Brunsviga 13 ZK frozen stuck carriage

[Damien B]

Hello,

I am the lucky owner of a Brunsviga 13 ZK, probably made in the 1930s by the low serial number. It was rusty, very dirty, and stuck when I got it.

After opening it and cleaning it the best I could, I was able to free the stuck digits on the input, but the carriage remains frozen stuck and won't move the slightest.

I made sure the security screw underneath is unscrewed (it doesn't seem to do anything), dozed the carriage and its rails with WD40, let it sit for a day, but even pushing the carriage lever while *gently* taping on the carriage side with a hammer, no movement is perceptible.

The crank can move a little but also seems to be stuck by some cogs or pins, probably from the carriage since the only stuck lever is the one that resets it. I also noticed I can shift some pin wheels manually on the carriage, but about half of them can move a little but not to the next or previous digit.

I tried to remove the carriage to check what is going on, but the four screws holding it to the base are out of reach since I can't shift it.

I am out of idea for what to do next, maybe someone more knowledgeable than me could give me a hint?

Best regards,
Damien

[John Scriven]

Hi Damien,

I have a 13ZK. The carriage is connected to the position marker on the rev counter via a linkage. Moving the carriage one way moves the position marker (which indicates which digit on the rev counter is active) the other. There is a cylindrical rod running from side to side at the rear of the calculator on which the position marker runs. The position marker may need to be freed off. You'll need to remove the back plate for access. My 13ZK was fine when I got it, but I did need to do this on one of my other Brunsvigas.

I'll be away from my machines for a few days, but if I need to have a "hands on" look I'll be able to get back to you if necessary

Best Wishes

John

[Damien Boureille]

Hi John,

Thank you for bringing this to my attention. I can slightly move the position marker along the rod with a screwdriver, so it doesn't appear to be stuck. It's connected to the carriage through a large lever that can be rocked lightly up and down on its stand, so the lever doesn't appear to be stuck either. However, the opposite end on the carriage side doesn't move at all, just like the carriage itself. It feels like it's fused to the base of the calculator.

The accumulator reset lever is also stuck but can move slightly with some resistance. Similarly, the crank won't turn, it moves slightly but seems obstructed by something (obviously I pull the knob before trying to turn it).

The input wheels, the counter and input reset levers work, and the crank rod activates the lever on the left side when pulled. I suspect it all comes from the carriage.

I've attached two pictures for reference, one from the back with the position marker visible (though there's not much to see, I'm afraid), and another of the front, showing the digits I managed to free and reset manually to zero.

Hopefully I won't have to disassemble everything...

Best regards,

Damien

 

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[Damien Boureille]

Some progress. I could free the crank and the carriage rotor, so the calculator now works well saved for the stuck carriage. This is already a relief as it's no longer a boat anchor.

Long story short, upon close inspection, I realized that the pins on the crank wheels were hitting those of the carriage on their lateral extremity. Also, the rod that gets pulled with the crank was barely moving. Gently moving the carriage with a hammer by a fraction of a millimeter freed everything up.

Now the carriage still feels fused to the calculator, it took a lot of gentle hammering to move it ever so slightly. The carriage lever can be moved left, right and frontward and I can see some mechanisms being triggered when I move it, but the carriage doesn't move. I could inspect the safety screw and it appears to be fully retracted, so the problem seems to be elsewhere, I'm still out of idea where.

Damien

On 8 Sep 2023, at 22:44, John Scriven <john.s...@outlook.com> wrote:

[Damien Boureille]

After a lot of WD-40 spraying, brushing the rails with acetone, and not-gentle-anymore hammering, the carriage finally started moving a little, then more and more. Meanwhile I sprayed the rails with generous amounts of WD-40 which removed a lot of rusty black goo. Now the carriage is free and glides effortlessly.

My last worry is the first two digits of the carriage that sometimes get stuck when subtracting, requiring me to pull the crank upward a little while it's still partially disassembled, but maybe the carriage wheels just needs more cleaning and lubrication.

Case closed, now off to repainting this beauty. Thanks again John for your tips.

Damien

On 8 Sep 2023, at 22:44, John Scriven <john.s...@outlook.com> wrote: