It’s Horology but not as we know it Jim

If you visit any car boot sale / brocante /yard sale you will almost certainly come across old mechanical clocks that probably have a wonderful history if they could only speak.  Their previously loving owners have ‘passed on’ and the inheriting family probably don’t like the looks of the timepiece or just can’t be bothered to wind it up or it simply no longer works which is a big problem with a rapidly diminishing fraternity that know how to fix them.

Now what follows is going to disturb the purists so they should look away.

When I find a specimen that has some character or aspect that appeals to me and has no historic value I will offer the few coins being asked and give the clock a new life.  Not by repairing them in the true sense but by fitting a modern time code based radio locked mechanism.   Here in Europe we have DCF in Germany and MSF in the UK. DCF in particular has an astonishing geographic range for its signal.

The time code locked mechanisms are available from a number of sources and vary from a basic straightforward hours minutes seconds mechanism to ones with higher torque and some with a pendulum.   The pendulum is quite independent of the time keeping but does add character. As supplied the radio locked mechanisms require you to set the hands to either 12 o’clock if you are on European time or 11 o’clock if on GMT and then you pull out a locking pin on the rear of the mechanism and install an AA battery.   The mechanism will twitch momentarily and then the hands will start to rotate from the setting position to a set hour position and then hold until the mechanism gets an update from the radio signal.  Once locked to the radio signal the clock will be very very accurate.   You can check them against time.is and as would be expected they are spot on.  When clocks need to be seasonally change the mechanism  automatically updates.  When the battery dies you simply put a new one in and the clock resets itself to time.

I have modified many clocks in this way and gifted quite a few to friends and family.   I try wherever possible to retain the original hands and sometimes this involves a little lathe work to modify the mounting bosses.

There are two examples below including my latest find, an ex British Air Ministry office clock dated on the back as 1951.  I am quite pleased with how this one has cleaned up and it is now heading to France to hang in my workshop out there.

So next time you see an unloved traditional mechanical clock gathering dust give some thought to giving it a new lease of life.

dcf clock mechanism in traditional clock
1951 Air Ministry clock modified for DCF radio control
rear view of dcf clock mechanism in traditional clock
Rear view of ex Air Ministry clock showing new DCF radio controlled movement
example of DCF mechanism in a traditional clock case
Modified clock with DCF radio linked clock module

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Clocks all Change – Reading Memorial Clock

The last weekend in October is clocks change here in the UK with a one hour shift back to GMT.   For those that remember to do it, this delivers an extra hour in bed but it is a pain to change traditional clocks one hour back.   This is even more so with Turret Clocks such as those on churches and ancient buildings.   The easiest solution is to stop the mechanism on Sunday and come back to it on Monday one hour earlier to restart it.   While this is the easiest method it does upset these ancient mechanisms that have just had 6 months of stable running.  The alternative is to wind the mechanism forward 11 hours and drive those in earshot scatty with all the bell chimes one after another.

I was very fortunate to be invited by David Pawley to help him reset some of the clocks on his maintenance list and one in particular impressed me.  This is the Memorial Clock at Reading University.   The clock tower was built circa 1920 as a memorial clock to all those associated with Reading University that had not returned from the Great War.  There are some 101 names recorded from WW1 and further names from WW2 and latterly from Afghanistan.   It is a beautiful clock and a fitting memorial.   The only sad aspect was that its enormous bell is muted these days so as not to disturb patients at the neighbouring Royal Berks hospital. 

Reading University Memorial Clock

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Tower Clocks and Cooke of York

We live in a small village and the local church has a tall spire with a tower clock movement.  Some while ago my friend Dave and I were invited to have look at the workings of the clock which was quite interesting.   The clock is still hand wound twice per week and it does not have any added technology to maintain the time keeping accuracy.  This was some time ago and I thought nothing more of it.

My local village church and clock

Church clock movement by T Cooke of York in the village church

I am a member of the British Horological Institute (BHI) and attend the local meetings once per month.   Earlier this year the subject for the monthly lecture was the Tower Clocks of Cooke of York.   This was particularly poignant for me having spent my early years growing up in the York area.   To my surprise that evening I discovered that the clock here in the village was a Cooke clock.   For those interested the presenter of the talk, Darlah Thomas together with her husband have produced a book on the Cooke family containing a listing and description of the known Cooke clock installations and indeed the optical devices the company produced.  It is a splendid volume worthy of any coffee table collection.

ISBN 978-0-9573733-3-4
Turret Clocks of T Cooke of York by Steve and Darlah Thomas

So back to the story …. the village clock, a Cooke clock and I was living in its shadow.

At the meeting I met David Pawley who spends his life maintaining tower clock movements throughout the south of England.   You can read his website Tower Time here.  I mentioned where I lived and he asked if I would mind helping him with some maintenance on the village clock here in my village.   He had been waiting for the striking mechanism to wind down so the weights were fully dropped and the time was rife to lubricate and check the strike pulley system.   We spent a pleasant morning doing the necessary work and I enjoyed the experience.

During the activity David asked if I could further help him to remove the dials from another tower clock in the local area.   The tower was on a farm estate and of wooden construction.   The woodwork was in need of repair which necessitated a temporary removal of the dials and motion work.   Dave (my friend) and myself duly turned up on the day to help David Pawley and had yet another interesting time working on and removing the items in question.

What impresses me is that these clocks have run for years and years.   The technology available when they were designed and built was basic yet here are movements that keep to seconds accuracy after all these years.

I would not be offending David Pawley if I say he is not young and I would compliment him by saying that he carries an enormous accumulation of knowledge and skills.  One day his knowledge and skills will pass into history and I do not see a new generation filling that gap.   There are a lot of tower clocks in the UK and I can’t see a new generation coming forward to fill the need for maintenance.

Farm estate tower clock

Clock mechanism

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Mill Turning Jig

After a few distractions the Mill Turning Jigs are complete and I have run a test piece that is representative of a clock pillar.

Mill Turning Jigs

The jigs were both designed in Fusion 360.   One consists of a large block with space for three 10mm cross section carbide insert tools and a second block with drill and boring related tools.   I have fitted three ER16 collet chucks to this to allow flexibility of tooling choice.  Both have mountings to fit onto my 25mm hole matrix tooling plate on the Tormach.

The jig manufacture was relatively straightforward with the exception of needing a new 10mm end mill having extended length (35mm) to bottom out the ER16 collet mounting holes.   I got this from APT and the edges were lethally sharp.

Design in Fusion 360
Mill Turning Lathe Tool Holding Block

Fusion 360 design
Mill Turning Drill and Boring Jig

Trial Clock Pillar

The pillar had simple geometry as below.

Simple Clock Pillar Trial Cut

I opted to base this on  the largest pillar I had come across in any design which was formed on a 5/8″ brass rod.   I held the stock in the spindle in a 16mm ER32 collet held in a TTS holder.

I struggled a bit with the CAM for the trial as the tool geometry of the tools  I recently received from Banggood were not in the standard tool library.   I got some of the settings wrong.  That aside the result of the first run is quite pleasing.

My feeds and speeds were a bit coarse and I cringed once or twice at the tortured sound of brass under pressure.   I didn’t complete the parting off as I didn’t fancy ducking from a large piece of brass spinning lose at 5000 RPM.

Mill Turning Setup showing both Jigs in place

Zoomed view of Trial Cuts

As ever there was quite a bit of learning while making both the jigs and running the trial pillar test piece.

Drop me an email if you want more information !

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Mill Turning on the Tormach PCNC440

I just dared to hit run on my first attempt at Mill Turning.  I need to qualify this in that the first run I was cutting air above the set up.   It looked OK so I put the real material in the spindle and I got a turned part as designed in Fusion 360.   I didn’t part it off and you can see the result below.

Mill Turning set up for first trial run

Mill Turning is where you place the material you want to shape (usually a rod of some kind) in the mill spindle instead of a milling tool.   The tools are mounted on the milling table (see above in the vice) and are completely stationary but move via the actions of the table in the X axis and the spindle in Z.   The software is conned into thinking the material is really a milling tool and that the tools are the material.

It has taken me the best part of a week to work out how to model this in Fusion 360 and I have been helped enormously by watching Jason Hughes on YouTube.  It involves allocating a different Work Coordinate for the location of each tool.

If I can get this more streamlined and get some better lathe tooling in place to support it, then I will be able to turn clock pillars.   This was the last stumbling block in moving to CNC assisted clockmaking.

Tonight I am a very happy bunny.  A glass or two of Merlot with dinner perhaps ?

Update – For a full write up on the process and how I got there go to my mill turning page and download the pdf.

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