Smiths Enfield Mantel Clock escapement problem

[Moose]

Thanks oldhippy.

Good to hear I have enough of the basics to give this a good go. The clock is a practice piece and with all the responses here, it has given me the confidence to have a go!

As the pivot measures 2.0mm and the bush is stated as having a 2.0mm pivot hole, my guess is that I will have to broach the hole out a bit? If that is the case I also guess I will have to do this bit by bit and from both sides to get a parallel hole? Also being Sure to stop in time to allow for smoothing?

i would love a lathe like that or similar, but also recognise the very real need to learn some more stuff first. I’ll be sure sure to update the thread, if anyone is interested. If I am not too embarrassed at the result, I may even add the “after” photo to the earlier “before”. 

[oldhippy]

Be sure and safe when broaching a little at a time, a good way of checking that you have a good fit is to test the running of the wheel, with the wheel fitted tighten the other plate, spin the wheel and with the plates in you hand move you had to different angles, the wheel should still spin it also is a test for end shake, if the wheel doesn't stop you know that when its all together it is going to correctly run, If it doesn't you know you will need to remove a little more. As they say practice makes perfect. It will be nice to see the photos after you have fitted the new bush if you can take a photo of both sides of the repair, we can look and if we think it is not quite right we can advise you, if it is good which I'm sure it will be we can give you a thumbs up. Unimat lathes are always for sale on Ebay, start about £250.  

[Moose]

Very many thanks. Great tips there and I will take my time. Photos will follow (even if I nause it all up ). Hopefully I will get the new bushes and reamer delivered tomorrow, so will make a start soon after that.

Will look out for a suitable lathe - who knows eh?

[Moose]

OK - So the job got done!

I know oldhippy was interested in the end result, so in the interests of "full disclosure", here it is...

The photo of the worn bush appeared in an earlier post, so I won't repeat it, but needless to re-iterate, is was badly worn. This is my first attempt at re-bushing, so will expect to have some "opportunities for learning the hard way".

Ready to cut... I had filed a little on the opposite side of the wear t make an oval, trying to centre on the original pivot centre. I needed to fit a 4.5 mm bush with a 2.00 mm pivot hole. I bought a 4.47mm broach and a 3.97mm. The reason for the smaller cutter was that I was not sure if I could (or should) go straight to the correct size in one step. The photo shows the smaller 3.97mm cutter ready for the first cut.

First learning issue: I had a lot of issues with the broach binding in one point on the hole, causing the broach to seem to want to cut offset from where I wanted it to go. I started wondering If I should have started broaching with an even smaller size first. Maybe someone could advise...

In the end, I managed to get the cut straight (I was hoping anyway) but in the process managed to damage one side of the cutting edge, near the tip of the broach, where it caught on the side of hole and started to dig in.  Almost certainly knackered a £14 broach, but there you go, everyday is a learning day!

Edited April 5, 2020 by Moose
spelling

[Moose]

Next step, was to take the hole out to the wanted size of 4.47mm.

Although I had damaged the smaller cutter in the process of the initial step, the broach had worked correctly as I learned how to use it and the hole looked great for this next step. I was cutting from the back of the plate, as required,  and using the new broach worked as I now expected it would. This photo shows the resulting hole once done, with hole now ready to accept the new bush.

[Moose]

The bush was fitted from the inside, again as required, without issue.

I have an engineers flat surface which I used to get a true fit. Also, I had an appropriate sized flat headed stake in my staking set, so fitting the bush was a straightforward job.

Apologies for the photo from the outside of the plate, as the focus point was off.

[Moose]

Next step was to broach the pivot hole out to fit the pivot on the wheel. This was another "first" for me, so I read up, took my time and went for it. Cutting slowly from both sides, bit by bit and constantly try-fitting the wheel to check for fit and to make sure the hole was true. Also, refitting both plates with the wheel fitted to ensure there was no binding points.

Finally, using the smoothing broach to harden the pivot hole, bearing surface.

[Moose]

Finally... Bush fitted - hole broached to the needed size, and the video below was the test fit to see if it all worked and looked OK.

The wheels spins smoothly though all angles (it was not lubricated at this point) and the bearing endplay looks fine too.

Not shown in the sequence but done anyway, was my attempt at polishing the pivot from the worn side. It was marked and oldhippy said it really should be done. I did not have any correct tools for this, but did have some hard pith wood and very fine rouge, so had a go with that, using a small hand-drill to spin the wheel. Before and after through the loupe did show a marked improvement, so was worth doing. (Naturally, I polished the pivot before broaching the pivot hole...)

All I need to do now is to rebuild the works and sort out the escapement depthing and, hopefully, this old clock will keep time again.

I would welcome comments, views on the process etc. as this was a learning task for me. I also have to say thanks to all who commented and gave tips earlier, as you certainly gave me the confidence to "have a go".

[oldhippy]

If the broach starts to bind in the hole a little oil will help. For your first attempt you have done well. I’m not too sure of the bush you have chosen the hole has very little depth to the pivot and plate. This is why I always made my own. Here are two sorts of bushes that I recommend. Bergeon and KWM I wouldn’t use them. Bergeon clock brooches cutting and smoothing are one of the best, I don’t think they cover the sizes you would need for Longcase (grandfather) clocks I might be wrong. There is another type of bushing when you have experience, that is called invisible, that is when you can’t see that the clock has been bushed.   

 https://www.cousinsuk.com/product/mantel-clock-general

https://www.cousinsuk.com/product/english-clock-bushes

[Moose]

Thanks for the reply and comments.

Noted on the oil for cutting, that's certainly a lesson learned. I used a little oil on the second cut, and a thin wipe of oil on the cutting broach, once I had learned from the original mistake!

The bushes I used are shown in the screen grab. They may have been a bit shallow, but they already had the oil sink and I did not have a tool to cut one. I guess If I had a bit more experience in this, I would have chosen differently. Still, very good to know what alternatives there are.

The broaches are almost certainly too small for anything larger, I agree. Now you have peaked my interest - invisible bushing? I had come across screw-in bushes... Off now for a read-up!

Many thanks for your support and kind words (and, to all who commented). I doubt I would have even attempted it otherwise. Now I have, I have learned something new and hopefully (when I get all together again), will have a working clock at the end of it.

Edited April 5, 2020 by Moose
spelling

[rodabod]

Moose, that’s great work. Well done. 
 

I now realise that you were possibly using a fixed size broach/reamer rather than the typical tapered type. I think the latter possibly makes your work easier, especially when you need to use an odd-sized or roughly turned bush. 

[Moose]

Hi rodabod and thanks for the comments.

It was a tapered one as it happens, but I'm thinking I went in too aggressive with the first attempt, and no oil, which did not help at all. Maybe, I should also have started with a smaller diameter reamer, not sure about that though.

But I am pleased with this, as a first attempt. With more practice I hope to get better at it.

[watchweasol]

Hi Moose     A cracking job well done, Its a bit daunting the first time as there are so many things to go wrong but with care and attention to detail  its doable , so well done you, another  lesson learned and another skill.

[rodabod]

Ah, understood. It’s quite hard to keep them centred when you are initially working into the oval. A bit like trying to drift a drill bit. I’ve also made the mistake of over-enlargening when broaching. I’ve done the same on watch cases when replacing pendant tubes which is even worse. 

Old Hippy makes a good point about the surface area available in your new bush which is probably less than original, and already quite thin due to the plate depth. But for this clock, I’m not sure it matters much. The other factor is the quality of the bush. Some are much harder than others, and some are made of crappy free cutting brass with too high a lead content. Also, they do work-harden if you hammer them. Time will tell how long any bush lasts. 

[Moose]

6 minutes ago, watchweasol said:

Hi Moose     A cracking job well done, Its a bit daunting the first time as there are so many things to go wrong but with care and attention to detail  its doable , so well done you, another  lesson learned and another skill.

Thanks for the support. every day is a learning day!

[Moose]

3 minutes ago, rodabod said:

Ah, understood. It’s quite hard to keep them centred when you are initially working into the oval.

I also think that's what it was. The broach was going too deep initially into the oval, when it corresponded to the half-section of the cutter. When I kept turning, it dug itself into the plate.  I was horrified at first and tried backing off and turning again, but it just kept finding the notch I had cut. 

I retrospect, I should had stopped and filed the cut part smooth again and then restarted and been more careful - as well as oiling the damm thing. I have no idea why I forgot that part 

Anyway, I am quite pleased with the result and it has certainly upped the confidence levels a fair bit. Just need lots of practice.

[oldhippy]

Five sided cutting broches are the best for clocks. These are very good.

https://www.eternaltools.com/clockmakers-cutting-broaches-set

 

[Moose]

1 hour ago, oldhippy said:

Five sided cutting broches are the best for clocks. These are very good.

https://www.eternaltools.com/clockmakers-cutting-broaches-set

 

Many thanks again. They do look like good value.

[Moose]

It works!

I got the pallet depthing sorted after a couple of attempts and then got it acceptably into beat. Then got the chime sorted out, so it was bonging the correct number of bongs when it should. Then back into its case. Finally, a bit of “rattle can” gold paint for the hands and a final polish on the Bakelite case.

I now have it running for an extended test to check timekeeping and also to see what sort of reserve the mainsprings give me.

Very pleased with the result. I know it’s on only a cheap Smiths Enfield, but it also represents new skills picked up, new tools experienced and new knowledge obtained. Many thanks to all those who commented and provided hints and tips. 

[oldhippy]

Nice job. You don't get much of a strike sound in a Bakelite case its more of a dull thud. A good sound can depend on the shape of the case and the wood it is made off. The gong can also pay a big part. Normally a clock with one key hole is a timepiece, two its a strike and three its a chime. There are some movements where the strike will wind up the chime as well, so you only have two key holes but you have a chime movement.

 

[Moose]

Thanks oldhippy. It certainly feels like a little win.

After reading about a bit, I found out how to adjust the hour wheel so that the the pin fell in the correct place, and also how to adjust the gathering pallet position so that the relevant tab on the rack hook dropped into the stop position correctly. All of which, I am sure, is pretty routine for more experienced fettlers, but entirely new to me.

I checked it last night and after about 6 hours, it was running about a minute fast, which seems pretty good for not having regulated it yet, but I’m guessing it was not far off the last time it was running.

What would be an acceptable rate for these old clocks? And, do you have a good methodology for regulating? 

[oldhippy]

Your clock movement is known as a rack striking movement. It’s a strike, the hour wheel with those ridges on it to determine how many times it will strike is called a snail. The strike side wheel next to the fly (that’s the flat one right at the end of the train, the wheel with the little pin in it, that pin needs to at about a quarter to or 10 to so it has good warning, make sure the hammer doesn’t start to lift in the warning passion. There is no easy way of regulating a clock it depends on the mainspring it is a trial and error, this sort of movement should go for 8 days on a single wind, if you can get it down to a minute a week that would be good.   

[watchweasol]

Hi Moose  It matters not the value of the clock , It had a fault which prevented it from running properly and you addressed the problem and in doing so you have learned a lot in the workings of a clock, far different than a watch but similar. They both achieve the same result in telling the time but do it in a different method and as such require a different approach, so you can be well pleased with your self in attempting the unknown and winning  so a big pat on the back for that.

[Moose]

Continued thanks to all here for the kind words.

i still have a bit of fettling to do yet. It’s timekeeping is good so far, at a steady rate of 4 mins per 24 hours. So that just needs a bit of patience with the regulating screw, I have no issue with that.

the bit that’s giving me a bit of a head scratch is the chime...

I have noticed one or twice that it can chime the wrong number. So for example - 1.00 it chimed once. 2.00 it chined twice.3.00 it chimed three. THEN, 4.00 it chimed five. 5.00 it chimed six times.

i had not done anything in the meantime - its cased.

i can understand the mechanism enough to get how it might be out all the time, but not correct three times in a row, then go wrong. Maybe an issue with the snail, so I will have to have a closer look and see if I can get to the bottom of it.

[watchweasol]

Hi  might have to pop it out of the case again. might as you say be a snail cam problem as the rack tail has may be landed on the 5 step or the rack lock when it counts it back has not held and slipped one but I would think that would have affected more than just that need to see the front plate with all the levers.