Buying new mainsprings

[Rixy]

I am about to order a new mainspring for the chimes on a Garrard Westminster Chime Clock. I measured the width to be 23mm and the thickness to be between 0.4 and 0.5mm (my micrometer cannot be more accurate). The inner diameter of the barrel is 48mm and the arbor has 10mm diameter. I have seen a spring in Cousins that is 23 x 0.43 x 1800 x 48 (£18.60 + vat). Would that size be appropriate?

[transporter]

Always stick with the barrel diameter ok, you could drop a little on the height to compensate for the additional strength of the new spring, just incase yours is 0.4 mm strength.

But I would be happy ordering the cousins one as a replacement. Is the old spring shot? if its still 2 1/2 times the width of the barrel diameter when relaxed and not coned then its still good to use.

[Rixy]

Thanks for that. The old spring had broken (snapped) very close to the arbor so a new one is the only option. Much appreciated. 

[oldhippy]

With clock mainsprings it's not much of a problem. As transporter has said barrel diameter. When it comes to height, inside of the barrel to just below the ledge .  The photo shows a pocket watch barrel but you can see the ledge which I have marked with a red arrow so you know what I mean.

[Rixy]

Thanks. Had a look and spotted the ledge.

Will a new spring need lubricating? I saw someone on YouTube say not to bother but that goes against my intuition.

[oldhippy]

Yes I always oiled a new spring. When it comes to oil, for clocks use Windles clock oil it is the best. 

[transporter]

This is where I respectfully disagree with OH on oiling mainsprings, i was taught by my mentor and the BHI to use Moebius 8300 grease for mainsprings. I use a round piece of metal approx 3mm thick and dip that in the grease and and spread it around the spring. Cousins do state that new springs are already lubricated but i always lubricate before fitting.

Although Windles as a clock oil for pivots etc is excellent and I do use it, even though the BHI state D4, which I also use.

Edited June 15, 2023 by transporter

[oldhippy]

I think we all have our own ways. Now Tommy Jobson who is  at the very top of the tree when it come to clock making he has a youtube site uses a spray on lubricant.   

[transporter]

Yes we do, I see too many people getting hung up on these things sometimes, I like you have seen the joys of over oiling mainsprings and I have found that sometimes the oil doesn't release the spring every now and then, almost like a high point, but anyway as you say we all have our own ways.

[Michael1962]

Hi everyone,

I have also found another option on good ole Youtube where the guy (Scottie) uses INOX PTFE hi-pressure grease. Which may be a bit of overkill as I would expect it is highly unlikely that the grease will be subject to any sort of hi-pressure load.

Is there any sort of standard or is it a try and see and then decide on what best works for you?

Thanks,

Michael.

[transporter]

just my opinion,but if you look in the cousins site for 8300 grease and read the description for what it is made for, but as we all say, each to their own:)