Metamec Electric Clock stalling - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Mike Phelan · 11th Dec 2014, 4:03 pm

Hi Mark,
Good point. I tend to use a broach* (or several broaches) rather than a drill; same for the pivot hole in the new bush.
Either way, it's necessary to keep to the position of the original hole by "leaning" on the side away from the oval; once you've got it round just drill or broach as normal.

* A clockmaker's broach is a five-sided tapered steel thing only to be used on soft metals like brass. Available from M&P or similar.

mark_in_manc · 11th Dec 2014, 5:38 pm

Hey, that's great - I've learnt of a new tool!

cheers
Mark

andrewn · 11th Dec 2014, 8:51 pm

Interesting to read about Mark's repair of the movement. Mine was worn out in exactly the same way. I tried twisting the bracket with the oval hole to try and prevent the worm gear moving away. It worked to some extent but whilst working on the movement I had trouble with rotor jittering back and forth rather than spinning properly so that's when I gave up with it. My sweep quartz movement has become unreliable and keeps stopping so I might have another go at repairing the Metamec movement. I nearly threw it away the other day but luckily it's still on my workbench.
Regards, Andrew.

mark_in_manc · 12th Dec 2014, 9:43 pm

Andrew

I'm with Mike that mine is not a very 'proper' repair...but it works and should last a long time. Next time I think I might make a bush on the lathe - but the advantage of my method here is that you don't need any special tools to do it. You could dispense with the 10BA fastener, and solder (or...horror...perhaps even glue) the new piece alongside the tab, making it even more in-scope for most folks on the forum.

My rotor jittered if there was too much load on it (keeps stalling and re-starting). You may have messed up the shaft alignment a little by twisting the tabs, but you can perhaps get this back with a little more messing about.

Perhaps it is not surprising that this bearing fails on a synchronous movement - it's running way faster than anything found in a clockwork setup. The only thing running faster here is the motor shaft, but Metamec get round this by having it floating and centring itself using a spring at one end, and presumably the magnetic forces in-play as the thing is excited by the coil current.

All good fun. Don't bin your movement - I'd have a go at it if you get fed up.

cheers
Mark

SteveSmit · 15th Dec 2014, 6:14 pm

This is an excellent suggestion this ovality. I never even thought to look for that. I'll check and get back to you, I'm not at the same place the clock is at the moment. I will update!

Cheers,
Steve.

SteveSmit · 17th Dec 2014, 8:46 pm

Looks like the idea of the brass holes being worn was spot on. I had a bit of a poke at the worm gear with a toothpick and it was astonishing how far I could move it.

I'd missed it mainly because I'd just assumed that it was the nylon gear that was the problem. Totally overlooked that the steel worm might be misaligned. Oh well, chalk that one up to experience.

As for fixing it, I might look into the broach method in a little more detail. Any other tips for an utter beginner like myself?

Thanks again everyone for the pointers on this. It miht seem a bit over the top for an old utterly standard clock like this one but I enjoy the process I must admit!

andrewn · 18th Jan 2015, 6:41 pm

I did a repair similar to that shown before by gluing a nut in place to remove some of the slack. I find that the movement might run for a minute or so but then stop so there obviously something else that isn't running very well.
Could someone confirm whether the brass washer that's on the centre shaft is fitted in the correct place? It fell out when I dismantled the movement.
Thanks for your help. Andrew.

Mike Phelan · 19th Jan 2015, 10:05 am

Has the centre arbor any end-float when it's assembled, Andrew?

andrewn · 24th Jan 2015, 1:39 pm

Hello Mike, yes there is some end-float. On looking further I think the washer goes the other side of the gear. There is a mark visible on the copper spring which I think was caused by the washer. On re-assembling the clock seems to running quite well so it might be fixed. Regards Andrew.

Mike Phelan · 24th Jan 2015, 8:27 pm

Good stuff, Andrew, think yu've sorted it.

mark_in_manc · 26th Jan 2015, 11:34 pm

Hi Andrew -

On mine, the oval bearing at the worm-end of the shaft (the other end from that at which you glued your nut) was the one which was causing the loss of motion - did you repair this end too? Might be worth a look on yours - but then again perhaps not if it works!

cheers

Mark

andrewn · 27th Jan 2015, 9:00 pm

Hi Mark, no I didn't repair the other end because it appears the worm gear is making good contact. I had previously bent the worm gear brackets to try and improve the contact between the gears and although I have straightened them again it's not exactly as it was. One problem I found is the anti-reverse clip has a tendency to jam the rotor so I will probably leave it out. If the clock starts in reverse I can just switch off/on again.
I've yet to run the clock long enough to confirm its ok. It's still on the bench so I really need to get it installed in the clock face and test it properly.

11th Dec 2014, 4:03 pm	#21
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: Metamec Electric Clock stalling Hi Mark, Good point. I tend to use a broach* (or several broaches) rather than a drill; same for the pivot hole in the new bush. Either way, it's necessary to keep to the position of the original hole by "leaning" on the side away from the oval; once you've got it round just drill or broach as normal. * A clockmaker's broach is a five-sided tapered steel thing only to be used on soft metals like brass. Available from M&P or similar. __________________ Mike.

11th Dec 2014, 5:38 pm	#22
mark_in_manc Octode Join Date: Nov 2011 Location: Manchester, UK. Posts: 1,874	Re: Metamec Electric Clock stalling Hey, that's great - I've learnt of a new tool! cheers Mark

11th Dec 2014, 8:51 pm	#23
andrewn Pentode Join Date: Aug 2008 Location: Taunton, Somerset, UK. Posts: 135	Re: Metamec Electric Clock stalling Interesting to read about Mark's repair of the movement. Mine was worn out in exactly the same way. I tried twisting the bracket with the oval hole to try and prevent the worm gear moving away. It worked to some extent but whilst working on the movement I had trouble with rotor jittering back and forth rather than spinning properly so that's when I gave up with it. My sweep quartz movement has become unreliable and keeps stopping so I might have another go at repairing the Metamec movement. I nearly threw it away the other day but luckily it's still on my workbench. Regards, Andrew.

12th Dec 2014, 9:43 pm	#24
mark_in_manc Octode Join Date: Nov 2011 Location: Manchester, UK. Posts: 1,874	Re: Metamec Electric Clock stalling Andrew I'm with Mike that mine is not a very 'proper' repair...but it works and should last a long time. Next time I think I might make a bush on the lathe - but the advantage of my method here is that you don't need any special tools to do it. You could dispense with the 10BA fastener, and solder (or...horror...perhaps even glue) the new piece alongside the tab, making it even more in-scope for most folks on the forum. My rotor jittered if there was too much load on it (keeps stalling and re-starting). You may have messed up the shaft alignment a little by twisting the tabs, but you can perhaps get this back with a little more messing about. Perhaps it is not surprising that this bearing fails on a synchronous movement - it's running way faster than anything found in a clockwork setup. The only thing running faster here is the motor shaft, but Metamec get round this by having it floating and centring itself using a spring at one end, and presumably the magnetic forces in-play as the thing is excited by the coil current. All good fun. Don't bin your movement - I'd have a go at it if you get fed up. cheers Mark

15th Dec 2014, 6:14 pm	#25
SteveSmit Retired Dormant Member Join Date: Mar 2011 Location: Derby, Derbyshire, UK. Posts: 48	Re: Metamec Electric Clock stalling This is an excellent suggestion this ovality. I never even thought to look for that. I'll check and get back to you, I'm not at the same place the clock is at the moment. I will update! Cheers, Steve.

17th Dec 2014, 8:46 pm	#26
SteveSmit Retired Dormant Member Join Date: Mar 2011 Location: Derby, Derbyshire, UK. Posts: 48	Re: Metamec Electric Clock stalling Looks like the idea of the brass holes being worn was spot on. I had a bit of a poke at the worm gear with a toothpick and it was astonishing how far I could move it. I'd missed it mainly because I'd just assumed that it was the nylon gear that was the problem. Totally overlooked that the steel worm might be misaligned. Oh well, chalk that one up to experience. As for fixing it, I might look into the broach method in a little more detail. Any other tips for an utter beginner like myself? Thanks again everyone for the pointers on this. It miht seem a bit over the top for an old utterly standard clock like this one but I enjoy the process I must admit!

18th Jan 2015, 6:41 pm	#27
andrewn Pentode Join Date: Aug 2008 Location: Taunton, Somerset, UK. Posts: 135	Re: Metamec Electric Clock stalling I did a repair similar to that shown before by gluing a nut in place to remove some of the slack. I find that the movement might run for a minute or so but then stop so there obviously something else that isn't running very well. Could someone confirm whether the brass washer that's on the centre shaft is fitted in the correct place? It fell out when I dismantled the movement. Thanks for your help. Andrew. Attached Thumbnails

19th Jan 2015, 10:05 am	#28
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: Metamec Electric Clock stalling Has the centre arbor any end-float when it's assembled, Andrew? __________________ Mike.

24th Jan 2015, 1:39 pm	#29
andrewn Pentode Join Date: Aug 2008 Location: Taunton, Somerset, UK. Posts: 135	Re: Metamec Electric Clock stalling Hello Mike, yes there is some end-float. On looking further I think the washer goes the other side of the gear. There is a mark visible on the copper spring which I think was caused by the washer. On re-assembling the clock seems to running quite well so it might be fixed. Regards Andrew.

24th Jan 2015, 8:27 pm	#30
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: Metamec Electric Clock stalling Good stuff, Andrew, think yu've sorted it. __________________ Mike.

26th Jan 2015, 11:34 pm	#31
mark_in_manc Octode Join Date: Nov 2011 Location: Manchester, UK. Posts: 1,874	Re: Metamec Electric Clock stalling Hi Andrew - On mine, the oval bearing at the worm-end of the shaft (the other end from that at which you glued your nut) was the one which was causing the loss of motion - did you repair this end too? Might be worth a look on yours - but then again perhaps not if it works! cheers Mark

27th Jan 2015, 9:00 pm	#32
andrewn Pentode Join Date: Aug 2008 Location: Taunton, Somerset, UK. Posts: 135	Re: Metamec Electric Clock stalling Hi Mark, no I didn't repair the other end because it appears the worm gear is making good contact. I had previously bent the worm gear brackets to try and improve the contact between the gears and although I have straightened them again it's not exactly as it was. One problem I found is the anti-reverse clip has a tendency to jam the rotor so I will probably leave it out. If the clock starts in reverse I can just switch off/on again. I've yet to run the clock long enough to confirm its ok. It's still on the bench so I really need to get it installed in the clock face and test it properly.