Antique Clock Restoration - The Complete Job - Part 3, The Mainspring Barrels.

Welcome back to part three of the antique clock restoration video series. In this episode I'm going to deal with the motive force which is the mainspring barrel assembly at the bottom end of the train. The mainspring barrel is the unit that contains the mainspring. It's a brass barrel which contains the coiled spring and provides power to the rest of the train. In this case the barrel pulls on a gut line which pulls around a fusee and this is a device that I will talk about in another episode which is used for equalizing the torque output of a mainspring. But in this episode I'm going to concentrate on the mainspring barrel itself. This is an often neglected part of a particular fusee clock because the mainspring barrel on something like a carriage clock or a french clock would have the first wheel of the train known as the great wheel. The teeth are cut directly on the outside of the barrel so any problems with the bearings of the barrel, the bushing between the barrel arbor and the barrel itself can cause problems with the meshing of the train and in turn stop the clock. However on a fusee clock the teeth of the great wheel are on the fusee and not on the barrel itself so the barrel bearings being in very poor condition does not necessarily stop the clock and as such they get neglected. However the bearings need to be in much better condition than people imagine because every loss that you have at the bottom end of the train will exaggerate by the time you get up to the top of the train so you may have minor problems with the escapement which are being exacerbated by the fact that you're losing so much power at the bottom end. Now when a mainspring barrel bearing gets very worn the barrel has a tendency to tip over onto one side and as this becomes exaggerated it can cause a braking effect between the, by taking up the end shake of the of the barrel against the barrel arbor and also causing a drag on the bearings themselves. You've just watched me polishing the, or re-burnishing at least, the pivot surfaces on the barrel arbor and now you're looking at the condition of the bush itself. Now the bush wasn't in terrible condition but there were grooves worn into it by the grooved surface of the pivot. So after dressing down the surface of the pivot using a pivot file to smooth out all of the grooves the surface was then burnished using a pivot burnisher which is a steel burnisher used with oil to further refine the surface of the of the pivot itself and this provides a nice bearing surface. Moving over to the Shaublin 102 lathe we're going to start by machining the old bush out. I found that the best way of holding a barrel like this is in a three-jaw chuck and I put some tape around the outside of the barrel to protect the brass surface of the barrel from being marred by the the jaws of the three-jaw chuck before mounting it in. It's not hypercritical that they run with perfect concentricity but it's good to get it as good as you possibly can. Whilst on the subject of neglect another often neglected thing is the bearings of the Shaublin 102. This is a total loss oil system so it's good to give it a pump of oil before starting any turning work each day. We're getting in with a small boring bar this is a high speed steel boring bar to turn away part of the the bushing material that was that made up the original bush. There wasn't a bush in here before this is actually all turned from the original part of the of the barrel but we need enough need to cut away some material in order to put a bush in place in order to re-bush. So here we have the enlarged hole as we've bored it out and the next job will be to prepare some cast brass to make up a bush. A cast brass is a lovely material for bushing because it hardens with hammering so when you hammer up the bush it actually gets harder and makes a lovely working surface for a bush. It's traditionally what would have been used. This is my trusty smart and brown 1024 used just to rough out the bush. I rough out the bush spotting the hole with a centre drill and then drilling it out with a normal drill as a blank. They're by no means turned to size but they're turned closely so that all we need to do is tweak the holes out with a broach before they can be just to make sure that the there's something in the joint that's really going to hold on to it but the mechanical joint itself is going to be so good when the brass has expanded into the hole through hammering that I don't think it's going to go anywhere anyway. I think this is an unnecessary step but something that I've always done and continue to do so my little crutch that I hammer in the bush and then I go around and peen the bush so I'm hammering it. This is doing two jobs this is both riveting the bush into the hole and it's also work hardening the material. You can see here how the the material is compressed and the hole in the centre it got smaller. Obviously with this being a striking clock there are two barrels so you may see me repeating processes on this video as I deal with both barrels. Unfortunately I missed pressing record on stage here but I don't broach straight from the hammered hole surface I actually put it back into the lathe and take a few skim cuts to true up the bore and get it close to size and then I'm only finalizing the size for the pivot hole and the pivot size of the barrel arbor using a broach. So the concentricity is actually from the lathe. Now this is a nice little tool that was first introduced to me by Chris over on Clickspring and this is a barrel transfer gauge. So what this does is effectively measure the distance between the inside faces of the two bushes in the inside the barrel. Obviously this is a measurement that you can't physically take in a conventional way so this is essentially a transfer device. You can see me putting it inside the barrel and then you pull the two parts together so that they're flat up against the insides of the of the bushes and then you can remove the barrel cap hopefully without disturbing the transfer gauge and measure the distance that the gauge shows and that should show you the space that is inside the barrel between the two bushes. This measurement will hopefully be somewhere near the barrel arbor and you would obviously adjust by facing the bushes that you've just fitted to the barrel and the barrel cap until you arrive at a measurement where you're going to get suitable end shake inside the barrel. I like to just knock the burr off both inside and outside. Obviously the outside I tend to put a slightly deeper burr so that it acts like an oil sink. These clocks didn't tend to have much of an oil sink on the barrel but I find that it's nice to have some way of retaining a bit of oil around the the bearing. Now here I'm using an old darning needle as a burnisher and I'm burnishing the surface of the brass just to further work harden it and refine the surface. It makes the surface nice and smooth and again maintains a nice bearing surface this hopefully will add a bit more longevity to the to the bearing and mean that it shouldn't need doing again in the too near future. Back over to the Shaublin 102 and in this case to put the six jaw chuck in in order to repeat the process you've just seen in this case for the barrel cap. The barrel cap you can hold in the six jaw chuck because it's essentially a flat disc and it's a little bit easier to to hold on to but the rest of the process of bushing is exactly the same as what we've just done on the on the barrel. Here you can see in a little bit more detail the high speed steel for a close fit for the bushing but it does need to be able to slide in to give it space to move while you're peening it over while you're riveting it because the brass will expand and really grip into that into that hole. Again I tend to start it off with a bit of Loctite just to make sure that it's never going to go anywhere before hammering it home and peening it to work harden it. Now this is the step that I forgot to press record on the camera on the barrel itself this is after riveting in the bush is truing up the hole again using the six jaw chuck and a boring boring bar and I'll bring the hole close to the size of the I then just skim the top of the bush to remove the overhang. This is not strictly necessary but it tidies up the repair. I don't like to skim the whole barrel cap I like to retain as much material as possible or surface finish as well but what I'll do is to try and carefully just remove the top of the bush and bring it down almost flush with the top of the barrel cap. So assembled you can see the reconditioned if we'll call it that barrel I've got a nicely burnished barrel arbor which is a very important step and you can see me testing here for freedom and for shake. Now in old clocks shake is an important element if it doesn't rattle it won't go as they say and that is true so I'm happy with both barrels and how they feel how they sound no tight spots everything's running nicely. Be sure to subscribe and turn on the bell notification so that you don't miss part four of this series. You can also follow me on Instagram and I would very much appreciate you considering becoming a patron over at Patreon. Thank you very much for watching and I'll see you on the next video.