Re: [CAD_CAM_EDM_DRO] Re : minimum work CNC conversion

Horace, T.L.Ho wrote:

>
>What best results in precision we can get for such a converted
>machine ?
>
>
>

That is very hard to answer. If you start with a well-built machine in good
condition, such as one of those legendary Bridgeport BOSS machines with only
100 hours of use, and do the work carefully, it will be VERY good.

If you start with a worn-out, poorly-made clone machine, use the cheapest
parts available, and leave belts and bolts loose and things in poor
alignment,
then the results will be poor, too.

But, there's way more to it that just the machine and the conversion.
Machining
is a science, and you have to do everything right to get the best
results. You have
to use the right material for the job, the proper cutting tools, the
proper work
holding and tool holding technology, be constantly aware of the effects
of temperature
changes, etc.

Just for a data point, though, I routinely make parts to +/- .003" with
no correction
on a 1938 Bridgeport manual machine that I converted to CNC. This was
my first
CNC conversion, too! This machine has significant wear on the ways. I did
put high quality, but used, anti-backlash ballscrews in it.

See http://pico-systems.com/CNCconv.html for some very old pictures of the
retrofit. (I'm not using that hideous old Allen-Bradley control
anymore, thank
goodness!)

Jon