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Minimalist bushing and polishing tool set

murphyfields

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Jun 24, 2020
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I am very interested in any educational materials you might have, so pics of your plywood model are most welcome.

In your approach, I can imagine a case where things are best between mobiles 1 and 2 when 2 is in one position, but best between 2 and 3 when 2 is in another position. Do you have methods for dealing with these secondary effects
 

howtorepairpendulumclocks

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Dec 18, 2020
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Yes, wheels in the train as opposed to at the end are planted (positioned) and the intersection of two arcs struck from neighbouring mobiles. This is why clock trains are rarely in a straight line (there are exceptions). If there were in a straight line, changing the depthing would be tricky/impossible for the knock-on reason you outline. Because however trains are 'staggered', and, wheels and pinions are often at opposite ends of the arbor, life is relatively straightforward. Say you were to re-depth a pinion by 0.5mm on a tall case clock, movement of the wheel at the 'other end' of the arbor would be a tiny fraction of that in terms of change of depthing. I think that is why wheels and pinions are typically arranged this way. In the days of hand made clocks, that flexibility is very useful. In posher clocks like astronomical regulators (and some less posh clocks), the wheel is riveted to the pinion head and moving one will move the other. The biggest challenge is where a hole in a dial etc must be respected and say, a mobile or gear has been replaced with one that in an ideal world, might be a different pitch circle diameter. Of course, if you have access to wheel cutting equipment, making new components is possible and, as always, the professional practice or what some people might call "ethical" issues kick-in and the whole thing goes full circle... thanks for asking the questions. I've enjoyed thinking it through.
 

murphyfields

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Jun 24, 2020
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Just curious, what is your background? Few people would go to the effort of making a plywood model as a demonstration. Hats off to you for helping clock education.
 

howtorepairpendulumclocks

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I'm from the museums and heritage world here in the UK. I've been involved in education in historic craft practice, making, self-employment as a conservator as well as retail, writing... all sorts. My grandfather was an indentured watchmaker and worked for the instrument and clock maker Cooke, Troughton and Simms so I have a vested longer-term interest. When I started 35 years ago, it was difficult getting 'objective' advice (no names!!!) so part of me is paying back for the highly skilled and respected people who have helped me along the way, and part of me is making living from this but I know there is no selling or promotion here which is fine. if I can chip-in, it costs me only a bit of time and I believe (without sounding too conceited I hope), that what goes around comes around. I learn loads from these conversations.
 

murphyfields

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Jun 24, 2020
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As I have been reading a asking on this forum, I have heard about good bushing jobs and bad bushing jobs, how cleaning and lubricating can help but usually wont solve serious problems, hand bushing is usually inferior to using mills and bushing machines, and it left me wondering how will I know if I have done a good job or not, other than trying and then watching it until it fails? How do I know if the pivot drifted when I put in a bushing, and how much did it hurt things? What good does burnishing really do? How much do you need to polish and can things self-polish over time. I have been thinking about setting something up and seeing how much weight I need to get the chimes or strike to work. Then adding a bushing and trying again. Then trying again. Then using a bearing. But I would love to have better tools than that.

No real question here, just kind of a stream of consciousness.
 

howtorepairpendulumclocks

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A really good point. Without any disrespect to those that give skill, knowledge and time freely, without which the world simply would not turn, those questions, "really?", "why?", "is that right?" etc are valuable tools in progressing. Personally, I love the social function of this space. It has always frustrated me that (at least in the uk), there is very little (with notable exceptions) in the way of peer-reviewed research in clocks. There is some and certainly plenty in conservation, but regrettably little that relates to dynamic historic objects, mostly materials science. That is why I would encourage anyone with connections in the academic world to hook-up with universities to explore some of these questions. As you say, home-grown experiments are also of immense value, even if not scientifically rigorous necessarily. I was only thinking earlier today how to rig-up a bushing wear testing machine. It can be done and things like Arduino are really useful in conducting tests. Keep at it and keep asking the questions!
 

murphyfields

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Jun 24, 2020
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I have to say that the people here on these boards are wonderful. Nobody (or almost nobody) gets paid, but they go on here and answer our questions, sometimes the same question they just answered somewhere else, but they all offer their advice and support. And I love that there are the hobbyists and the professionals, the perfectionists and the good enough-ers. We get to choose what advice matches our skill sets and tool sets.

To all of the patient helpers... THANK YOU
 

murphyfields

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Jun 24, 2020
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howtorepairpendulumclocks I have another round of questions for you and your in-situ depthing idea...

Do you use oil in the pivots while you are doing the pairwise checks, or does it matter?

If you go through the checks and decide no bushings are required, but the clock still doesn't work, what is your best next step?

Have you come across many clocks with significant wear but still pass the pairwise depth test?

What kind of correlation have you seen between the pairwise depthing and other common wear tests?
 

howtorepairpendulumclocks

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Dec 18, 2020
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Thanks for the questions; hope this helps.

No oil needed in the pivots while you are doing the pairwise check. I clean (wash) the movement in white spirit/paraffin or a proprietary equivalent anyway so at some level, the bearing surfaces ar ever so slightly 'oily'. I guess if you use water-based cleaning or re-finishing solution and the movement is degreased, yes, maybe a bit of oil on the pivots would not go amiss. without going off at a tangent (PTP), probably what happens is clocks are sometimes chemically etched or re-finished and therefore the brass working surfaces lose their burnished surfaces. Because the clock lacks power or doesn't run, bushing seems like the obvious route. If your clocks are ver squeaking (lifting pieces etc) that should stand as a major warning signal.

As part of checking the depthing, I would have checked for end-shake and side shake already, so hopefully, no problem there. I am highly suspicious of any clock that has been extensively bushed so look at the inside of the pivot holes for 'picking-up' and de-burr with 0000 grade steel wool. Like all clock repairers I look for 'silly' things like pins that are too long, the canon wheel touching on the inside of the hour why bridge if the friction spring isn't compressed enough. Bent pivots, bent teeth. For example when working on a French clock, I always roll the two barrels together. This immediately highlights bent teeth (much more likely on barrels). I am not a massive fan of testing movements on a test stand. I much prefer to completely assemble including dial and hands straight away unless I suspect there will be a problem. Could go on as fault finding quite a process. Happy to expand though if there is a particular area you want me to discuss. Basically, I do like most people do, wash the clock, check the depthing, check the mobiles drop freely from shoulder to shoulder when turning when the frame is inverted. Anything you think might not quite be right investigate and eliminate immediately. It almost never goes away. Anything like a recently replaced mainspring I am extra cautious of. Many times I've seen a new spring that is too strong or fractionally too high and rubs on the inside of the barrel cap robbing power. Sorry, could go on...

Yes re apparent wear. Controversial but pivots moving around in pivot holes, worn pinions and worn looking wheels are only indicators of possible issues. Personally I just shrug my shoulders at ovalised pivot holes unless there is an actual tangible depthing issue. There are exceptions of course and I do get that bushing is a rite of passage and is very much seen as doing a 'proper' job. I am very lucky not to have to respond (much) to peer pressure so it washes over most of the time but I am I admit in an incredibly privileged position.

The important point here (I think and may be wrong) is change. Most folk regard clocks as part of material culture and a record of something. Nobody quite knows what that record means or what we quite do with it but we feel it is important. I would agree with that. With plenty notable mistakes and blunders and irreversible damage I have caused, I try and stick to the there conservation tenets of minimum intervention, reversibility and accountability. At the risk of sounding pompous and/or conceited, these broad guidelines make me ask "really?", "is that right?" and so-on.

I know people are understandably after practical advice, but ultimately it is the thinking and questioning that I feel is important. Inevitably the interventions I carry out today, I will look back on with horror. Things change... which is good.

The only other wear test I have seen is to try the mobiles in a depthing tool. Personally, for the vast majority of clocks, I find testing the mobiles in pairs takes only a minute or two per train. If something doesn't feel right that cannot be explained by re-depthing and bushing, then a closer inspection in the depthing tool is the next step. It would be really useful if there were other way of testing the 'health' of a train. I think I mentioned it already but a Microset timer can be a great diagnostic tool for clocks with anchor recoil escapement because you can use escapement error as an indicator of cyclical amounts of energy at the escape wheel.

Try it.

Hope this helps. Sorry it is a bit of a rant. Hopefully it doesn't send people into a rage. I see loads of bushing without depthing. Remember also the conjectured "original" centre is only an indicator. We cannot ever put the mobile "back" as it once was.

Lots more to say if anyone wants it...

Thanks again for asking...
 

howtorepairpendulumclocks

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P.S. we began to discuss depthing at last week's Open Clock Club. I know adverts are not allowed which I understand and respect so I have to be carful. The Club is free-to-attend and open to all and if you want to watch that session, there is an archive video on You Tube.