Koma 400 day clock

[Michael Brett 1Participant @michaelbrett1]

I have a Koma 400 day clock that I am repairing the main spring on. All was going well till I came to putting the hands back on . The big hand sites on a square peg so thats fine ,but the small hand is loose on its shaft. There is some sort of clutch I believe on the small hand but when taking it apart I failed to take notice of the sequence of reassembly. Anyone know what order they go on the shaft. Theres a small flat washer , diamond shaped curved spring and a sleeve that fits over the minute hand shaft, with a cog on the end.

Mike

[Michael Brett 1Participant @michaelbrett1]

small hand not moving

[Martin KyteParticipant @martinkyte99762]

If I have understood you description the curved spring should go on first behind the cog (minute wheel) with the ends facing forwards and bearing on the back of the wheel/cog. This creates the clutch as you call it and provides the drive. The hand goes on next and then the washer and finally the taper pin through the end of the minute arbor which should compress the spring a little and make everything firm as well as ensuring the drive and a degree of slippage for adjusting the time.

regards Martin

[Michael Brett 1Participant @michaelbrett1]

Thanks Martin

This is all different to the way I have it at present. Sounds promising , I will alter it and let you know how it goes.

Mike

[Michael Brett 1Participant @michaelbrett1]

Right I have the center spindle sticking up, so I place the spring over the spindle with the points facing towards the front. Next I have a small tube with a small cog on the bottom ,this holds the minute hand, if i put this over the spindle so the cog sits on the spring the points of the spring are either side of the cog . Next goes the tube with a bigger cog on, this is the hour sleeve . The spring does not reach this cog so the hour hand spins freely. Still got the washer left over. Still not working.

Mike

[Michael Brett 1Participant @michaelbrett1]

I have managed to remake the main spring arbour which was broken and put it all back together. Clock now winds and ticks. Result. Still have the problem of hour hand which just hangs down at the 6 oclock position. Tried many configerations but small hand refuses to turn.

[Michael Brett 1Participant @michaelbrett1]

Just an update.

I have been advised that there is a cog missing that goes between the hour shaft and the drive, that is why the adjuster just turns but the hour hand moves freely.

Thanks for your help.

Cheers Mike

[Peter Cook 6Participant @petercook6]

You say the hand just hangs down at 6 o clock. This is a diagram of motion work

Do you have the two connected gears on the right of the diagram. One is driven by the pinion on the minute hand. the second drives the hour hand via its gear. You don't mention them.

Sorry postings crossed.

 

Edited By Peter Cook 6 on 30/11/2022 20:23:18

[Michael Brett 1Participant @michaelbrett1]

Thanks Peter for posting that image, first time I can see how it should look. No I do not have the two gears on the right or the shaft to hold them. i can see a hole on the frame where they should be. Have got the clock working now apart from the hour hand. The minute hand seems to be keeping good time.

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