Stuck Cannon Pinion

[Bentrider]

As per title, this beast is well stuck. No response to gentle prising with a screwdriver and I'm reluctant to exert too much pressure. I've sprayed it with WD40 and left it to soak for a while. I found a suggestion of a trim removal tool but does the panel have any better ideas?

 

[roughbarked]

These need the main shaft to be tapped through the plate with a light brass hammer. You'll need an anvil under the plate of a type that doesn't interfere with the centrewheel.

 

[Dr. Jon]

Possibly the canon pinion is screwed in place. Before hammering try to unscrew it. Assume it has a right hand thread (Righty tighty lefty loosey) but if it does not come loose that way try it the other way.

I have a repeater set up this way, with a right hand thread.

 

[roughbarked]

I haven't seen a screw on one but that's always worth checking.

 

[wow]

Why are you removing it? If that hole doesn’t need bushing, I would leave it. Just clean it well.

 

[Bentrider]

Why are you removing it? If that hole doesn’t need bushing, I would leave it. Just clean it well.

I've just noticed something odd. For all it's solidly fixed it still rotates easily around the centre wheel arbor and looking into the movement as I hold everything else fixed and turn the cannon pinion, the entire centre wheel arbor is turning up to the wheel itself. I think I will have to leave it in place until I get everything else dismantled and see what is going on.

 

[roughbarked]

Yes. Unless the hole is badly worn then it is best to leave it alone. Yes the canon tension is usually between the wheel and the shaft. The star lifting wheel is simply tightly attached.

 

[Willie X]

Heat ... about 4 seconds with the ole Burnz-O-Matic, small flame about one inch long. Direct the flame to the brass part and be set up to immediately apply force.

If you can get a helper, it's better to put the heat to it while the force is being applied.

Willie X

 

[dickstorer]

Do as Willie says. I, unlike others always remove it. Support the entire plate on a crows foot, apply the heat and tap the center arbor. A wood mallet is good for this. Direct the heat to the brass, it expands quicker than the steel.

 

[TEACLOCKS]

This will work if you can figure out how it works.

 

[Bentrider]

I got round to dismantling the movement today and the centre wheel is somewhat unusual. That cannon pinion/cam is rigidly fixed to the centre wheel arbor and is as unmoving as ever. On the other sided there is a similarly fixed sleeve on most of the length of the arbor. The centre wheel itself rotates freely on the arbor but is held against the sleeve by a spring washer giving the necessary friction to turn the hands. I assume the cam and sleeve are (very tight) friction fit but I'm really not minded to try and remove them, I'll just clean them in situ.

 

[R. Croswell]

That’s like taking a shower with your shorts on, but it seems to be common practice when the pivot hole isn’t badly worn. These things can put up a fight but will eventually give up. Warm the part and add penetrating oil such as Kroil or liquid wrench and let it work 24 hours, periodically adding more. Have ready tools to pry equally under both sides, the get the part HOT with a small butane torch. Don’t get it red hot but don’t be afraid to get it hot enough for the oil to start smoking. Then pry it off. It should come right off.

An alternate method requires making a brass driver to slip over the shaft. In a brass rod, drill a deep hole that’s a bit larger than the threaded part of the shaft, then drill out part of the hole so it slips over the shaft (make sure the threaded part does not bottom in the hole). Support the plate with a crow’s foot or split stake close to the arbor, heat the part, use the brass driver and small hammer to tap the shaft through the pinion.

Once you remove the star wheel, you will never get it back on in exactly the same place, so youwill need to adjust the collet in the minute hand so it strikes at 12, which is another reason some prefer to leave it alone.

RC