Doorknob keeps falling off

I have one of these antique doorknob sets on my apartment door in my house.





One of the doorknobs has fallen off repeatedly since I have had this house. It got so I stopped closing the door all the way - I just left it open so then I can pull it open by grabbing the door itself rather than the doorknob. But recently I thought I had tightened the screws up for good so I started closing the door again.

I've examined the doorknobs and the spindle they go onto, and do not see any stripping. If they're stripped, I can't tell. Both ends of the spindle look exactly the same to me, in the same condition, but only one doorknob falls off. So even though I see no evidence of stripping, stripping is the only explanation I can think of for why one of the doorknobs keeps falling off. Since I don't see any stripping, I am at a loss to explain why one of the knobs keeps falling off and either trapping me in my apartment or outside of it.

Can I go to a big box store and buy a brand new doorknob to replace one or both of them with? Or a brand new doorknob set? Would that solve the problem? Or is that not even possible because even if a new doorknob set is in the same style, the new doorknob set won't fit. Or maybe the new doorknobs made in this style are even worse quality? Sometimes older stuff is better than the newer stuff.

I don't want to get into drilling new holes in the door & the door frame and mortising anything out. I just want the doorknobs to not fall off anymore because I want the door closed, and I don't like getting trapped in my apartment. Took me close to an hour to figure out how to get out this morning, and that was after I had already spent 20 minutes trapped outside - I thought I had fixed it, closed it from the inside to test it out, and got trapped again, this time without the masonry tool I had used to open it from the outside. Eventually I discovered a spoon handle fit perfectly and would open it from the inside.

So what's the best solution without replacing everything - the latch, mortising the door frame, etc...

Can I replace one of the doorknobs with the exact same type of antique doorknob? Would that solve the problem or no?

If I replace the spindle, would that solve the problem, yes or no?

There's a thread about this from 2018 where the person said they bought a brand new doorknob, didn't solve the problem, I don't know if it was the same kind of doorknob or a different kind.

Interior doorknob won't stay in

Would loctite solve this problem for this exact type of doorknob set?

I don't think I have the tools needed to drill holes in the metal spindle - not sure if I have anything to hold the spindle down with while drilling into it. I've got some clamps but they might not work for this type of thing. And even if I could drill holes into it, I'd then need to find longer screws that fit just right.
I don't have a pedestal grinder, don't know what that is. Don't know what an allen wrench would have to do with this either. Never heard of 'grub screws'.

If that photo isn't enough, tell me what photos you need.

 

Do you have a short version of your story? Maybe just your question.

 

The spindle may not be the correct size. https://www.locksmithledger.com/door...ssive-hardware

 

How can it not be the correct size? It fits in the door with no gaps.

 

No. I went out of my way to explain my question in detail, so nobody could say "you haven't provided enough information." You should be able to take whatever you need from it. There's no need for a response like that - it's a little insulting.

 

i was referring to the thickness. The article I attached describes how various spindles are sized differently.

 

I read your link. So this implies it could have been poorly designed in the first place, and this issue happens with all the doorknobs produced by this company back whenever they produced them?

 

Is there any mention of a set screw in that manifesto? Because you probably need to tighten them. Or as mentioned, the spindle was once replaced with the wrong size.

 

I've tightened them many times. It doesn't solve the problem. There is no way to tighten them tighter than I already have done previously. They can't be tightened any further. The one doorknob keeps falling off anyway. I explained that along with everything else. Then I get accused of providing 'too much' information' even though it's not enough information, apparently. Yes, they are setscrews and yes I have already tightened them. That is the obvious thing to do, and that's what I did the very first time this happened, and every time since then. It is not solving the problem. The setscrew wasn't loose in the first place. Every time it falls off I put it back in place and make sure it's as tight as possible. I check it every once in a while, and it's still tight. Still falls off.

This is only happening on one doorknob, not the other one.

Setscrews are mentioned 7 times in the link posted by 2john0248.

The setscrews are flush. They cannot be tightened any further than that. There is nowhere deeper for them to go. The doorknob still falls off all the time.

 

FYI:
"Set screw" and "Grub screw" are the same thing, the former used in USA and the latter in other English speaking countries. Some use a slotted screwdriver (yours), others use Allen (hex) wrenches, etc.
You've said the set screw is tight but the knob still comes off. The knobs should be internally threaded and only go on by screwing them onto the spindle. It sounds like your knob is just sliding off without having to unscrew it, correct? This was a common problem with residential grade mortise locks back in the day. It was very easy to cross-thread the knob when reassembling, and continued use eventually allowed the knob to slide off. The stripping usually happens on the spindle because there are threads only on the 4 corners, but replacement spindles (widely available back in the day) were sometimes hardened for durability, in which case the interior of the knob became stripped.

If you'd like to fix rather than replace, I'd first verify the set screw is actually impinging tightly onto the spindle. So with the knob removed, does it screw well into the knob hole easily? Assuming it does, and assuming the other knob has no problem, that is. you can loosen it's screw and unscrew the knob from it's end ok.

Mark the aprox. location on the bad end where the knob normally rests, and mix up a dab of JB Weld (not JB Quick) epoxy and poke it in the knob and set screw hole. Better to get too much, you can always wipe off excess.
Assemble to the mark, tighten set screw well, let it set at least 24 hours. When reassembling the other side, I'd put a drop of Blue Loctite on the set screw for good measure. As far as substituting Loctite on the bad side instead of epoxy, I'm not sure how well it would conform to the open spaces around the spindle, it might actually do better, tho if I were to try it, I would use the Red Loctite. It sets up within seconds tho, so you'd need to be quick.

What do you think, ThisOldMan?

 

I agree. Theadlockers are intended to secure 2 pieces of metal already in contact. Short of a boroscope, there’s no easy way to determine the condition of the threads in the knob. J-B Weld is the way to go for repair.

Someday the knobs/spindle will need room be removed, so I would not recommend red Loctite on the remaining screw. Red Loctite takes a lot of pressure (not likely with a screwdriver) or heat (not advisable in a home) to break loose. Here, I recommend sticking with the blue. If that doesn't hold up, it's time to replace the knobs and spindle.

Keep us posted as to what works, or doesn't.

 

Yes, with the knob removed, the setscrew screws into the hole easily (but not too easily). It fits the way it's supposed to.

This does happen, after I've screwed it back in place tightly, eventually it slides/falls off anyway even though I check it for tightness periodically.

So I need this: https://www.canadiantire.ca/en/pdp/j...-0383760p.html

Definitely not this: https://www.canadiantire.ca/en/pdp/j...-0383761p.html

Does the brand matter, or could I use something else such as this: https://www.canadiantire.ca/en/pdp/p...-0383825p.html

The other knob does not fall off so I am not planning on using any product on that end because as ThisOldMan says, someday I might need to remove it for some reason, so one end should remain removable with a screwdriver.

 

The Permatex epoxy should work fine too, I just have more experience JB Weld. You may have a slight advantage with the Permatex epoxy, because IIRC, when mixed, the Permatex is a little bit thinner and so may more easily be applied inside the knob. Any epoxy that doesn't set up too quick should work.

And I did suggest BLUE Loctite for the set screw on the "good" side......Blue is non-hardening, and designed to be serviceable. But, like you said, if it ain't broke, why fix it? If you've got some on hand, doesn't hurt to use a drop, but not worth it to buy a new tube, just for one drop.

 

Speed reading fails me yet again.

 

I used Permatex, a few days later the doorknob fell off again. Tried gluing it again with Permatex, this time I used more and spread it more thoroughly, but after a couple of weeks the doorknob fell off again. Gave up. Went to an antique store to see if they had a spindle with setscrew holes in it because I figured that's what I needed. The guy said "no" and was reluctant to dig through his merchandise to find me one that was in good condition, but eventually I got him to show me some. He brought out 3 sets, none of them with spindle holes. Finally the problem became clear. One of the sets he brought out, you actually screw the knob onto the spindle, and it stays in place. My set must have been totally stripped, because you can't do that with mine. There's no useable threads apparently. There's threads for the setscrew, but the threads for the knobs are totally stripped. With the original set, you don't screw the knobs on, you push them on, and they're supposed to stay in place by catching the spindle threads - I think this is a poor design. With the new spindle I bought, even though there's no threaded holes in the spindle, screwing the knob onto the spindle and then screwing the setscrews in place is enough. Cost $10 which included a knob because the knob I used Permatex on is unuseable now since the setscrew is glued in place forever. That's a better deal than buying a new glass doorknob set at Home Depot. The brand new ones aren't even as good as the vintage ones, based on user reviews - they become defective more quickly than the vintage ones.

As I was leaving, he showed me another spindle. It had holes in it, like I had been asking for. So they do exist. But the one without holes that I bought is good enough since the threads are in good condition. It's working like a charm so far, knock on wood

 

Glad you found a permanent fix. The spindles with threaded holes for set screw used washers between the knob and the thimble mounted on the estucheon plate (sometimes just a raised area) to adjust for differing door thickness.

And thanks for posting your solution!