Member postings for Hawker John

I have tried to upload a couple of DXF files today and some more photos with no success, perhaps the s/w is sulking.  My wish is to make a fabulous astrolabe and sundials.  Shadows will generate DXF files which will not load into my TurboCad and also crashed my D2NC programme.  With luck I should be able to create all the circles off the top of my head with G code.  However to emulate the engraving with say multiple down strokes on a thick (bold) side of an italic letter is difficult.  I have managed to snag a high speed engraving head for my cnc, but am not keen on spending a fortune on an engraving package unless it will work to produce an excellent result.  In hand engraving the slow withdrawal of the tool looks superb and would be tedious to emulate on every letter.  Those engravings with an effect like acid etching do not match up to the best hand engraving.  There is a Swiss guy remaking these instruments, but the look of the engraving is poor.  This does not stop him charging a fortune.  He is on the web.  I have many photos of some regular and very strange sundials a lot from Germany especially the excellent Deutshes Museum in Munich which takes days to look around, has not been dumbed down, allows photography and even has a Stirling engine from a full sized submarine.  To my knowledge Oxford does not allow photography, but has some pictures on the web.  Often though one needs close ups and not large artistic pictures.

 

 Another problem is g code generation for Arabic script and the symbols used for the stars, roman characters are available from the wizard in Mach 3 and the outer divisions can be written in a few lines of code by using subroutines.  

 

Thanks for the forum info 

 

A friend of mine Sawston Steve has recently put his old Burgess electric hand engraver on his cnc and had some excellent results.   This was great for division circles especially

 

John 

 

 

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Hi

 

I am trying to generate the G code for an astrolabe for cutting on a CNC engraver.  I have the 'Shadows' sun dial generator programme from Cadrans Solaire and it will generate a plethora of dials for any latitude and longitude.  I am also interested in some of the old and beautiful dials.  The Heliochronometer was I believe used in railway stations to set the clocks.  I first saw one of these many years ago as a garden ornament being used as an air rifle target!  Polished up and lacquered they sell at Christies for £6000 approx. I have managed to get some pics. of the internals, but it needs a maths 'c...d...'  to generate the appropriate cam for the equation of time.   I could always do with a bit of help.  I can generate DXF files of the sundials and plates of the astrolabes but lack the s/w and experience to convert them to G code.  The star pointers could just be done off the top of the head with the g code as they are just a few curves.  The National Maritime museum has many on line pictures of astrolabes.

The East German sundial appeared on e bay and I snagged a few pics.  If I am correct it is an equinoctial dial with the plate in the plane of the sun's path and the shadow is generated by the circle of plastic rather than relying on a gnommon (pointer).  I live in Bedford