In article , Alan Rothenbush wrote:
Too_Many_Tools wrote:
Hi,

Nice catch on the surface grinder.

Thanks. I hope it works out. I've bought multi-hundred pound lumps of
scrap cast iron for dollars per pound before.


As for swapping out its current motor, I would be VERY hesitant on
doing that. Any surface grinder worth having has a balanced
(expensive) drive motor. Any old DC motor will not be balanced and you
will be setting yourself up for alot of hair pulling trying to figure
out what is wrong with your finish. Experience speaking here...

I have to agree with him.

Yeah, that's occurred to me as well. Reading the Sanford blumf

(thanks Don !)

Oh -- good! You got it *before* I lost power for most of
yesterday. I was afraid that you'd be banging on the IP address and
reaching nothing. (You probably get up earlier than I do. :-)

there are frequent references to "precision balanced motor". One reference,
marketing crap .. numerous references, a guy might want to pay attention.


If you do finally put a suitable DC motor on the grinder, pay
attention to the no load RPM of the motor you use. We wouldn't want
you or your new grinder scratched with an exploding wheel when the
motor exceeds the RPM rating on the wheel in a no load situation.

Starting to look like a last resort. If I do it, some sort of flywheel will
be part of the solution, as well as tach feedback for speed control.

Note that even better would be a three-phase motor -- they run
smoother than the single phase which comes on the machine -- but I guess
that the relatively large diameter makes for a bit of a flywheel effect.

Note also that the belt is protected inside the housing, and is
a specific type of flat belt -- which seems to be common for surface
grinders.



Good luck with the effort and keep us informed as to the CNC effort.

I will.

Frankly, I'm surprised more people haven't done this with manual machines.
I wonder if I'm missing something here, or if I'm just the laziest guy
around.

I've been running it manually in part because I'm still
learning about surface grinding, and I figure that I learn faster with
my hands on the machine. however -- if I ever go into production on
reeds, CNC would make sense for getting the precise contours needed.

Good Luck,
DoN.
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