Beseler 45 Counterbalance Spring

[Sundowner]

So someone was throwing away two reasonably-intact Beseler 45's...one is an MXII and the other is an MXT. Neither is in great shape, but I can salvage and swap enough parts off of one or the other to get myself one really nice working unit. The only issue that I've found that's going to be a bit of a pain is the fact that at some point in time a previous owner (or moronic college student...as these originally came from a college darkroom) has removed the counterbalance spring retaining screw in the lower cross tube. Is there a simple way to access the interior of that lower tube and put the spring back in place? I know how to set the tension on the spring once it's in - at least, according to the manual - but there's nothing about actually re-seating the spring itself. How the screw got removed, I'll never know...it's the ONE piece that the manual says to never touch. Just my luck that someone monkeyed with it. Any help is much appreciated.

Note: I can probably swap the other carriage/cross tubes into place into the frame that I'm using, but the nicer of the carriages is the one that has the missing screw. That's a last resort, and since the enlargers are being taken completely apart I'm not averse to digging inside of one.

 

[Sundowner]

Any thoughts, anyone? Someone here has to know how to do this...

 

[ic-racer]

I don't see how one would put that screw back in place without taking the whole tube out of the enlarger frame. I suspect it would not be to difficult as you should be able to re-insert the screw with no tension on the spring, then wind up the spring once the cross tube is installed on the enlarger. I don't have this enlarger, just the parts diagram, so I may be wrong.

 

[Leigh B]

Total speculation here, as I've never had one of these apart...

The spring is most likely a large coil spring.
The long hollow tube and the screw location argue strongly for a coil spring rather than a leaf spring, which is the other option.

In such an application, the spring must be stretched along the tube in its relaxed state, because as it's wound/tensioned,
the effect is to add more turns between the end points, and empty space must exist for those turns to occupy.

To accomplish this would require a special fixture/jig to hold the parts in place, to facilitate insertion of the screw.
I suspect a nut or threaded hub is used with the screw, and probably held in place by the same fixture.

The admonition in the manual to leave the screw alone supports the assumption that they used an assembly fixture.

- Leigh

 

[Sundowner]

Well, I decided to jump in and figure it out.

The answer is this: you take the entire carriage apart...and that includes removing the roll pins that retain the drive gears. Once you're in that far, the coil spring is easy to access...and since it's not under a great deal of tension at rest I don't think that an assembly jig is used to install it. However, if you don't have a vise and some roll pin punches you're going to be in for a hell of a fun time; I had them and it was simple. I even found the retaining nut for the screw buried in some grease inside of the spring.

A word to anyone with one of these enlargers: check the gearbox if you ever have to take the thing apart...mine only contained the desiccated remains of gear oil. I cleaned out the sludge and added a bit of 75w-140 and the worm drive immediately acted a lot happier.

Now I can work on an LED head.