Re: 1940's mortise lock, gripset & doorknob

My house was built just after the war. Most of the original stuff is still here, including the front door hardware. I know how to do most of what needs to be done here, but I just haven't dealt with mortise locks before, or really done much of anything with doorknobs beyond removing heavy tarnish from internal knobs and re-installing them.

My front door has a mortise lock, with a gripset on the outside and a knob on the inside. The deadbolt works fine, but the knob doesn't: I have to turn it back and forth repeatedly before I can actually open the door, which drives me nuts. What I don't know is where, exactly, the problem lies; is it in the mortise mechanism itself?

Also, I'd like to replace the knob, and I think I need to replace the gripset, too. KNOB: it's really small and smooth, and set fairly close to the door, which makes it difficult for most people to grasp (let alone twist it back and forth, and back and forth, and back and forth, just so they can get outside). GRIPSET: the screw which attached the bottom to the door apparently fell out, and is now gone; with the base no longer attached, of course, the grip is less securely attached to the door, and I'm sure the small movements are wearing away the wood around the screws at the top of the grip, too. These screws have decorative heads and, after much searching, I've concluded that I'm just not going to be able to find one that matches the others.

So, my questions are:
(1) Is the difficulty opening the front door caused by a problem in the mortise mechanism, or is it somehow a problem with the knob? (If it's the mortise, I'll go for repair over replacement if I can.)

(2) Assuming I replace the knob and gripset, do I have to replace the whole mortise mechanism, as well? Or is it possible to replace just the external hardware, and keep the internal stuff as-is?

I'm sorry if this is difficult to follow. I find it hard to explain a problem when I don't know what/where the problem lies.

Thank you to anyone who reads this and responds!

 

1. I presume the difficulty operating the inside knob is due to either a worn spindle or the grub screws are not tight enough to prevent the knob from repeatedly turning.

If the key cylinder operates properly (locks and unlocks correctly) the lock is probably okay.

You could replace the inside knob with a lever handle, but you might need to replace the spindle too.

2. If you decide to replace the knob and thumb press gripset, you'd be advised to replace the complete mortise lock as many modern parts are incompatible with old stuff.

if you decide to replace the parts, look for Baldwin hardware or Emtek hardware. Baldwin is probably better but is also significantly more expensive, because they guarantee their products for life.

 

I assume the knob will not retract the latchbolt sufficiently to permit the door to open every time?... with the door open, can you push the latch in all the way with your thumb? If not, the lock would need to be dismantled to see what gives.
If yes, next see if you can remove the knob by removing the set screw ("grub" screw....clever term, Global) and either pulling the knob straight off or, more likely, unscrewing it CCW. The steel spindle is usually "split" along it's length...remove both pieces. Thru the hole in the door you can now see a square brass hub, see if by using a large screwdriver you can turn the hub enough to withdraw the latch completely.

If not, see above: complete dissassembly. If yes, re-insert the the spindles, hooked half 1st (hook away from hub) then slide the 2nd half in. Re install knob & tighten set screw as tight as you can muster.

If you do end up taking the whole thing apart, lube all moving parts (except key cylinder) with lithium grease (or similar)....does wonders.

Ditto Global's advice, you generally can't get replacement parts for these old locks.