PANTOGRAPH COPY TURNING
By Gerald Wingrove

My philosophy is ‘no such thing as problems’ - just a series of answers, of which you need to select the one that best suits your abilities and facilities. This can be any grade of make-it-yourself, or ask Jeff down the road if he can make it on his CNC machine. My Falls of Clyde project has produced some interesting answers to the ‘problems’ that came to light, with regards to ‘how do I make this?’

I have been working up to the ships wheel, and its 10 turned spokes - in wood. I have made these before, but one at a time in brass - this time I wanted to do-it-right, a week later it was up and running with the wheel complete and a set of stanchions for the Poop as well.

The first answer that came to mind was a copier for the lathe, and there is available a copy attachment made for the Unimat-3, principally for screw cutting - and I have one. I fitted it up and did not like what I saw, the detail is so small, my thoughts then turned to some way of magnifying the detail to be turned - and the Pantograph - I had used one in the past to rescale plans, came to mind. So a Pantographic Copier was the answer.

I took a look on the internet, where most things can be found these days, but could find nothing, so it was down to the drawing board - or rather the sketch pad, I never get around to doing dimensioned working drawings for these tools. They are all built from scraps I have available - size is not too important but proportion is. I was pleased with the end result and the general possibilities of its most versatile usage. Those with some imagination, might consider making one for them selves of there own design to fit their particular machine. With a lot of these things, once you have seen it is possible, your own clockwork brain will soon adapt the workings to your own abilities, available materials, and to what you wish to attach it to.

Basically it is four arms linked together to give a two to one magnification, the follower tracing a pattern twice the size of the part being turned. The pattern in this case a flat plate of brass, with the required shape filed to shape on one side - linked to a pointed tool trained onto a spinning brass or hard wood bar to do the turning dictated by the master pattern.


The beauty of it is that once made a new pattern plate can be filed up in minutes to produce two, 20, 200, identical copies of what ever you wish to make on the lathe. The first example up, was the ships wheel spoke, first in brass, then in pear-wood, and finally in Lemon-wood - the latter being preferred although it had to be stained for the finished wheel. In that timber I was also able to inset a brass ring on both sides, as per the original. The minimum diameter of the spoke just below the handle is 0.010”. The second try was the stanchions for around the Poop deck - Hey-presto and I have 30, all identical with knobs in the correct place, ready for drilling, for which a simple drill jig will be made. The diameter of the stem is 0.018”, still a little over scale but should not be noticeable among the rest of the detailing and rope work. These things are never as complicated as they look.


The Pantographic Copier will be dealt with in much more detail when I get around to bringing in the fully rigged waterline model of the 'Falls of Clyde' as the new 'Current Project', maybe towards the end of next year at the going rate. By then I hope to extend it's use much further as a copier, but time will tell if the new application will work out.



Falls of Clyde project and tools.

More at http://www.geraldwingrove.com/Home_Page_/Home_Page.html


 
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