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Rack and Snail

RogerH

By RogerH
in All Things Clocks

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RogerH WRT Addict

RogerH

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Hi all, I have a Smiths Mantle clock on the bench. all cleaned and running well but I'm struggling with the set up of the hour train rack. as far as I can see it's set up correctly. the rack drops onto the snail ok - not in the middle but it looks to be at the point it was originally at and is consistent through all the hours. However, it won't chime past 6. the picture shows the snail at 7 o'clock but when it runs it will only chime 4 times. I'm at a lost trying to figure out how the rack works as there are 20 teeth. as the bean cam rotates it seems to move the rack past two teeth at a time. given the amount of teeth I assume this is correct to a certain extent but I can't work out what the ratio should be......or could it be something else I'm missing?

Rack.jpg

Rack2.jpg

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oldhippy Distinguished Member

oldhippy

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Looks to me as if the snail needs to be moved 1 tooth on, the rack is only just at the 7. Have you got the warning right? the gathering pallet should not be engaging the rack at that precise time, it should be free to drop onto the snail. The gathering pallet should engage one tooth at a time. 

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RogerH WRT Addict

RogerH

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Thanks OH, yes, the warning is ok and engages correctly. the rack drops ok but I'll move it over one tooth so it falls in the middle and see what happens. Interesting that it should be one tooth at a time, why twenty teeth and not twelve?

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Rodgo Member

Rodgo

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I don't know if anyone has answered this for you when you have the snail on be sure it is engaged to the cog that sits next to it with a circling on let the rack fall onto the snail. The little arm that comes off the rack must sit halfway between the the rise and next fall on the snail cam. It will automatically fall on the right hour from there.. let me know if you need any help. Really great movement the Smiths clock.. eventually bought out by Enfield...cheers..

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RogerH WRT Addict

RogerH

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so, there are a few good videos out there and I have a couple of books all which pretty much say the same thing - although you do have to be wary of some YouTube stuff as it often shows some dodgy looking practices! however, I think the problem, in part lies with the rack hook. I've attached a picture to show how it is just out of alignment and falling the wrong side of the teeth. There doesn't appear to be any signs of damage or being out of shape but a small adjustment of the pin ensures it falls into the correct tooth and chimes away merrily. I'll keep it on test and see what happens. it seems odd to me that this should happen though and I'm concerned I may be missing something else - bending a pin doesn't seem right but I can't see any other reason - it may have been caught during cleaning perhaps? does anyone else have experience of this sort of thing? am I being too cautious or do old clocks need a bit of pulling about every now and then?

Gathering Pallet.jpg

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oldhippy Distinguished Member

oldhippy

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From what you have said and shown I noticed that the part has at some point been bent which could play a part in why it isn't engaging correctly, which means you will most likely have to adjust. I agree many videos on youtube are terrible, the video one from someone who goes by the name Scottie and he is a joke to watch.  

Rack2.thumb.jpg.b5d8ed2deea106e4f629c2c3eb7cc5df.jpg

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RogerH WRT Addict

RogerH

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14 minutes ago, clockboy said:

I presume you followed OH advice by moving the snail one tooth. When the the rack drops does it drop to allow enough chimes. If you could please send a vid of it operating. 

Hi Clockboy, yes, I always follow OH advice...who doesn't! I've moved the snail along so the rack falls in the middle although, tbf, it didn't seem to make much difference and certainly didn't solve my issue. I think his latest tip about the arm may be the solution. I'll look it at again tonight and run it over the weekend and see what happens.

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RogerH WRT Addict

RogerH

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21 hours ago, Rodgo said:

I don't know if anyone has answered this for you when you have the snail on be sure it is engaged to the cog that sits next to it with a circling on let the rack fall onto the snail. The little arm that comes off the rack must sit halfway between the the rise and next fall on the snail cam. It will automatically fall on the right hour from there.. let me know if you need any help. Really great movement the Smiths clock.. eventually bought out by Enfield...cheers..

I've seen Smiths Enfield clocks before but this is the first Smith only - so I'm guessing it's an earlier version? it's certainly a nice movement. Well made and with main spring barrels that can be removed without having to take the mech apart....always a good sign!

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