Smiths rim wind and set

transporter · Saturday at 03:58 PM

Ok, as per pictures I have a smiths rim set and wind on the bench, swimming in oil but all sorted.
The fault I have is the mainspring bridle has lost its tab/notch/hook, like a hebdomas pocket watch the mainspring is fitted to a bridal in the barrel which slides around on full wind onto 4 notches in the barrel wall, thus stopping damage to the mainspring by over enthusiastic winding.
So my questiion is this, what is the best way to create another hook in the bridal, my thoughts are along the same lines as making a new hole in the mainspring end, annealing etc, but what and how to make the hook??

I have a pair of barrel hook pliers that work great in soft brass but won’t even scratch the bridal, what I don’t want to do is whack a hole into it and not have a hook.

the pictures are of the bridal ( broken) and a hebdomas ( complete ) incase you are wondering what I’m on about. And a few of the serivce.

Thanks for any advise.

watchweasol · Saturday at 08:16 PM

Nice clock. Try annealing the broken bridle end making a hole in it then riveting it to the spring using some brass wire.as long as the outside surface is smooth it should slip easily, not forgetting the grease

transporter · Sunday at 08:38 AM

12 hours ago, watchweasol said:

Nice clock. Try annealing the broken bridle end making a hole in it then riveting it to the spring using some brass wire.as long as the outside surface is smooth it should slip easily, not forgetting the grease

Hi watchweasol, yes that is a way of doing it I suppose, I have a pair of mainspring hole making pliers on their way off eBay, the ones with the different shaped punches. I may be able to use them to make a hook.

watchweasol · Sunday at 09:01 AM

Hi. It’s either riveting or welding . I have seen some small home made welding tools on UTube at times may be I should have a go at building one, they are small spot welding machines. Suitable for the likes of these type jobs.

tomh207 · Sunday at 09:44 AM

Just did a quick google, unbelievably there are battery powered micro spot welders on amazon from about 25 pounds up. No knowledge of them, just one of the things that I find fun on this forum, often go off down a new rabbit hole and learn a bit about something I haven’t previously thought about.

thanks for the unexpected diversion

Tom

HectorLooi · Sunday at 09:48 AM

1 minute ago, tomh207 said:

battery powered micro spot welders

I'm currently rebuilding one of these and converting it to run off mains AC.

The circuit of these battery powered spot welders are not very good and it tends to drain the battery flat and kill it.

tomh207 · Sunday at 10:00 AM

10 minutes ago, HectorLooi said:

I'm currently rebuilding one of these and converting it to run off mains AC.

The circuit of these battery powered spot welders are not very good and it tends to drain the battery flat and kill it.

Thanks Hector, first time looking at these, always good to get information from someone who has had one in hand.

Tom

watchweasol · Sunday at 10:10 AM

The high voltage will take a toll on the battery but if used occasionally such a the proposed bridle welding I guess if it works it’s worth the price of a battery.

tomh207 · Sunday at 11:21 AM

1 hour ago, watchweasol said:

The high voltage will take a toll on the battery but if used occasionally such a the proposed bridle welding I guess if it works it’s worth the price of a battery.

I think it would rather be the blast of high current drain that would do the damage. But if used occasionally to maybe fix a mainspring or do dial feet it might be worth trying especially if the mainspring or a replacement couldn’t be found.

Tom

rjenkinsgb · Monday at 07:45 AM

I've tried some supposedly good battery operated spot welders - the ones I had were a waste of time for anything above thin foil. I ended up with a supercapacitor based one & that does work really well on the stuff I've tries so far.

I'll try it on a broken spring and see how it works on that material!

watchweasol · Monday at 08:42 AM

Hi @rjenkinsgb any chance of a picture of the device and information as to where they can be acquired. Thanks.

rjenkinsgb · Monday at 08:43 AM

Half an hour later: Test done.

It takes rather less power than I expected, for a fairly small watch spring at least; this measures 1.5mm wide by 0.1mm thick.

The burned edge was at 20% power, through the two layers. The good weld was single sided over a brass block, at 10% power. I've been using 15% to weld terminals to lithium cells.

The spot welder is one of these, bought from a UK reseller - ebay or amazon? They are also sold under other brand names.

https://www.seesiius.com/collections/spot-welder/products/seesii-spot-welder-with-farad-capacitor-3000f-120-gears-adjustable

It takes 20 mins or so to get up to working voltage, then a very brief time between welds - or several in a row is fine. (Around 20,000 joules [watt-seconds] energy storage; it runs from a 12V 4A PSU).