WANTED: Non-potmetal trunnion assembly for Columbia AT

[phonogfp]

Clay,

Thanks for the photos. A picture's worth a thousand words!

The pot metal carriage on the left looks like it may have been re-worked. The sleeve beading on the left looks different from that on the right. I'm wondering if the stabilizer (the part that hangs down and rides the slot in the casting) was re-mounted in a different place. Are there additional holes in the bottom?

George P.

[phonogal]

Clay, I read that the early AT had the raised mandrel and the late AT had the lowered mandrel. Jan

Nope, just the opposite, at least according to Hazelcorn's Columbia Phonograph Companion, Volume I. It is the Type 2 that has the high trunnion, and from the pictures that trunnion's design and construction are very different from either of the ones shown above. Hazelcorn relates that the high trunnion was one of two major improvements made by the Type 2. (The second improvement was the introduction of the #5 reproducer.)

Clay

Clay, Thanks for the information. I just read it wrong. Sorry Jan.

[FloridaClay]

Clay,

Thanks for the photos. A picture's worth a thousand words!

The pot metal carriage on the left looks like it may have been re-worked. The sleeve beading on the left looks different from that on the right. I'm wondering if the stabilizer (the part that hangs down and rides the slot in the casting) was re-mounted in a different place. Are there additional holes in the bottom?

George P.

The potmetal one was repaired (by Jean-Paul) after it deteriorated and came apart in several places, as potmetal is want to do, but does not work very well. As far as the relationship of the various parts, mounting points, etc., there is no indication at all that either has been modified in any way. The potmetal one worked very well until it broke up, by the way. The assemblies are just for 2 different model designs.

There should be good pre-potmetal trunnions out there, as the switch to potmetal for the Type 1 ATs occurred late in its production run and a lot of them were sold. Now just to locate one and give the original a decent burial in my parts stash.

Clay

[FloridaClay]

I have done a bit of YouTube sleuthing to view a playing Type A and a playing Type AT. The potmetal one is the correct design for my AT Type 1. However, the trunnion on the A appears much closer to the design for the AT than the one I have that was represented as being for an A--so you might be right about that George.

Type A http://www.youtube.com/watch?v=6byy4OfakX8

Type AT http://www.youtube.com/watch?v=2IfyNkQNMXI

This leave me wondering what model my plated brass trunnion was really made for. It would operate with the connection for the horn riding straight up on top and the connection for the reproducer riding quite low. I am thinking that it is really for one of the machines that had the feed tube riding ABOVE the mandrel, like a Type U with an Amet motor or one of the various electrics with the horn being behind the reproducer rather than in front (of course with the trunnion reversed on the feed tube from where I have it in the pictures).

Clay

[phonogfp]

Okay Clay - - here'a another possibility. I once had a nickeled brass Type A carriage very much like yours that came on an AO. It clearly had been messed with as evidenced by the defaced screw heads, and it certainly wouldn't work on the AO (see below). I traded it (to Jean-Paul...hmmm...) for the carriage I needed for the AO, but I always wondered if the A carriage had been assembled BACKWARDS.

In other words, would your nickeled brass carriage work if the upper part were removed and its position adjusted 180 degrees on the sleeve? (The lift lever and half-nut would need to be turned 180 degrees as well.) I never had the opportunity to try this on mine before I traded it.

Good luck!

George P.

[FloridaClay]

It can't hurt to try that George, but will likely be a couple of weeks before I can get to it due to holiday activities and some upcoming travel.

Clay

[Lucius1958]

the switch to potmetal for the Type 1 ATs occurred late in its production run and a lot of them were sold.
Clay

Actually, it appears that Columbia went over to potmetal fairly early: I have an AT from about the first year of production, and it had a potmetal trunnion…


Bill

[FloridaClay]

the switch to potmetal for the Type 1 ATs occurred late in its production run and a lot of them were sold.
Clay

Actually, it appears that Columbia went over to potmetal fairly early: I have an AT from about the first year of production, and it had a potmetal trunnion…


Bill

Is yours a Type 1 or a Type 2?

Clay

[Lucius1958]

the switch to potmetal for the Type 1 ATs occurred late in its production run and a lot of them were sold.
Clay

Actually, it appears that Columbia went over to potmetal fairly early: I have an AT from about the first year of production, and it had a potmetal trunnion…


Bill

Is yours a Type 1 or a Type 2?

Clay

It's a Type 1, serial # 214331; it has an early style #2 reproducer on it, and a 'Broadway' decal.

Incidentally, I remember seeing an AT on Tim Fabrizio's site a few years ago that had an (original?) brass carriage; its serial # was 210614 - so it seems the switch was made sometime shortly afterward.

Bill

[FloridaClay]

Incidentally, I remember seeing an AT on Tim Fabrizio's site a few years ago that had an (original?) brass carriage; its serial # was 210614 - so it seems the switch was made sometime shortly afterward.

Bill

I have not found anything detailed. Hazelcorn's Columbia Phonograph Companion, Volume 1, states that: "It should be noted that late in the production run of the first style 'AT', Columbia switched to pot metal for both the chassis and carriage sleeve assembly."

Clay