Repairing...taking apart Columbia Tonearm

[Steve E.]

A kind man, probably now on this board, sold me a "new" (ancient but good) piece last year or so, to fit to this Columbia tonearm (top right picture). You can see how the one on our right in each picture is cracked so that it can't be screwed on, and can't hold up the tonearm.

All well and good, except that the tonearm does not fit well into the top of the new piece. It won't snap in, and it falls out. It appears there is a little warpage. It snaps into the old piece just fine.

Also there is an important difference at that joint. If you look at the two pictures on the left, the "new" piece has some sort of extra metal tab which seems to impact the tonearm's ability to descend.

So I would love to use the base of the new piece and the elbow of the old piece. Can anyone suggest how I might disassemble these pieces? There is a big threaded washer on the bottom of each and I have no idea how to unscrew it without causing damage. thanks!

[Covah]

As far as I know there are three ways to attach the tonearm to the elbow- simple twist on, identified with a round spring plate held on by two screws; a push-on system with a compression ring; and a later push-on version which is larger and comes with the autostop, as shown. The earlier tonearm will be loose in the elbow, as described.

Making these match is a challenge. I've had two $50 elbows in my parts box for years waiting for a matching tonearm. They are the ones with the compression ring which fits into a groove.

[Brad]

Steve E,

I believe that what you want to do is use your original tone arm and elbow with just the bottom piece of the new base

I thought I had one of these in my parts bin, but I could not find it. I did restore a machine with this type of tone arm many years ago so what follows is based on very hazy foggy, and all around unreliable memory.

The sickle shaped shut off arm is attached to the elbow. I seem to recall that there is a compression ring that sits in grove around the elbow piece that holds the shut off arm on and holds the elbow piece into the base. This ring should be split (have a cut in it) You need to get a small screw driver under one end next to the split and work it out of the grove and off the elbow.

If that is not correct, then look for a screw in the side of the base piece which provides a stop for the tone arm travel and holds the elbow in. This is the method on most Columbia non-shut-off tone arms.

Hopefully my memory is right (or at least in the ball park).

[Steve E.]

I believe that what you want to do is use your original tone arm and elbow with just the bottom piece of the new base

That is correct!

I will try out your idea and see if it works. Thanks much!

Steve

[Steve E.]

There is indeed a screw in the side.

My immediate concern is the threaded washer in the base. This holds the elbow onto the base, and compresses a spring. I don't know how to get the darn washer off.

[Brad]

The screw acts as a travel limit stop. I will have to be removed to remove the elbow.

That threaded washer also needs to come off. I can't see by your pictures if the edge is knurled, or if there are slots of holes for a pin spanner. If there are slots or holes, that would be for a tool.

Can you get a better close up? Do they look different on each base?

[Covah]

Welcome to the world of Columbia!

If you can get this system to work it's really something. It's a fully automatic stop. If you put the tonearm down and walk away the turntable will shut itself off. It will shut off at the end of a record without adjustment. Even the highest end Victrola never had that, not until the orthophonic era.

The washer in the base is designed to slide up and down to adjust pressure on the hook, which transfers tension from the record to the brake. Too little tension and the thing will stop while the record is playing. Too much and the tonearm will be stiff.

[Steve E.]

The washers are the same, and they do seem to be designed for a tool. They each have square-ish holes or indentations at 9:00 (small), 12:00 (big) and 3:00 (small). The problem is....I do not have such a tool and it seems needed for the torque. I already cracked off a small (probably non-fatal) piece of the base while trying to remove the thing.

Any ideas on fashioning a new tool?

[Brad]

Steve,

You might be able to fashion a tool by taking a piece of steel, or flat metal and cutting a "u" shape out to fit over the elbow. The remaining metal will fit into two of the slots. I am not a metalurgist so I don't know how to specify what metal to use, but you will need something much harder than sheet metal. One idea would be to fashion it from a putty knife with a appropriate width blade.

Good luck.

[Brad]

Steve.

Any Luck???