Fitting knob to mortice latch.

[MJP]

I've got a couple of sets of ceramic doorknobs to fit to mortice latches on internal doors.
The knobs are similar to this:

My problem is that the screwholes are on a circle whos diameter is significantly smaller than the diameter of the knob so I cannot screw the screws in properly, at right angles to the door. They go in at an angle. (The knobs I have are much more extreme than the pic).

This results in the knob being pulled slightly off line so that the opening/closing action is very tight - unacceptably so.

Things are made worse by the fact that I am fitting these to awful cardboard honeycomb doors which have already been hacked about previously for earlier latches.

Has anyone got any idea how these knobs can be reliably fitted so that I don't need to use two hands to turn them?

They've got me beat.

Martin.

 

[Doug71]

I have done a few knobs like that and yes they can be a pain to get everything lined up and working properly.

I find about all you can do is put all four screws in at an angle and use them to kind of adjust it until it is in the right place.

What latches are you using? The ones classed as architectural or double sprung generally work better although you still need everything to line up.

Will be interested in other peoples solutions?

 

[Gordon Tarling]

Try leaving all the securing screws just slack enough to allow the baseplate to float a little - it's worked for me in the past.

G.

 

[Doug71]

Also check that the spindle comes out of the knob squarely, if it is on an angle at all you will never get them working properly.

Sometimes the cheaper ironmongery is easier to fit as the tolerances are not as tight as on the better quality stuff so you get a bit more leeway but sometimes the cheap stuff is so far out it just won't work.

 

[MJP]

Thanks all.

In a way it's some consolation to discover that it's not only me who has this problem!

I'll try slackening off the screws as suggested and see if that helps.

Otherwise ....who knows?

Martin.

 

[Sgian Dubh]

A trick that's worked for me if the knob doesn't overhang the rose too much is to put the doorknob in place over the spindle, mark the centre of the screw holes in the rose, and remove the doorknob. Next, drill the pilot holes perpendicular to the door's face and put the screws in, either by hand or with a drill driver, whichever is to hand or appropriate. Take the screws out, put the doorknob back in place and refit the screws (usually) with a handheld screwdriver. The idea is that the screws will hopefully follow the same threaded hole they created earlier, and because the pre-threaded hole now already exists much less effort is required to simply refit the screw as opposed to the effort required to drive the screw into the bored pilot hole in the first place. A bit of wax on the screw thread can help too. Slainte.

 

[MJP]

Thanks Richard - this idea I will most certainly try.

Why, I wonder, do they make knobs which are so obviously tricky to employ anyway?

Surely the way to do it would be to have the rose and knob as separable items - fit the rose, then attach the knob to the rose.

Yet another example of items designed by folk who never have to actually fit them.

Martin.

 

[Terry - Somerset]

You may be able to use a cranked screwdriver - available as posidrive or slotted.

 

[pidgeonpost]

I've used this principle - works well.

 

[Sandyn]

I drill pilot holes then use a PZ1 X 250 screwdriver with suitable sized screws. The long thin screwdriver allows you to get better purchase on the screws in-line with the head.

 

[hlvd]

You need to tighten them all a bit at a time rather than one fully then the next.

 

[MJP]

Again, thanks folks - lots of good help.

I've tried slacking off the screws a bit and that seems to help a little so I'm hoping that wear will gradually loosen things up now.

I dread the thought of having to use a cranked screwdriver - I've got neuropathy and using a normal one is hard enough!

Martin.

 

[Sporky McGuffin]

Would something like this work? The tool goes into the gap betwixt knob and rose.

https://www.amazon.co.uk/Rolson-28910-Offset-Ratchet-Tool/dp/B0077LGRDO?th=1

 

[MJP]

Well yes indeedy it would!

- or at least it looks worth a try.

I had thought of trying a screwdriver tip in a standard ratchet but that's too long to get in the space but this tool look just the job. Reviews are generally positive too. I never thought of looking for something like this.

I've just ordered one.

Thanks Sporky.

Martin.

 

[Sporky McGuffin]

No probs. Wera do some lovely ones but they're a lot more money as you might expect.

 

[MJP]

Indeed so.

But since I'm only ever likely to use this tool for one session of doorknob fixing, I'll settle for cheap and cheerful!

Martin.