[modeleng] GHT Dividing Head

Hi,

    As there is a demand for ME related postings - I have a query about 
a George Thomas dividing head.

    I own one of these rather nice dividing heads,  but I did not make 
it,  thus I am not familiar with the intricacies of its mechanism.   I 
want to make a handwheel for the Allchin with five spokes and thought it 
might be rather interesting to use the dividing head to get the spokes 
evenly divided.   This means using the worm and wheel to do the dividing 
(not the 24 holes in the worm wheel,  which allows easy dividing into  
2,3,4,6,etc.,  but not five!).   I set it all up and I cannot see what 
holds the plate (the plate with all the holes in it) from rotating?   
Clearly if this plate is free to rotate,  then the divisions can be 
inaccurate.   Anyone have details as to how this should be stopped from 
rotating?

     The best that I can do is to bolt on the subsidiary dividing worm,  
as this engages with the smaller worm wheel which is attached to the 
plate.   However I am sure there must be another way of holding the 
plate from rotating.

    I am sure I have George Thomas's book on dividing,  which describes 
the construction of this dividing head in some detail.   However do you 
think I can find it?   Sod's Law is alive and thriving in this workshop!!

    I look forward to any input on this subject.


       Cheers,


          Roger Mason,  in a still sunny St. Agnes.

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