New Project: Spring driven "Vienna" clock.

lundi 1 septembre 2014

It has been a bit quiet around this Message Board for a couple of weeks, so I thought it might be a good time to do a sort of "Blog" about my latest project! Now don't get too excited. I work at a VERY VERY slow pace and a long time seems to elapse without much progress on MOST of my projects. I imagine that I will add small amounts to this thread over long intervals for some while to come.



Lets start....



About a year ago, I purchased a mechanical clock movement from a seller in INDIA, via a well known internet auction site. It was advertised as a Gustav Becker Time only Mantle Clock movement. It came with the movement, dial, hands and a short pendulum, although the seller did say that he thought that the pendulum was not original. "Gustav Becker" is recognised as a reasonably good quality clock maker from around the turn of last century. I thought that the "Time Only" movement would be easy enough for me to work on, so I bought it.



The seller's original photographs of my movement can be found at this link.



When I got the clock, it seemed in reasonable nick, mechanically, although the 15cm long pendulum was rubbish and the hour hand did not fit. $T2eC16J,!y8E9s2figOUBR4r,+B8EQ~~60_57.JPG$(KGrHqV,!lEFHVrvuez+BR4rbsDrJQ~~60_57.JPGDSC_0667.jpegDSC_0665.jpg



My first task was to pull the clock apart, do a "tooth count", and calculate the rate, and the proper length for the pendulum.



My calculations suggested about 33cm to the centre of the bob, but given the style of pendulum (a rather heavy "grid iron" style rod) this would have to be much longer. The final pendulum that i made is 42cm from the top of the hook to the bottom of the rating thread. This then determines the length of the case that I have to make!



To make the pendulum, I had to source some brass and steel rod from a local hobby store. I cut the centre rod to length and made a thread with a 2.5mm metric die. I made the pendulum hook out of some 6mm brass rod that I had, cut to size, filed and then made the appropriate slots to accommodate a suspension spring with my "Rotary tool" (a cheep Aldi substitute for a "Dremmel") The hook is silver soldered to the centre rod.



I turned the Rating nut on a friends small metal lathe. This was my first real lathe project. Never used a lathe before this year, so I am quite proud of my little nut. I had to make a third and fourth cross bar out of my 6mm brass rod, filed to shape and drilled. I cut two brass rods to size and "staked" them to the top one of my new cross bars, and cut and "staked the two outer steel bars to the top cross bar. I had to "Helicoil" a new thread for the centre screw in the top cross bar and helicoil two new threads for the side screws in the bottom cross bar. I could only find "grub screws" for the bottom side screws, so they will have to do. They really should be much larger and more visible. Maybe, one day, I might turn some screws the right size. For now, the pendulum works, and looks passable from a distance.



DSC_0549.jpg



Once the clock is going fine, the next task will be to attempt to make a "Vienna" style case. Stay posted!



Cheers

Walesey





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