Replacement door latch with 5/16" square drive

I have a broken door latch. A part similar to this one, where the handle has a square protrusion that fits through the square hole. The square drive is 5/16" on a side.

Neither the handle nor the latch have any brand markings on them. The house was built about 18 years ago and I assume they were some relatively cheap store brand available at the time. I would like to get a replacement latch so that the doorknobs in my house will continue to match, but I have purchased 5 of them so far, in a variety of brands from Amazon, Lowes, and Home Depot, and none of them fit. Even the one I linked, which says it fits a 5/16" drive, does not fit. It is lying. It even has a schematic drawing in the pictures that says that it’s 5/16", but when you buy it, the one that arrives has a 1/4"/9/32" hole, and a schematic to match. If you look at the comments on that page, there are several that point this out. For example “Package claims it fits 5/16 in. But the hole is too small and does NOT fit my door knob with 5/16 in. spindle.”

I have called two local locksmiths, and neither can seem to source a part. I’m sure they’re not thrilled to go to great lengths for something that costs like $10-15, but there it is.

Clearly there exist parts that match this one. Other commenters on the Home Depot listing desire them. Someone even took the trouble to draw a schematic that says 5/16" on it, which presumably they did not do just for fun. But either the inventory of them is so messed up or comingled with non-matching ones that they’re not possible to find or… what? Did they burn all the blueprints and kill the machinists who worked on them after my house was built?

Help me, SDMB. You’re my only hope.

If it wasn’t a successful product then the original may no longer be made. You’d have to measure any model you find yourself because the listed dimensions may not be accurate.

At what point will you admit defeat and get different latches and knobs? If you’ve put all this effort into it so far then you probably want to change all the latches and knobs in your house to match. That won’t be cheap, but once you finally get that completed I’m sure you’ll find the right size latch you want now to be available at several local stores, probably on sale for far less than what you paid for the new ones. So you might as well get started on that.

There are 20 doors in this house and a not crappy handle is like $50 or more, so I’m not dropping $1000 on this right now.

I have a not-matching handle left over that I put on for now while I continue the search.

The weird thing is that this product clearly exists. It’s just that what is shipped to me doesn’t match what’s on the web page. Like, the diagram included with the one that arrives correctly matches the actual size of the hole as 1/4" and 9/16".

An interesting point:

To make life more miserable, Yale Lock decided that we were not capable of measuring a 9/32” spindle with a ruler. After all 9/32” is .281” which is almost .312”, which is 5/16” and how many of those little lines can you really count on a ruler (Remember that this was a long time ago). So when you looked in an old Yale Lock catalog, the 9/32” square spindles are actually called 5/16” square.

I wonder if much of industry didn’t adopt this convention as this is what you seem to have found.

If you cut a round hole in the door, so that you can use a conventional latch, would you be able to find something that would work and let you continue to use the same doorknobs?

That’s odd. If you go to the manufacturer’s website for the PrimeLine E-2440 door latch, their own description says:

*Note #1: The square drive on this latch has a 9/32 in. opening and a 5/16 in. opening, but it will NOT accommodate 5/16 in. square spindles. The maximum square spindle size that this latch will accommodate is 9/32 inches.

I was able to find one here, but they want $59. If you have to have it, I would call them on the phone and discuss the specifics. The same vendor (www.allaboutdoos.com) also sells the PrimeLine E-2440 latch and on their website, they claim:

Diecast latch with brass plated face for old style passage doors; accepts 1/4-inch to 5/16-inch square shaft.

Try Google “door latch 5/16 spindle” (without quotes). I looked at the images, since I got a lot of noise. There were other latches, but they aren’t very specific on the size of the drive.

Tell them you’re a contractor working on a major project, and ask them to send you a sample.

If that’s too deceptive for your tastes, get a contractor’s license, bid on a major project, and then ask them to send you a sample.

That… is odd. I wonder if this is an Inside Diameter/Outside Diameter thing? I’m not sure how much larger the hole needs to be than the spindle, but surely not a whole 1/32".

I would be willing to pay $59 to fix this one door and have the handle match if that’s what it takes. But of course there’s no guarantee that this $59 one will actually fit either.

Do you have another door somewhere that you don’t care if the hardware matches the rest of the house? Like a closet door or something? Buy a new doorknob/handle for that door, then use the latch from the old hardware as your replacement.

Not really. Any door that doesn’t match is going to stick out and look weird.

I am going to spend some time looking for a handle from a big-name manufacturer (Kwikset, Schlage, etc.) that looks as close to the ones we have as possible, since this probably won’t be the last knob that fails.

Stupid question, could you take a grinder or belt sander and take 1/32” off 2 sides of the spindle?

Maybe. I don’t think the spindle is solid, and I’m not sure it’s thick enough to be shaved down and still be strong enough and intact.

It also has to go through the latch and then into the other handle, so there’d be a lot of slop at the other end or I’d have to shim it with something.

Are there set screws in the knobs? Any carpenter (or locksmith) likely has numerous spindles you could experiment with.

If it’s not a solid spindle, it’s definitely a cheap lock set. If that’s the case it may be press fit into the one side. You might be able to remove it, and use the smaller spindle with epoxy like Jb Weld. Pretty permanent solution, though!

The spindles and catches that I have are all +/- .268".

Alternately, file out the inside of the hub. It doesn’t look like there’s a lot of clearance around the diameter of the hub, but you don’t need much. Only 0.6 mm on each corner.

And it’s probably brass. Much softer.

I have to laugh at that article. It is steeped in the utter distain for one’s own industry in a way that only an expert can muster. It’s amazing how many poor decisions can be made over time for even the narrowest of design elements. Why standardize on a single threads-per-inch value when you can have three different values instead? (Of course this was done for vendor lock-in purposes, but that makes it even less excusable)

Yeah. I’d have to examine one to be sure, but I suspect there’s enough margin in the hub that you could file a corner right out to the edge. The hub will have a smaller diameter on its faces so that they fit into the carrier piece like a bearing. It should be slightly larger on the inside.

I might try filing out the hub. The one I have right now (the most recent attempt that has not yet been returned) is not large enough, but I think some of the others are.