ATM building a GEM

[Ina Ron Lippard Renaissance Reproductions <renrepro@surfglobal.net>]

    Were I to build a mount with limited tooling,I'd probably use SS 1" 
shafting and pillow blocks.These are sealed and self-aligning.Bolted to 
some 3/4" alum. jig plate,can make a very sturdy mount.The question I here 
a lot is how to connect the plates to each other.Since they must be as 
square to each other as you can get them,a lathe is needed.And a drill 
press.If you drill a 7/8" hole in the DEC plate and then turn down the 
polar shaft for a light push fit,you'll have a tight joint.The length of 
shoulder must be less then the thickness of the plate.A 1/4-20 tapped hole 
in the shaft will allow you to draw up the shaft tight against the 
plate.Use a square piece of alum. 2X2 1/4" thick with a hole in it for a 
washer.
Make the saddle out of alum.using the same procedure.Turn  down one end of 
your DEC shaft so it is a light push fit,around 7/8"diameter just shy of 
the saddle plate thickness.Bolt as before with alum square washer and 
screw.The holding lug under the polar plate can be welded or screwed on.You 
can drill for the two 1/4-20 bolts when you drill out for the bearing 
bolts.It's all pretty simple really.I recall this design from S&T over 40 
years ago.The shop rates for welding and machining should certainly be 
under $100.Two shafts with tapped ends plus the turning should take no more 
then an hour in a well tooled shop.
   If I did build this mount,it would be better then most commercial rigs 
on the market.And probably cheaper.Anyone with a drill press and lathe can 
do this work.
regards,Ron