Re: ATM "Cathy James" <Cathy.James@MCI.Com>: FW: Making the first tool

[Ken Lowther <s0109366@cc.ysu.edu>]

On Tue, 5 Aug 1997, Cathy A James wrote:

>       I haven't been able to find 1" tiles at Home Depot, and
> haven't tried Color Tile yet, especially since there have been comments
> about the softness of the tiles there.  Is it safe to use the 1.5"
> tiles I've bought?  I intended to hacksaw them down to 1", but
> without a vise it is extremely difficult to hold them still well enough
> to cut.  Even if I use the 1.5" tiles uncut, I will have to cut some
> tiles

Don't cut them just to make them 1 inch.  Someone mentioned using a
dremmel with a diamond bit.  Said it cut tile like butter.  If you can
hacksaw the tile, it is probably too soft anyhow.  My first tool was a
single piece cut from a floor tile with a sabre saw with a metal bit.  I
kept water running over it to cool it down.  It took a looonnnnggg time.
Rocking the saw back and forth seemed to help.

Consider making two tools.  A single piece floor tile is good for hogging
out and roughing in the shape.  It is then set aside and used for the base
of the pitch lap later.  Glue it on the flat surface you already have.

Once you have the sphere, cast a second tool using the mirror for form.
Here the soft tiles are your friend.  It is very hard to change your focal
lenght with them.  Also, if you have to go back to fine grinding, you
don't have to remove the pitch from you fine grinding tool.


>       Finally, I am struggling with a method to hold the
> tool/mirror in place for grinding.  My original plan was to nail two
> pieces of 2"x4" into my workbench (which also will double as
> grinding stand).  Each would be sawed off about 1/2" high, with
> the grain vertical.  The third piece would be identical, but would be
> put in place with a screw.  Any simpler ways to do this?
> 

Sounds like you are talking about regular cleats here.  Leave the third
one back a little and use a wedge to keep it in place.  It is easier to
get in and out that way.

Ken Lowther  
s0109366@cc.ysu.edu
Youngstown, Ohio  USA