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Clocks, Watches/Hermle 340-020 adjustment screw


I recently replaced the Hermle 340-020 movement in our mantle clock and I'm having trouble adjusting the clock speed.  The adjustment screw feels rather tight and will only turn approximately one revolution in either direction.  This is not enough to regulate the clock adequately.

Is there a way to loosen the adjustment screw?

Thank you.

might be just tight - too tight from the factory

however there is an arm that rests on the top of the screw threads of the adjustment screw and you can lift the right end of the arm off the screw threads using your finger tip and move it manually in or out to the single thread that will match best and then be one turn either way for the final tuning using the screwdriver

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Kenneth Saunders


any mechanical clock question -no watches- no battery clock questions and no appraisals-ie: "how much is my clock worth?" type questions please! Attach a photo if possible and note all markings on the rear of the mechanism- thanks 40 years as a professional clock repair person- still a full time clock repair service owner


43+ years as a professional clock repair person- still a full time clock repair service owner.



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Comment - On a scale of 1-10, I would give Mr. Saunders a 15 on each category. His responses were clear, addressed my questions and concerns in a way that even I could understand, and even sent a picture. He explained what I had and how to resolve the issue. I was amazed at how quickly he replied to each on my e mails. He shouldn't get a gold star, he should get a whole box of them!!! Thank you Mr. Saunders, I will keep you on my e-mail "speed dial". Comment - Ken answered my question regarding how to adjust the proper striking of the hammers on my Grandfather clock within a few minutes of my sending the question to him. He answered my follow-up question the next morning. I would rate him higher if there was a number larger than ten in the selection box. Thanks again Ken Comment - I RECEIVED AN ANSWER WITHIN AN HOUR.OUTSTANDING SERVICE.YOUR RATING SHOULD BE HIGHER THAN 10. Comment - This Man is Fantastic...there is no Scale for a him...if there was...He'd beat the top of Smile....I could never ask for more ....this Man is his Score....

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