I'm trying to fit 150 year old knobs to doors with old 6" mortices. These knobs are quite heavy and don't have internal springs but are free turning. The mortices are old but I've taken them apart and cleaned and lubricated them and they have a fairly powerful spring.
No matter how hard I try to make sure the handles and mortice are all properly in line I always get the same problem. When I tighten up the screws holding the second knob to the door, I always end up that the mortice will no longer return because something is binding.
What am I doing wrong? Is there a technique to this?
Obviously things are shifting when you tighten the fixing screws. I assume you have tightened down the plates between the door knob and door before you tighten the handle. Try doing it the other way round, have the plates loose, tighten the handles (so everything moves to where it wants to be) then fix the plates. Note fix them where they want to go not where the old fixings holes say...
I am assuming these are round knobs with an integral rose and that they operate the lock by a square bar that passes through the lock and fits inside each knob. If that is the case, have you checked that the square bar is not too long? If it is, it will force the knobs outwards, against the rose, causing binding.
The knobs don't have a separate plate. The knob and the plate are connected together with a free-turning joint. There's a plate that screws over the top. This is difficult to explain so here are some pics:
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I suspect that something is moving - possibly due to the fact that the screws have to be driven in at an angle.
In that case, it sounds as though screwing the rose to the door causes a misalignment. Possibly the two faces of the door are not completely parallel. If the handles and lock work when one is on, but not the other, one option could be to replace the single square bar with two pieces of bar. Each should be long enough to fit inside one handle and to reach to the centre of the square hole in the lock mechanism. Obviously, that will need careful measurement, but it will mean you only need to align the lock with each handle individually, rather than with the pair.
I'd be inclined to tighten the screws a tiny bit at a time until the binding starts, then ease off and put a shim of some sort under the plate that screws to the door near the screw that seems to cause the trouble, then retighten. It probably only needs a piece of thin card. If the bar is a really snug fit in the handles I'd consider reducing it very slightly with abrasive. If you press the plate with the screw holes to the wood gently, then feel all round under it with a feeler gauge or something you might be able to figure out position of the place where it needs packing.
I had this problem with cheapo plastic knobs and the modern tubular latches, im only using them on my aviary doors into the individual flights, wanted something that would slam closed and be openable from inside... unlike a bolt as usually used, but had to be cheap due to the number used,
Anyhoo, i had a hell of a time getting them bind free at first, in the end i made up a drilling template, on a piece of 12mm ply i drew round my knob (and posted it to the queen... erm, where was i :) and marked the screw holes,
Then measured from the knob plate outline to find the exact centre, i drilled the screw hole markings with a counter sink drill (reason in the next paragraph or 2), and drilled out the centre so it was just smaller than the square bar,
Hammered a square bar through the centre hole doing my best to ensure it was going through straight,
To use my new knob drilling template, i push the bar through a frame.. and thus through a latches square hole, line it up so it is roughly in the middle (there's always some wiggle) then using a hinge drill i drilled the screw holes, The hinge drill is a spring loaded drill bit inside an outer metal sheath, sold for kitchen cabinet fitters mostly,
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you just press the rounded nose of the bit into the hole (hence the countersinking) start the drill and press, drill bit is pushed out from the very centre of the guide part, and drills a small hole into the wood of the door so a screw goes in perfectly centred.
Do the same the other side, and 9 times out of 10 when you mount the knobs, it's all bind free (the tenth one is usually suspiciously free turning, then you notice you forgot to insert the square bar, as you'd left it in the template)
The issue normally is that the angle inside the square bit gets fixed and if the knob is pretty snug in its receptacle it binds. In the case I had I ended up finding knob sets that just sat on the square bar and did not have screws at all, then it worked. Brian
Thanks for all the advice folks! A combination of grinding the bar down a little, getting the wife to hold knob and tightening screws gently seems to solve the problem. I love Gazz's template - next time I have more than one to do I'll consider that,
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