A recent post questions what a watchmaker meant when they said "Half-Speed Tested without a Hairspring".

https://ihc185.infopop.cc/eve/forums/a/tpc/f/1086047761/m/8691036923

Sometimes when I have to re-staff a watch such as this Hamilton 940 I just did,I test if the restaffing has been done successfully by letting it run at half speed without a balance (hair) spring! enjoy! IT WORKS!

http://vids.myspace.com/index.cfm?fuseaction=vids.individual&VideoID=48164635

WoW!!Dave

How wierd is that....

Interesting though.

Jerry

I don't know, but I've been told that the earliest watches did not have hairsprings at all, but ran entirely by the actuation of the escapement.

Great Job Dave...and nice video. What makes this even more amazing is you have to remember that everything has to be pretty much perfect to allow this to happen. That's not so hard to do with a brand new watch, but now try it with one that is 100 years old!

Good Morning David and All,

just a curiousity for the moment, why that is called ''half speed test'' , is that really half speed compared with when the hs is on?
I have been speculating about that before and I wish we could go a bit dipper in that if you do not mind....
Tnks and brgds

Enzo

Enzo, the wheel has to "spin" 360 degrees between reversing direction. Also it is not "resonating" (or "vibrating" in conjunction with a hairspring, but rather "beating" against the pallet fork. So it is traveling farther and "ticking" more slowly, maybe "half speed".

Hi David,

many thanks and sorry for late answer but I accidentaly cancelled my answer and here i had to write it again...

Yes, at the end of its travel the elipse of disk bumps against the horn of the pallet fork standing on the stop and receives an elastic reaction for to travel back...

Shall we try to find out that speed (together with the speed of the balance with the h/s ) even if it is an useless exercise.... ?

tnks rgds


Enzo

Enzo, I hesitate to do this very often unless I am very sure that all is correct because I fear that this over-stresses the Roller Jewel pin. Tha Hamilton 940 has a very big pin and that is why I did it with that watch. By the way that watch is keeping time within 5 sec av./week in Pendant up position .

Hi David and all,

Happy Holidays !!!

Tnks for your comments and I fully agree with you. What smooth performance has that watch!!!
I wish we would have time to continue this topic sometime...
rgds

Enzo