Any old thing, on a washer.

Or one of them Swedish dowels (Bed-bolts) with the Allen-key hex drive head. Metal dowel part (can't find a picture handy) in leg across grain, hide as before, and pray to Cthuthlu that it doesn't compromise the leg strength at that point :lol:

Bore crosswise to meet and stick the turny bit in from the seat side as before.

But then I am a barbarian.

Seems an awful lot of fanny just for an old chair, though, don't it just?

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This came from an upright wooden chair, where it was attaching the seat to the back legs. I've got another one that's sheared across about half way along and I need a replacement, but I've no idea what you'd call it. It's probably 40 or 50 years old, so I wouldn't be surprised if such screws no longer exist.

Also, the one at the bottom came from the same chair. Is it just a standard wood screw?

Don't say you've lost the warranty card? Schoolboy error.

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buy a new chair.

fixing an old one makes you a traitor to the recovereh.

you should be ashamed. keep taking the flouride....you need dumbing down by an order of magnitude.

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Bit of a problem. Nowadays they're limited to use as railroad spikes. The smaller furniture-sized ones long superceded, no doubt.

And are consequently only available in sizes greatly exceeding my fully turgid genitals.

Like this?

npgfvp.jpg

That's a good 6½ inches, 7¾ including the head.

Trouble is, going by the description, that rear seat joint on a chair is subject to the most humunguous racking and torsion, amplified by the tiny cross-sections.

That's roughly what my mum used to say when I was balancing on the back legs. She was right, but it took about 30 years before it finally broke.

The hole seems to be OK; the screw was snapped across the middle. I even had to invest in a screw extractor to get it out (that was a joy to use - definitely a case where you need the right tool for the job).

Seems an awful lot of fanny just for an old chair, though, don't it just?

Yeah, but I can't bear to throw things out. It's hardly a valuable antique either, just a cheap kitchen chair form the 50s. It does come from my ancestral home though, so I feel obliged to make the effort. I'll keep a look out for a suitable screw for a while before resorting to anything more difficult (and probably beyond my competence). Thanks for the benefit of your expertise.

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Guest X-QUORK

Deliberate attempts at getting into the Most Boring Thread thread will be ignored.

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Deliberate attempts at getting into the Most Boring Thread thread will be ignored.

Once again I've been cruelly thwarted. I thought I'd got away with it this time.

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This is my sort of thread! :blink:

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Probably some weird imp. pitch too, so a modern thread will likely chew the wood in the hole where the old screw tapped it, won't coincide, so you're trying to get a grip in a load of wee ridges of very short grain.

So maybe the normal coachscrew, with the thread of the bit it's going into beefed up with a bit of epoxy/chemical metal (hot-wax the good screw and turn it into the the leg on its own (i.e. disassembled)? Or just go oversize. Like people were saying.

(B&Q for a few at 4x the price, no doubt, no point going to Screwfix for a bucketful. McDonald the Locksmith in Bread Street is one of those old-skool shops with the cubbyholes full of, well locks and things, but the old dudes in there ken their onions. But don't all wear brown shopcoats anymore. Dougie Murray's on Morrisson St just has a small amount normal stuff, wouldn't bother. And Bell Donaldson Steel tend to laugh in my face whenever I go in and want less than a cubic foot of anything like nails )

God, english is quite hard innit?

You could try taking a turn down to Sam Burns's Yard out the back of Musselburgh on the 'Pans road, there's the most godawful pile of shite to rake through there but it's practically free. Never know what's in the wreckage. I think they keep bits and pieces in the smelly caravan site office.

Or tout the good one round salvo places, E.A.S.Y. down Pilrig and Leith, or the guy in the old brewery on the road between Duddingston and Craigmillar, forget what it's called (everything, including the road, and this "computer" craps out if I try and make it do maps).

He's got cabinets full of unfeasible victorian ironmongery upstairs, like a Black Museum of Home Improvement. Must have loads of salvo fittings squirrelled away somewhere.

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  • 145 Brexit, House prices and Summer 2020

    1. 1. Including the effects Brexit, where do you think average UK house prices will be relative to now in June 2020?


      • down 5% +
      • down 2.5%
      • Even
      • up 2.5%
      • up 5%



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