Re: [CAD_CAM_EDM_DRO] Maximat conversion

Nevertheless...it WAS a good pun Peter!

It looks to me like your FB2 mill doesn't have the same column as my lathe.
Mines only 2.75" diameter.
Also, the way the lathe column is built, I wouldn't be able to get a 5/8"
screw in there anyway without extensively machining the column casting. I'm
going to try doing this conversion with as few modifications as possible.
At the moment, all I need to do is add some tapped holes to the rear of the
lathe bed and saddle. If the standard screw won't work, I might be able to
bolt a special bracket to the column casting for mounting a regular ball
screw assembly.
I just ran the mill head up and down manually. Yep, it has a lot of drag
too...so maybe I'll have to go the bracket and ball screw route here too.

After doing some investigation and some measuring, I find that the worst
area to convert will be the cross slide travel.
The slot for the screw is only about .900 inches wide. That doesn't leave
much room for a ball screw. The existing screw is 1/2" diameter. There's
enough room for me to put in a precision ACME screw and a custom
anti-backlash nut. I'll plan ahead enough here (when building the motor
mounting bracket) to provide about 9" of Y travel (as opposed to the 5-1/2"
currently available) and replace the standard table with one that is about
10" wide (X) and 6" (Y) deep. That will provide about 30" of total X travel
with the lathe chuck and tailstock removed. This will also provide a more
stable platform for mounting a fourth rotary axis when I get to that point.

"Smokin" rapid travel would be virtually impossible using a worm driven ball
nut, so I did some more checking. I have just barely enough clearance
between the saddle and column to mount a 3/4 dia ball nut on the saddle. So
I can use a conventional ball screw drive and the mounts will be simpler to
build as well.

Smoke

> The existing Z axis screw on mine had a really fine pitch. 1/16'" or
>something. I thought I could run it with a 300 inch oz but I wanted to do
>some routing which required very fast movements. I ended up with a 688 inch
>oz. Vexta from Dan Mauch along with the standard 5/8" thompson screws. The
>drivers are Applied Motion Products 7080's, capable of 7 amps at 80 volts.

I

>use an old 48 volt at 40 amp(!!) telephone system power supply tweaked up

to

>52 volts. Very powerful. I get G0 moves that smoke..... no pun untended.
>
>Peter
>THRD, Inc.
>
>