Smiths astral national 17 gaining time

[Johndub]

Hi all. Little bit of advice sought. I'm new to all this, so bear with my beginner questions! 
I got this lovely Smiths Astral National 17 in a box of old parts during lockdown. The clickspring was broken and I lost the cannon pinion during disassembly. Both replaced, all cleaned and oiled. It's running, but gaining about 6 min per day, a little less dial side up. I plan to clean and oil it again. I've already demagnetized it, so i don't think it's that, but I'll do that again. 
I've read that the clickspring in these is prone to breaking - any tips to avoid this if i have to repeatedly wind/let down the spring while working on it? Same thing with the stem release button (I've already scratched the plate around it!) 
Any advice more generally on things to watch out for with this?
The movement is 606464e
Thanks all

[Marc]

Generic click springs are available from Cousins.

If it is showing as 6 min/day slow on a timing machine then it would be useful if we had more of the timing machine data (amplitude, beat error), or have you observed that it's 6 mins behind 24 hours after setting to a known standard?

I can't really see from the movement pic to be sure but judging by the relative positions of the regulator arm and the stud carrier (90 degrees apart) it looks like you may have a fair bit of scope to slow things down at the regulator.

Failing that you should visually check that none of the H/S coils are touching or sticking, remember that demagging won't unstick coils that are sticking due to contamination. Also check that the H/S is flat, parallel to the plane of the balance wheel, and not fouling anything.

Edited August 21, 2020 by Marc
Additional comment

[Johndub]

Thanks Marc. I've timed it and used the free version of the tickoprint app, so it's not a very accurate assessment, and I've no way to measure that other data. 

That's all great advice though, thanks for that, will work through it and see how i get on. I think cleaning it again, and checking everything as i go is the first plan. If nothing else it's more practice working with it. 

John

[Johndub]

2 hours ago, Marc said:

Generic click springs are available from Cousins.

If it is showing as 6 min/day slow on a timing machine then it would be useful if we had more of the timing machine data (amplitude, beat error), or have you observed that it's 6 mins behind 24 hours after setting to a known standard?

I can't really see from the movement pic to be sure but judging by the relative positions of the regulator arm and the stud carrier (90 degrees apart) it looks like you may have a fair bit of scope to slow things down at the regulator.

Failing that you should visually check that none of the H/S coils are touching or sticking, remember that demagging won't unstick coils that are sticking due to contamination. Also check that the H/S is flat, parallel to the plane of the balance wheel, and not fouling anything.

Marc, just wanted to say thanks. All it needed was regulating - being new to all this and unfamiliar with this movement, I'd assumed the position it was in was close to centre. Quick adjustment, tickoprint app now says within seconds a day, will measure it properly over the next few days, but all seems happily ticking away 

[Marc]

Nice one John.

It's a nice watch with a good English movement.  Rather a shame that Smiths got out of the watch industry.