40's chronograph service question

[vintagewaferthin]

I noticed that my 1940's Lemania chrono was running very fast(3 minutes or so) when it was sitting off of my wrist this evening. However, when I was wearing it, it was running much better, but was still a little off(about a minute give or take). What is causing such a fluctuation? Does body temp have to do with it when its on my wrist? Im assuming that the watch is definitely telling me its time for an overhaul, right? Thanks guys!

[vintagewaferthin]

Anybody?

[vintagewaferthin]

Bump. Would love some of you guys's input.

[Oboema Sesetokoe]

Better late, than never......

My Lemania 15TL from the early 40-ies has the same.

My watchmaker says it is probably because of the position of the watch, when you don't wear the watch. If you put the watch on its caseback, the balance-wheel has less resistance. Than the watch runs faster. This is the way I put my Lemania in the safe.

If you wear the watch, its position changes al the time. Then the balance-wheel has more resistance, and the watch runs slower.

Ofcourse it's more complicated, but this should be the story in the nutcase.