Hand tension design for a Hallers 400 Day

[oldetymes]

Hi folks - I am hoping someone could share what the original design was for minute hand tension on this Hallers Anniversary clock. As received at my bench, there was no hand tension. It also came to my bench without the usual hand tension spring, minute hand nut and spacer washer and it has me scratching my head as to the originally intended design for minute hand tension. I’ve made up a replacement minute hand nut and space/washer and while that helped out the hands enough to stay in position and keep time if you will they are still what I would characterize as “too loose”. As part of this effort, I also tried a variety of hand tension springs from my 400 day “spares box” but they either created too much “drag” causing the clock to stop or were of insufficient strength to be effective. The minute hand hub square is a friction fit onto the canon pinion square. I’ve considered the original design calling for a clutch spring to fit onto the center arbor on the back of the front plate and the canon pinion being crimped to provide pressure onto the center arbor but no lightbulb conclusions. Anyhow, I am scratching my send and wondering if someone could advise how minute hand tension was intended for this Hallers 400 day. See pics for reference.

All the best, Dave

 

[KurtinSA]

I've torn a couple of these down. It appears that there is a domed washer under the hand nut. This will put some tension on the cannon pinion. The tension situation on the cannon pinion shouldn't really stop the clock...it just makes it harder to turn the minute hand if the tension is too much. As long as the minute hand is clear of the hour pipe when installed, the tension doesn't really matter. It matters if it's too much as you can't turn the minute hand to adjust the time, but it should interfere with the way the motion works is set up. Unless the added tension distorts the cannon pinion.

Kurt

 

[oldetymes]

Thx much Kurt - do you recollect the thickness of the washer?

best, Dave

 

[KurtinSA]

I pulled it off the clock...it's on the shelf waiting for a display shelf...somewhere!! Anyway, the washer thickness is around 0.45mm and the "dome" part of the washer is about 1mm in height.

Kurt

 

[oldetymes]

Thx much Kurt. I'll give it a go.

Best, Dave