1950s Chrome door lock knobs don't fit

[MickeyCaddy]

Well, this is disappointing. For my 1955 series 62 sedan, I ordered four (4) chrome door lock knobs from Caddy Daddy, guaranteed to fit "1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 Cadillacs".

The knobs arrived today, and the diameter of the threaded hole on the bottom is twice what it should be. The knobs simply slide on and off, and flop around on the threaded lock rods.

Has anyone had this experience? Can't imagine how this could occur.

Michael Chanslor

[Clewisiii]

On the left are the metal chrome lock knobs from my 1961.

On the right is a set of chromed plastic lock knobs that was supposed to be a correct aftermarket replacement. They are nothing alike.


Here you can see how far the correct knob should thread to the rod.


Even if the aftermarket would thread on, it would have to go on a long way due to it's increased height.


The threaded shaft is a 10-24

[MickeyCaddy]

Clewisiii, thank you so much. This is valuable information that I couldn't find anywhere else. The pictures helped a ton, and now I understand what I'm dealing with.

[MickeyCaddy]

Does anyone know if 1955 Eldorados and Fleetwoods were shipped with chromed metal door lock knobs, but entry-level Series 62 sedans (like mine) came with cheap-feeling plastic knobs? I've been unable to learn what the factory configuration was; and unable to find any chrome knobs that fit my car.

After the first set of chrome door knobs I bought didn't fit, I returned them and bought several samples from various suppliers, including a few from different years. They all fit the same as in the pic I posted above: the hole was almost twice too big.

I then bought a "Nut & Bolt Thread Checker (Complete SAE/Inch and Metric Set) - 26 Male/Female Gauges - 14 Inch & 12 Metric", but none of them even came close to fitting the lock rods in my doors.

When I acquired my '55, I bought a set of black, cheap-feeling, semi-soft plastic knobs which screwed right on. I think I paid $10 – $15 for all four. But I wonder if those are even threaded; after turning them down to the proper height, they can still be turned more but they don't get any lower.

My Dad worked for GM and was given a new Buick, Oldsmobile, or Pontiac (his choice) every year, but I can't remember exactly what GM door lock knobs were like back in the '50s. The samples I purchased look and feel familiar to me, probably because some of them are similar to GM cars of the 1960s. None fit my car.

I'm at a dead end; wondering if anyone has an idea. The cheap knobs I have work, and no one has commented on them, including the Oppenheimer movie crew; but to me they cheapen the feel. My '55 may be the least-expensive 1955 Cadillac, but many folks have commented about the beauty of the cabin.

Thanks for reading!

Michael Chanslor
CLC member number 29829

[Roger Zimmermann]

The parts list say: 1946 to 58: #4633370 Chromium, used with manual door lock in 1958
There is a long list of lock knobs in colored rubber, coordinated with the interior trim.
To solve your problem, if you have access to some machines: turn or take a screw going into the chrome knobs and do a bore and use a tap so the knob can be screwed on the actuator.

[Lexi]

I got a box of spare chromium buttons that I could check/measure for you. Think they all came off of '56s. Clay/Lexi

[Lexi]

Come to think of it, the '56 Series 75's I have seen had colored plastic door buttons but the '56 Series 62s that I have owned all had metal chromium buttons. Clay/Lexi

[MickeyCaddy]

If it's not too much trouble, could you do a quick measurement? It's confusing; the knobs I bought from C-Daddy in Vegas state "Replaces part # 4633370", but the pic I posted shows that they're unusable. The seller kindly refunded my money, but told me "We don't get it - we checked these on our cars here and they fit perfectly."
Thanks in advance.

[Lexi]

If it's not too much trouble, could you do a quick measurement? It's confusing; the knobs I bought from C-Daddy in Vegas state "Replaces part # 4633370", but the pic I posted shows that they're unusable. The seller kindly refunded my money, but told me "We don't get it - we checked these on our cars here and they fit perfectly."
Thanks in advance.

I will pull the box. Records show I should have 22 of them in chrome. They would all be vintage as I pulled them from parts cars myself, and got others from a buddy who did the same. Not reproductions. My '56 Limo has the hard rubber or plastic ones. The chrome ones I have look like the one in your photo that shows it sticking up above the window trim. Hope mine are longer    Is it possible that your threaded pins have changed with those of a longer reach and different diameter? Think I got some door pins and actuator mechanisms. Will pull one of those as well if I can find them, and check the thread pitch and fitment. Might take me a day or two. Clay/Lexi

[dn010]

I apologize to jump in on this thread, but does one know where I might find the little ring that goes in the door for the lock knob to ride down on?

[alzink]

I had the same problem with my 55
Believe it or not I found some black plastic escutions at my local hardware store in those hardware variety boxes. I had to slightly open the OD of the opening then everything fit perfectly

[Lexi]

MickeyCaddy, I have not yet had an opportunity to go to my storage and check for those buttons, but have not forgot. Hope to get there by the weekend. Life has been throwing curves at me lately. Clay/Lexi

[Lexi]

Well after some searching, I did find my Cadillac door lock buttons. Attached are a few images with a scale, that show some of their dimensions. While I did not locate my door pin locking mechanisms, (probably there somewhere), I did not have to hunt for them as one of the buttons has a fragment of the threaded door actuator pin still in it. I unscrewed it and put a thread pitch gage on it. While the threaded rod was corroded a bit, (which expands metal), my pitch gage seemed to read 40. So if the metal did not expand significantly due to the corrosion process, I am assuming this is 40 threads per inch, in National Fine. I put my digital Vernier on the rod just below the threaded portion and it read 0.1305 of an inch in diameter, on the corrosion. So that diameter of metal rod, cut with a 40 NF tap should screw into a button designed for your Cadillac. Also, I noted that the opening hole of these buttons is oversized, but narrows inside where the threaded portion is. Perhaps your buttons from CaddyDaddy were not finished, thus compelling you to tap the inside? Or they have plugs inside them to protect the interior thread which must first be removed prior to use? Or your pins are different as have been changed on your car, (doubtfull). For those interested, I also ran across the "rubber" or "plastic" Series 75 pins. They only have a 0.1305 inch hole as they were designed to accept the pin's thread immediately. Same thread size though, just no larger "starter hole". These 4 pins are available and if you are interested in buying them send me a PM. $35 USD for all 4, shipping to be determined. Clay/Lexi

Note: Have tried several times to post images without success. So posting my text reply first and will try to post the pictures in a new post here in this thread. Was unable to quote MickeyCaddy, which seemed to trigger this.

[Lexi]

If it's not too much trouble, could you do a quick measurement? It's confusing; the knobs I bought from C-Daddy in Vegas state "Replaces part # 4633370", but the pic I posted shows that they're unusable. The seller kindly refunded my money, but told me "We don't get it - we checked these on our cars here and they fit perfectly."
Thanks in advance.

Hello Michael, please see my above post. Clay/Lexi

[Lexi]

If it's not too much trouble, could you do a quick measurement? It's confusing; the knobs I bought from C-Daddy in Vegas state "Replaces part # 4633370", but the pic I posted shows that they're unusable. The seller kindly refunded my money, but told me "We don't get it - we checked these on our cars here and they fit perfectly."
Thanks in advance.

One more try to post images. Clay/Lexi

[Lexi]

If it's not too much trouble, could you do a quick measurement? It's confusing; the knobs I bought from C-Daddy in Vegas state "Replaces part # 4633370", but the pic I posted shows that they're unusable. The seller kindly refunded my money, but told me "We don't get it - we checked these on our cars here and they fit perfectly."
Thanks in advance.

System now working...for now. So here are a couple more images. One shows the button with it's intended pin (fragment). The other shot shows the pin threaded inside the button. Note larger hole opening, but down inside it narrows and is threaded to accept this 40 NF threaded rod. Clay/Lexi

[MickeyCaddy]

Clay/Lexi,
I'm sorry for the late reply. I hadn't logged in to this Forum for a while; when I did, I found I was unable to reply due to the "Not a Member" glitch affecting many of us. The glitch was finally resolved today (whew!)
When I read your posts I was amazed – you completely solved my problem, one that had me and many others vexed for months. You are exactly correct; the chrome lock knobs have a much smaller receptacle/hole way up near the top of the lock button that fits my lock rods perfectly! I had saved one chrome knob, that I'd perceived as non-fitting, just in case someone came up with a solution – and you did! Brilliant! I can't thank you enough!!!

MickeyCaddy
CLC member #29849

[Lexi]

That is great news. Glad that another Caddy mystery was solved. Clay/Lexi