Gruen 440

[omgiv]

Hi Guys,

I am back again and am hoping to pick a brain. I had an old Gruen Curvex in my parts drawer that wasn't running and was missing a crown. I have cleaned and inspected all parts and everything looks okay. I replaced the mainspring with and new (old blue steel) mainspring in great condition. It started working great but is gaining like mad. The amplitude is around 300 degrees, the beat error is about 2, and the rate is +233 seconds. The regulator also seems to have very little effect on the rate. I checked that the pins are not too far apart and they looked okay to me. Tight but not tight enough to bind the hairspring when moving. I checked that the hairspring was caught on the center wheel or regulator pins. I made sure there was no oil on the hairspring and demagnetized it just in case. I also checked that the balance wheel had all of its timing screws. It does look like the overcoil might possibly be hitting on the center wheel teeth. I understand that if this happens, the rate will increase but wouldn't you also see poor amplitude? I am going to see if is indeed hitting the center wheel when I get my new microscope set up :). In the meantime, is there anything else I might be missing? My thoughts were that maybe someone may have replaced the hairspring or one of the gears with the incorrect number of teeth. I am leaning more towards the hairspring though. Thanks in advance for any ideas.