Internet Horology Club 185
Letting Down The Mainspring on 18s Elgin FP

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https://ihc185.infopop.cc/eve/forums/a/tpc/f/1086047761/m/988100951

September 11, 2009, 21:54
Mark G. Reitz
Letting Down The Mainspring on 18s Elgin FP
I am going to attempt servicing an 18s FP grade 73
Elgin 1894 movement Can anyone give me a tip on how to let down the spring on these full plate models??
I also have a grade 3 Wm Ellery Waltham FP I need to let down

Thanaks,Mark
September 11, 2009, 22:52
Tom Brown
Hi Mark

I am not sure on each of the models you listed but they are more than likely one of these examples.

The 1st three photos are of an Elgin, you or course need some sort of tool or stem in the winding arbor of the watch to slowly let the power down.

elgin 01

September 11, 2009, 22:54
Tom Brown
You will notice the small hole that I made a line to, while holding onto the winding tool insert a small pin type object into the little hole, this will disengage the click as seen in photo 3

elgin02

September 11, 2009, 22:55
Tom Brown
This is what you are pushing against under the mainspring barrel.

elgin03

September 11, 2009, 22:57
Tom Brown
The next two photos are a Waltham, again the same need to have something to stop all of the power from being released at once.

This type instead of the hole there is a small lever that you move that will release the click.

waltham01

September 11, 2009, 22:59
Tom Brown
You can't make out the click in this photo, it is under the plate. This is the dial side of the movement.

Hope this helps, if your watches don't look like either of these you might post a photo so we can see what you have.

Tom

waltham02

September 11, 2009, 23:15
Tom Brown
I went ahead & took one more of the Waltham with the bridge removed, you can see the other inside of the lever & how when you move it, it moves away from the gear.

Tom

waltham03

September 11, 2009, 23:22
Eric Unselt
Nice explanation, Tom. Good pics, too.
September 12, 2009, 00:02
Tom Brown
Thanks Eric, I am never sure if what I write makes sense.

Tom
September 12, 2009, 00:07
Roger J. Nolfe
Good explanation...I would add that you should turn your holdback tool in a clockwise (winding) direction while pushing on the pin or lever. This unloads the tension off the gear. Then you let the tool slip thru your fingers in a controlled let down.
September 12, 2009, 09:18
Mark G. Reitz
You have saved me once again with your expertise and excellent photos.This is why this site is the Best!!

Thanks Again,Tom...Regards,Mark
September 12, 2009, 09:56
Brian C.
Tom,
Great pictures and explanation. This will help a lot of people.
Brian C.
September 12, 2009, 13:49
Tom Brown
Thanks for the tip Roger, I knew I would forget something. That is what makes this site so good, everyone willing to offer advice.

Tom
September 12, 2009, 18:36
Edward Kitner
Tom,
Very nice "show and tell." This site is the best for getting help and information!
November 30, 2012, 11:25
Dave Turner
Just to resurrect this little instruction on how to let down the mainspring.
Exactly what I needed. I haven't done a teardown on an Elgin before. Works like a charm when you know what to do.
Thanks Tom.


Dave Turner