Retainer ring on Mark VII speed dial

[Ash1562]

Has anyone had issues with this retainer ring popping off? I recently acquired a Mark VII (the 1960's vintage) and the speed runs away when I turn it and I suspect it's cuz this retainer ring is missing and it's not providing resistance to the cam.

thanks in advance to any tips & info!

[JPG]

Has anyone had issues with this retainer ring popping off? I recently acquired a Mark VII (the 1960's vintage) and the speed runs away when I turn it and I suspect it's cuz this retainer ring is missing and it's not providing resistance to the cam.

thanks in advance to any tips & info!

The retaining ring is crucial as you stated. The two bullet shaped detent pins(for lack of a better name) will not function properly unless the dial is positioned correctly by the retaining clip. Add age and decreasing spring tension by the detent pins and the M VII does tend to not stay at the set speed(the dial moves).

[Ash1562]

Thanks for the response JPG - I was able to pop on a new retainer ring and it's holding for now. I gotta remember that the machine is a 60 year old tool - so gentle hands is the way to go.

[JPG]

Thanks for the response JPG - I was able to pop on a new retainer ring and it's holding for now. I gotta remember that the machine is a 60 year old tool - so gentle hands is the way to go.

Wear of the bore in the dial also can contribute to speed slipping. The dial gets cocked by the spring tension.