RE: Drilling Gazing Balls (fwd)

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---------- Forwarded message ----------
Date: Tue, 12 Dec 2006 22:33:42 -0500
From: alfred erpel <alfred@xxxxxxxxx>
To: 'Tesla list' <tesla@xxxxxxxxxx>
Subject: RE: Drilling Gazing Balls (fwd)


to all those who care,

Put a small appropriately curved doubler disc on the 'bottom' of the sphere.
Curve doubler disc with a ball peen hammer on steel surface.  (This is how
hemispheres used to be made.)   Attach it with pop rivets.  Pre-tap or
Pre-attach a threaded stud to the doubler plate.  Before curving doubler
disc, pre drill pop rivet holes (four, five or six equally spaced holes,
whatever floats your boat).  Use the doubler plate to mark the sphere .  Use
a very sharp hardened awl to puncture the (metal) sphere with a sharp rap,
and wiggle in the holes to open to the size of your pop rivets.  Use the pop
rivet as a gage to make sure you don't open the holes to big.  Pop rivets
are cheap and ubiquitous.  This will be stronger and more accessible than
all the other suggestions so far.  IMFHO.

Regards,

Al Erpel



[snippity-do-da]


> 
> We use nutsterts all the time at work when we need to screw 
> into sheet metal.