Loose canon pinion--how to fix?

[jboger]

I have an early 20th C time-only banjo movement that seems to have a loose canon pinion . I call it that because that's what a watchmaker would call the equivalent part in a pocketwatch. Not sure if it's the same term when applied to a clock.

This "canon pinion" is just a brass tube that fits over the long center wheel arbor. What's the least invasive repair I can do to remedy this?

 

[bruce linde]

if only there was a way you could post photos so people could see how your movement is constructed, and offer informed comments.... oh, wait... there IS a way.

seriously, i want to help, and i’ve been working on a couple of banjo clock movements just this week... but can’t see what you’re seeing.

the remedy starts w posting large clear well-lit photos... pls

 

[jboger]

Well, a picture says a thousand words. If it were a watch, I might mount the canon pinion on a stump and give the right stake a tap to put a dimple in the side of the canon pinion. I hope to avoid that, if possible. If slipping a few fibers of cotton between the center wheel arbor and the canon pinion would work--and people think that's a legitimate repair--I might consider that. But here is a photo of the disassembled movement. If You would like a close-up, I can get my camera out and take more.

John

 

[bruce linde]

if you're talking about the minute hand cannon (with the square edges at the very top where the minute hand gets fastened) in the upper right of your photo, that slips over the arbor... but not before the little three-legged tension washer two below it. typically those tension washers sit on a little edge of the arbor... just above the front plate. when you slip the minute hand cannon onto the arbor and pin the minute hand in place, the tapered pin should push minute hand + cannon down onto the three-legged tension washer with enough pressure to hold everything to the arbor as it turns, but still let you move the minute hand to adjust the time.

is that not working for this movement?

the general rule of thumb is: if the cannon has slots down the sides, it's meant to crimp onto the arbor... and you can crimp a bit if needed (i try to find a piece of rod a tad narrower than the arbor and then crimp down with that running through the cannon so i don't crimp too much). if there are not slots, look for a tension washer.

does that help?

 

[jboger]

Bruce:

You have very accurately described the situation. I just got the clock. I took the movement apart and cleaned it. But I never fully reassembled the clock, that is, I did not repin the minute hand on. The hour hand is a friction fit. I placed that on yesterday and set the pendulum in motion. The clock runs well,. It ran throughout the entire night, but the hour hand moved only a couple of hours--far less than it should have.

I'm cleaning up the case right now. Need to do that before I re-assemble everything. When I do, I will re-pin the minute hand on. Let's hope that solves the problem, that is, if there is a problem.

Many thanks.

John

 

[bruce linde]

John

When you pin the minute hand in place it pushes the minute cannon down so that it turns with the arbor. But it also pushes the gear at the bottom of the minute cannon down enough to engage with the motion works that drive the hour hand cannon. I’m wondering if you might need to adjust that tension washer slightly and make sure that when you pin the minute hand and place the motion works are engaging properly. I would get it all back together put the hands on it and then look at it from the side as I turn the minute hand manually, and watch as the hands go around properly. If they do it like that, they’ll do it once you put the movement back in the case. Make sense?

 

[jboger]

Bruce:

I finished putting the clock back together today. Once I pinned the hands back on, the hands moved properly. It's ticking away now and keeping time. Thanks for your insight.

John

 

[bruce linde]

how about some photos of the patient post-op?

 

[jboger]

Here you go.

After I got the clock, i discovered it did not run. This was due to the pendulum rod rubbing against the weight. If I pushed the weight away from the rod, the clock ran well. I thought the weight was put in backwards, and so I switched it around. The rod seemed to be free and the clock ran for a few hours--then stopped again. I again pushed the weight away from the rod but the clock still would not run--some other problem now.

This time I removed the movement from the case and inspected how the cable was wound about the winding arbor. It was snagged in such a way that the cable would not unwind. After a good clean, a reassembly, and an oiling, with the cable wound correctly about the arbor, all seemed well until I placed the hour but not the minute hand back on (I wanted to make sure the clock ran before I finished assembly).

As we now know, the minute canon was slipping because the minute hand was not pinned on. It's pinned on now and the clock runs quite well. I'm adjusting the length of the pendum to bring it into proper time.

As for the case, it needed only minor work. Some screw holes had been enlarged and there were too many mismatched screws to my liking. Also one of the glue blocks fell off. I plan to use some gilders paste to touch up the gilding, which is in not too bad shape. Only thing is, I can find my gilders paste.

The clock is by Killam of Pawtucket, RI, ca. 1910.

Thanks again for the help.

 

[bruce linde]

nice.... congrats

 

[kinsler33]

A good many anniversary clocks have this same arrangement.

Mark Kinsler