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Clocks, Watches/enjoying our Bentima mantle clock

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Expert: - 10/15/2009


Question

Bentima clock
We have inherited a Bentima mantle clock from my husband's grandparents. It has an 8-day mechanism, and a choice of three differenc chimes, as well as a silent mode. (the code is 1050-020)

We love the sound, and would like it to keep good time. However, at the moment it is loosing time (about 10-15 mins per day). There is a "-" and "+" on the back of the mechanism, but what do I do? I have attached a photograph of the back of the mechanism, for info.

Also, how do we get it to chime correctly for the time? Or do I have to wait until it is just before 8.30, for example, before releasing it from silent mode?!

Answer
Sian, your clock movement was manufactured by Hermle and as you say, is a triple-chime spring wound unit with a floating balance.  The regulation adjustment is on the rotating balance wheel.  The balance wheel has a three-pronged device on it.  The balance wheel is carefully held firm while the prongs are turned.  You will see a "+" and a "-" on the back of the plate.  The prongs are turned to the right or "+" to make it go faster.  It is possible that the floating balance assembly might be defective or need cleaning and adjusting.  In that case the adjustment would not be effective.  It should then be taken to a clockmaker that is experienced in working on these types of balances.

John Newman
THE VILLAGE CLOCKSMITH
Old Prattvillage
Prattville, Alabama

I forgot to answer the last question. You did not say what the problem was exactly, as far as the chimes or strike or both being off.  If it is just the hour hand showing the incorrect hour that just struck, you count the number of strikes and carefully slip the hour hand to that number and use the minute hand to set the correct time.  You do not have to wait for anything.  The chime will auto correct in one to two hours.  But not knowing what the problem is, I will give you the complete alignment procedure:

To synchronize the hands for the correct operation, follow these steps:  The minute hand (long one) will fit on the square minute hand shaft in four different positions.  Only one is correct.  The way to determine the correct one is to install it temporarily on any of the positions and move it forward, letting each chime complete it's tune until the hour chime has finished and the hour has struck.  Count the number of strikes.  Now slip the hour hand to the hour that just struck.  This positions the hour correctly.  As the minute hand was installed at any position, it might not be pointing to the 12.  At this point do not turn anything.  If the minute hand is not pointing to the 12, remove it and replace it in the 12 position.  Now install the hand nut and tighten.  I usually use a pair of pliers to carefully tighten the nut a little tighter than hand tight, but not too much.  This will help keep it from loosening in the future. Then turn the minute hand to reset the clock to the correct time.  The chimes might not be in sync, but they should correct within one to two hours.  If you have any more questions get back with me.  Good luck

John Newman  
    Questioner's Rating
    Rating(1-10)Knowledgeability = 10Clarity of Response = 9Politeness = 10
    Commentthank you! yes - at the moment the clock strikes a different time to the one shown on the dial. But I think we can re-sync it now, which would be lovely!


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John Newman

Expertise

As much as I would like to offer values of clocks, I am not a certified appraiser and will not venture into giving an unresearched guess. There is very little published information on what I consider to be the value of "modern production clocks". Considerations are what the clock originally sold for, the condition of the case and movement, and particularly the area in which you live, the demand and the economy. ALSO, WATCHES ARE NOT MY FIELD. However, I can advise the clock owner on proper maintenance of a clock to keep it running, small corrections and adjustments and how to move a clock without damaging it. I can also advise on obtaining parts for clocks. It helps if you can send any information on the clock movement which is usually found on the back plate of the movement. I have been a clockmaker for about 35 years and was plant engineer in the mid 90's and later operations and engineering consultant at Emperor Clock Company in Fairhope, Alabama. I now have my own clock shop.

Experience

One of my greatest accomplishments was traveling to China to assist a clock factory in building clocks to the standards which we required. With the proper specifications and quality control, some beautiful clock cases were built. The factory people from the wood carvers to the plant manager were very congenial, friendly and I left a lot of wonderful friends when I returned from my trips.

Organizations
Chamber of Commerce Small Business Committee

Publications
Horological Times, a publication of the American Watch and Clockmakers Instute. Collaberated column author, with Photos and ideas for clock movement conversion article.

Education/Credentials
Associate of Science Mechanical Engineering Technology Emperor Introductory Clock Repair (Eventually taught a portion of the class after becoming employee)

Awards and Honors
Small Business of the Quarter (Prattville, Alabama) Leadership Class of 2009 (Autauga County, Alabama)

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