MSR T56 - hands not moving advice please

[WatchMaker]

Hi

I've got an MSR T56 I've just serviced but where the hour and minute hands rotate okay if adjusting the time ... but hardly move at all under normal operation (although the watch ticks along fine).

This sounds like a classic cannon pinion issue I thought ... but because I don't have a proper cannon pinion tightening tool and happened to have a 'spare' MSR T43 movement (where the hands do turn under normal operation) I thought I'd play it safe initially and just swap out the cannon pinion from the T43 to resolve the problem on the T56. Imagine my disappointment when hands are still not moving. :-(

So I need some advice please! This MSR T series is a bit strange in that the cannon pinion sits off to the side. Looking at the movement's part sheet this is part 207/1 described as "barrel-driven minute pinion with additional cannon pinion".

I could try tightening the (original) cannon pinion but this wouldn't explain why with the swap-out the hands still didn't move. Any other ideas?

If the advice is to persevere with the cannon pinion how would I go about tightening? I know usual advice is "it's a friction fit so not too tight" but without a proper tool how do I judge this?! Also the two part pinion's shaft appears solid rather than hollow. I'm worried about damaging a part that's not listed on Cousins etc.

Many thanks.

[rogart63]

Same problem as this maybe? http://forums.watchuseek.com/f6/cerberus-revue-t56-problem-1015174.html. 

Not easy to tighten that kind if pinion. I have used an oiler and a nailclipper. Maybe easier to find revue 56 parts? 

[clockboy]

it still looks like a canon pinion issue checkout "rogart63's post"

[WatchMaker]

Many thanks.

I had actually found that article in my own research but it didn't help me in two fundamental ways: i) why would the same part working absolutely fine in the same calibre/series of movement not work when simply swapped in? and ii) if there are no other explanations and the consensus is it has to be the cannon pinion then how do you experts know what is "'enough tightening"*.

* I've read lots of advice on cannon pinions and I suppose if I were to summarise, these all say something along the lines of "it's a friction fit so don't overtighten". 

I've taken the plunge and separated this particular cannon pinion as per the picture. If point i) is a bit of a mystery and it's unlikely to be anything else then can anyone offer me advice on point ii) please? I can confirm that the axle in this case is solid.

Thanks.

 

[rogart63]

That is strange. Have you checked that everything moves if you turn the barrel by hand. Take of the balance and pallet fork. And see if the drivetrain moves like it should. Cannon pinion tightening is very tricky as it can be to tight.

[WatchMaker]

The movement will run quite happily with the balance still merrily swinging away this morning.

When I got the movement it had the hands problem but I thought a service and the 'swap-in' would suffice. I'm happy (!) to disassemble the movement again but I always assemble the drivetrain without the balance and fork and ensure it moves freely. I'll recheck everything just in case the mystery can be explained by something other than the cannon pinion!

[oldhippy]

This is very bad here. I dread to think what it’s like on the inside of the other part. You need to replace it with a new one.

[WatchMaker]

Just an update on this ... as I know it can be annoying if advice is given but the outcome is never known!

Although the cannon pinion was the main suspect there was still the nagging doubt for me that I'd replaced the movement's original with the same pinion from a working watch. I therefore first put very small markers on drivetrain wheels to check that everything was turning correctly in the movement itself ... which it was.

I then used the replacement 'working' pinion and with a pair of fine cutters applied pressure to ensure a tighter friction fit. After refitting I could observe the hands moving ... what a relief. My theory is that the pinion working in the basic manual wind model, failed to work when moved to the automatic-with-date model as there is the extra wheel to move for the date change mechanism. The friction must have been on the cusp of tolerance and when put in a movement with extra 'drag' this was enough to overcome the friction and cause the pinion's action to fail.

I then had a hair pulling moment because whilst the hour hand was sweeping accurately the minute hand wasn't. Aghhh! Turns out the minute hand was slightly loose and I had to go about closing up the hole ... but that's another story.