How to repair this clock spindle?

I have been tasked with getting this Enfield clock going again…all looks good but for the escapement spindle which has worn the hole in the frame about 2 diameters

how does one go about repairing this?

Very briefly:

First … using a round needle-file “draw” the hole into some sort of symmetrical shape which is centred on the oil-sink

Then … using a five-sided broach, make it circular

Then … make or buy an appropriately sized bush, which needs to be a friction-fit in the slightly tapered hole.

Finish according to taste and your level of enthusiasm.

Lots of gaps in that description, but hopefully pointing you in the general direction.

MichaelG.

Edited By Michael Gilligan on 13/06/2023 13:17:27

The traditional way would be to bush the worn hole with a commercially produced bush from one of the clock makers suppliers or if only one to repair, turn one from a suitable piece of brass. One of the problems here is picking up the true centre but with patience it is possible. However I think that you have more problems with this timepiece as can be seen from the badly bent leaves on the escape wheel. I have only just touched on the issues here, I'm sure someone with more experience than me will be along to give more detail. Phil

Edit. Michael types faster than me.

Edited By Philip Rowe on 13/06/2023 13:28:54

Ok thanks Michael

so not just drill out using the oil sink and press a bush in ?

why the centre punch marks at 6 to 8 o clock?

.

No reason to not 'just drill it' if you can be sure of getting centre ... but the broach is traditional [no jig-borer required] and it produces a slightly tapered hole for that friction-fit.

The punch marks are probably from a futile attempt to reduce the size of the hole !

[ very badly executed, even as an example of butchery ]

.. a hideous approach, but commonly done for 'economy'

MichaelG.

Edited By Michael Gilligan on 13/06/2023 13:50:23

Not being into clocks, and not knowing any better, I would strip out the plates, line them up and use the undamaged hole in the other plate to line up for drilling. I would use a solid carbide drill which has much greater stiffness than hss and loctite a purchased repair bush in place.

A suggested Plan B popularised by William Smith.

If you can judge where the original pivot hole would have been you can use a tool called a Preacher that has three pointed prongs in a triangular format on a plate. The plate has a striking anvil.

You hover the apex prong over the point where you judge the pivot hole should be and then strike the anvil to leave two reference indents on the clock plate. You then broach out the existing worn and distorted hole from the inside of the plate and back fill with a solid brass bush. The bush is inserted from the inside surface of the plate. The bush is filed flat using a bulls foot file. If you don't want to damage the plate surface when filing then you can use a piece of 35mm negative or similar with a hole punched to match the bush diameter and protect the plate..

Once the bush is finished flush and likely invisible to see where it is, you relocate the Preacher on the two reference holes and strike the anvil to create a centre pop with the apex prong to locate the drill for the new arbor hole.

BTW the escape wheel teeth viewed through the hole in the plate look like they need some TLC

Edited By Alan Wood 4 on 13/06/2023 17:46:33

I take no side in this … but there is some quite opinionated discussion about the ‘Preacher’ here:

**LINK**

https://mb.nawcc.org/threads/preachers-tool-for-bushing-centre-location.198510/

… an entertaining few minutes read.

MichaelG.

The hole is not too difficult to recover, as has been stated, but the escape wheel is best replaced, and with that amount of wear it is likely that there are other problems elsewhere. It would be worth looking for another Enfield movement in better condition. They were well made, but not intended to last indefinitely, and they are neither rare nor expensive.

While bushing the hole, check the pivot on the end of the arbour. With that much wear in the hole I would expect a badly worn pivot that will need cleaning up. You can smooth it down to a smaller size (as long as it's not too small) but you need to compensate by making the hole in the bushing smaller.

Also remember that in clocks the "fit" between pivot and hole is way looser than an engineer would normally accept. There is a saying " if it doesn't rattle it won't run".

I restore antique clocks and I use my mill and proper size reamers but as you haven’t got that then either bush by hand or if you have a mill or even a pillar drill then work out what side of hole has worn then gently file the opposite side so it matches the wear , then use a known small centre, I have one I turned up on the lathe in Chuck or collet to centre it on hole and clamp plate while centred , drill using a short spot drill , the replacement bush must be a press fit and the bush must be big enough to allow up to a 5% tilt otherwise clock won’t run and when arbor between plates it must have end shake.

as for the escape wheel you can draw the teeth back out using a smooth pair of pliers just gently pinch the tooth with the flat part of the tooth against the one jaw then gently draw the pliers back , I have done it many times but it takes time.

I am on holiday until 17th but I may have an escape wheel and if you want me to bush it for you then you are welcome to PM me.

Dell

Edited By Dell on 14/06/2023 07:18:09

many thanks for all your replies

i have now removed the escape wheel by loosing the plate nuts and spreading the plates enough just to remove the wheel.

i was going to drill the worn bush out and then make a new bush with a backing plate that i can then bolt onto the outside of the frame so for ease of adjustment removing the wheel if needed.

its a bodge but looking at removing the frame with all those shafts looks daunting

But actually i have had a change of plan theres so many good looking guaranteed working mechs on eBay for next to nothing i bought one of those

I'd listen to Michael G on this one. Bush it exactly as he says.

Punching the hole closed then ream out to size is a bodge that will work for a while but will not win style points.

If you do much clock repair, then don't be shy of taking plates apart. It usually saves time in the long run. Now that you have a spare, practice taking it apart and together again. It can be fun especially if you are not under pressure.

The secret is lots of notes and photographs as you take it apart. Then reassembly is just a case of going backwards through the notes.

Probably a good call. With that amount of wear on the escape wheel I suspect wheels lower down the train that transmit the power will be in equally bad shape. On the bright side that will give you lots of opportunities to practice your bushing skills.

There is an interesting download from Sherline showing a technique for bushing clock plates on a small mill developed by Jerry Kieffer. https://sherline.com/wp-content/uploads/2015/09/2118inst.pdf