I am wondering if anyone knows of a site or primer on repairing old style door knob assemblies. I have a 1929 house with mostly original glass or bronze door knobs and many of the assemblies no longer operate. Before we start taking them out, I wanted to review whats what with the insides and how one might fix them etc.
If anyone could provide any info I would appreciate it, thanks!
I am a locksmith by trade and I repair/rebuild antique mortise locks all the time. If you don't know what you are looking at, or are not super mechanically inclined, you may find it difficult to repair a mortise lock. There are so many different things that could be ailing it that I could not mention all of them here. I have seen hundreds of broken cast iron parts inside of mortise locks, as well as worn-beyond-belief brass or bronze parts. Broken or missing springs tend to be a fairly straightforward fix, but sometimes exactly how the original springs were set in place can be a bit of a mystery, or at least a challenge. When you open up the case, you can never be sure that what you are looking at is how the parts were supposed to go together. I have opened up countless locks and found that someone had improperly reconfigured the parts, and sometimes that's all that was wrong in the 1st place. Additionally, you may find parts entirely missing, if a previous owner decided to remove them, or lost them.
Now, for your house, directly. Hardware from 1929 could be a real challenge. A lot of the lock manufacturers by that time had switched to steel mortise bodies and steel internal parts. When you take apart one of these cases, parts can literally go flying, so watch your eyes! I have had a close call or two with an errant spring hitting me in the face. When these locks need service, repairing them can be almost impossible, unless you have donor parts. I keep in stock hundreds of derelict mortise locks for just this reason. If I can't repair the part, I can look through my locks to see if I have an identical one for parts (or sometimes complete replacement).
I strongly reccomend you veer away from the new reproduction locks that are on the market. These locks absolutely define the meaning of CHEAP JUNK. Your very best bet is finding genuine locks for replacements or parts. Find a trustworthy locksmith in your area who has been around a while and is used to working on old locks. He will have the expertise to repair your locks, and probably inexpensively.
Beyond all this, the most common problems I see with antique mortise locks are 1) broken springs, and 2) paint buildup. Also, make sure your locks are well lubricated. Use something light, like WD-40. Graphite is ok, but hard to get where you want it, and is very messy. It also never goes away. I have repaired mortise locks where the only thing wrong with them was that there was too much graphite buildup! Also, make sure your strike plate is still properly aligned to catch the latch (and the bolt, if you wish to lock it). This can change from year-to-year, or even season-to-season. If it's far off, remove it and reposition it. If it only needs to be adjusted a little, use a metal milling bit that you can chuck into a Dremel or a drill. Or, you can remove the strike plate and hand file it.
Andy wrote: "When you open up the case, you can never be sure that what you are looking at is how the parts were supposed to go together."
That's true but chances are that the homeowner would have access to another assembly from a working door that he can inspect as a proper reference point.