Screw trouble for door knob

11 Dec 2007
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United Kingdom
Let me know if you need a picture to show better what i'm about to describe...

I've had a couple interior doors off for painting & the plan was to change the door knobs on them from brass to silver.

Easy ... we thought.

Can we find door knobs to fit on the existing screws? Can we not! Either the hole is too small or too big.

I measured the end of the screw as best i could & it's 4mm across i would say. Went in to town today & put it against an M4 screw (i assume the 4 means 4mm? Don't crucify me as i'm terrible with this) and my screw looks thicker, so i then put it against an M5 screw & the M5 is thicker than mine.

I tried both the M4 & M5 in the existing door knob. The M4 just rattles around whereas the M5 initially goes in (a very small amount, like only just) but wont turn as it's too thick.

So since our screw seems to be neither M4 nor M5 we need to find out what it is & if it's possible to get a door knob to fit.

Failing that, with my limited (non existent) DIY knowledge, we need to get a new door knob & somehow make it so the screws that come with it fit the holes & don't rattle around or refuse to go in.

Help very much appreciated :)
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not that simple it will probably be imperial
you have whitworth american fine metric to name a few all different you have different thread pitches
you need to take a screw with you and find a nut it fits
what do the handles and plates look like ??
Why do you need to reuse any screws? Can't you fit a whole new doorknob set, with it's own new screws?
Yes we could fit a new doorknob set. We picked up a set. The screws either rattled away in the existing hole or they were too thick for it. Not really sure how to work around that so figured it'd be easier (i thought at the time) to get one to fit the existing.

As for what the whole thing looks like...

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Failing this we could always paint the door knob silver, but i've a feeling it would have to be a specific kind of paint..?? And would you need specific primers too if that's the case?
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Oh it's a fixed door knob. Silver knobs are ten a penny, just buy new ones. Paint would wear off in no time. You can either buy a fixed knob similar to the existing one (look up cabinet or cupboard knobs), or get ordinary knobs that are attached to their own rose plate, which you can just screw to the door. You can also use traditional doorknobs with a Taylors spindle:
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i am thinking its a hollow door ???
so possibly a bit off threaded bar ??
It doesn't feel like a hollow door to be honest.

And we ordered in new door knobs today. My wife said it was cupboard door knobs she ordered with these doors being a cob size anyway.

These new knobs like the other ones we ordered in, don't actually fit. A common problem is that the screw that comes with them will enter the existing hole but then the head gets stuck & wont go down all the way.

I'm a bit weary about drilling the hole bigger because i don't want to end up creating a bigger problem by drilling too big & then the head just shoots through completely, lack of confidence really, which is why we were looking at something that will just fit straight away.
the thread pitch is different they wont fit by doing anything other than change the thread to a compatible thread so take the old handles and bolts place them in a drawer and start again
or go to your local hardware store and ask for a length off threaded rod or 2 separate bolts long enough for your task
So what would you suggest (start again) since the new screws that come with the new knobs wont go through the holes properly.

I guess since the screw head is too big for the hole that the hole is going to have to be drilled out with a bigger bit, but how do you drill out enough for the new screw to fit down without drilling too far & ending up causing yourself a problem?

Or would you take a different approach?

I'm well aware i'm asking dummy questions here, but having never done anything like this before really...
ok if you take the new knob and screw it to the door will it cover the screw head for the other knob and sit flush
and will the second knob do the same ??
if so you have 1 choices to make the hole bigger for the correct thread size
you then either back to back the knobs offset to cover the heads
or a single threaded rod to do both in line back to back
drilling too big & then the head just shoots through completely,
That's what washers are for!

but how do you drill out enough for the new screw to fit down without drilling too far & ending up causing yourself a problem?
Drill out the hole so the shaft of the screw fits in (you have a set of drills, right? Work your way up to the right size hole. If the screw almost fits already you may be able to force it through like a woodscrew). Then drill a larger hole about a quarter inch deep so the screw head will sit below the surface. The door is thick. Surely you're not so clumsy that you think you might drill the entire way through the door by accident?! If too much shaft ends up sticking out of the other side, saw off the excess with a hacksaw.
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:whistle::whistle::LOL::LOL: Oh dear.

I actually took a look myself at this one to see what was going on after leaving it with my wife & just relaying everything across really.

Turns out we simply just need a longer screw.

What she was telling me was that the new screws don't fit & that the nuts wont go through the holes & the screw heads wont go through the holes.

Turned out they wouldn't go through the holes because she wasn't putting any force in to it. Give it a little persuasion & they went in fine enough (& were able to pull back out ok). The screw itself was a 40mm & this is why it wouldn't fit - we needed something like a 45mm. I told her to pick up a 50mm & we'll go from there.

50mm worked out perfectly fine.

Alls well that ends well. Thanks :)

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