Hi

It could be lack of lubrication, worn pivots - or both.
A slight burr, chip on a pivot can quickly elongate a bushing (softer metal).

I would closely inspect the pivots first.

 

Wrong lubricant? Did you polish the pivots?

 

I did lubricate with clock oil. It was not of any brand name product but I would like to think that it was not the issue. I am 99% sure that I did oil every point and with 2 pivots affected it can´t be that I forgot it in both places, I hope.

As for polishing, I don´t have a proper burnisher (couldn´t find any that didn´t cost an arm and a leg). So I made do with one made from a square HSS steel rod (tiny parallel grooves formed in it with a stone). I couldn´t find any good info about making one either. Maybe I should have hardened it? Anyway, it is my opinion that I ended up with a smoother finish than what it was before. It was shinier in any case. But I could be wrong too. And what possibilities there are left other than failed polishing?

 

I would agree. No point replacing worn bushes if you don't check, and if necessary polish the pivots. If the original pivot hole was worn badly enough to need bushing, then the pivot will certainly have been in need of attention.

 

I did check the pivots. They didn´t look at all worn although the pivot holes were. But not to the extent that they are now.

 

Get a burnisher, as in a flat one like a very fine file. Should be about £40 for a decent one.
Get a lollipop stick and sandwich the pivot between the stick and the burnisher using for example your left thumb and forefinger. Then you can spin the wheel by hand using your right hand, whilst using your thumb on top of the lollipop stick to roll it along the burnisher as you turn it, applying a very light pressure. Don't let the pivot spin against the burnisher in one position, you need to keep it moving across the surface of the tool. You are trying to remove any damage whilst keeping the pivot straight. Very important not to get it tapered.
Easier to do than to explain!
I have a Jacot tool, but still use this method if I only have one or two to do. Works well on biggish clock pivots, once you get down to watch sizes you need the proper tools.
You also need a decent loupe so you can see the results.
If you only need to do it occasionally then you could get a piece of flat steel and glue a strip of 2500 grit or finer wet and dry to it in lieu of the burnisher.
Ideally they should be polished afterwards as well.

 

The other consideration is what material bushes did you use, plain brass or bronze?
The brass in some old clocks can be very hard, so if you were bushing a previously unbushed hole your bush may be softer than the plate, although I still wouldn't expect to see wear like that. I would always use bronze if it's a keeper.
Do you have a loupe? Very often you will find something that may look smooth to the naked eye can be like a ploughed field under magnification.
And how did you assess the clearance? If you reamed the bushes too big then they won't retain the oil well.

 

Hard to see from the pictures but it looks as though the bushes are not right up to the surface of the plate?
If the bushes length is shorter than the thickness of the plate then you are losing a lot of bearing surface. Even a couple of tenths of a mm can make a big difference, particularly on a fairly modern or cheaper clock where the plates aren't very thick. You are always better off to use a slightly oversized length bush and trim it back, than use one that is too short.

 

Thanks for the answers. I have only seen the Bergeon burnishers for sale for well over a hundred euros. It would ne nice if you could point me to a £40 burnisher.

I did use ready made brass bushings. The clock in question is from the 1950´s so not very old. Maybe I should use bronze in those first wheel bushes because they seem to be under a lot of pressure.

I might have made the clearance too wide. I shall pay attention to that too in the future.

When I get a proper burnisher, I will redo those bushes and make sure that all the advise given above is heeded to.

With what the pivots should be polished after burnishing?

 

Also occurs to me that you used Bergeon bushes. Did you use their accompanying reamer to make the holes? Very important that the holes are parallel sided and absolutely at right angles to the plate. You don't necessarily need their fancy rig to do that, but you do need some way of ensuring the tool goes in straight. You could for example use a pillar drill, just turn the chuck by hand rather than under power to cut the holes. I certainly wouldn't advise trying to do it without something like that. More problematic is how to centre the tool correctly if the hole is elongated. That is one situation where the proper Bergeon set up is very good. I use a milling machine, which is even better if you have one or know someone who does. Otherwise this is quite difficult. You could use a decent, accurate, pillar drill, but you need to use a flat ended milling cutter to get the hole round and in the correct place. An ordinary drill will just follow the path of least resistance and make a bigger hole in the wrong place.

 

I don´t have the reamer + other equipment for the Bergeon bushes (maybe after I win the lottery). I did make a holder for the clock plate, though. I just drilled the hole a bit undersized and broached it to the final size and pressed the bush in the place. I used a pillar drill and filed the hole on the opposite side before drilling so that the drill would go to the correct center. I also broached the pivot hole in the bush after that because the hole was smaller than the pivot.

 

All sounds good. One tip if you are using taper broaches is to go from both sides. So the tapers meet in the middle, if that makes sense. Avoids any tendency for your bush to pop out. The Bergeon bushing cutters do make the job easier, but I agree they are a fearsome price, not worth it unless you are doing loads.
From what you say I do strongly suspect that the pivots are in need of some work.
The other thing that looks a little unusual is the very conical ends on the pivots. Nothing to do with you of course, but can't help thinking that in the inevitable fiddling to get everything together those could easily scratch the inside of the bush. Normally I would expect them to be rounded.
Do let us know how you get on.

 

For polishing a simple way to start with could be the lollipop stick again. Rub the flat surfaces down with very fine wet and dry so they are really smooth then apply polishing compound to it. The compound will impregnate the fibres of the wood. I use polishing compound for car paint, purely because I have gallons of the stuff. You could use jewellers rouge for example. Spin your pivot in a drill and just rub the coated stick over it gently. If they are already well finished then it only takes a few passes to get a mirror finish.
However you do it make sure every trace of the compound is removed afterwards.

 

OK. Thanks a lot for the info.

 

I have used the broaches from both sides. Before I started, I watched a lot of youtube videos to learn the basic techniques. I also have smoothing broaches for the pivot holes.

I think that the reason is improper burnishing of the pivots. I´ll know better when I redo them. After a year or so the results will be comfirmed (or not).

The conical ends seem also a bit rough. Not a high end clock, I suppose.