Re: stepper & driver

Doug,

Sounds like you've considered the implications of the Oak subframe,
and it will likely work since you're willing to sacrifice some
accuracy.

I personally don't think using two motors on a given axis is a good
idea... (Mariss of Gecko has also stated the problems of such a
choice.)

Having said that, there are a large number of machines both hobby and
commercial which successfully use two motor drive. But I wouldn't...

If you're going to use chain for the long axis (X, though some
mistakenly call this Y); IMO you should also use it for Y. You will
get FAR in excess of your desired travel rates, IME. Easily 240 IPM
with 2A "cheap" drives, 34V power, size 34 double stack motor, and
4:1 reduction. For cuts in the 120IPM arena... BTW, go ahead and use
a screw for the Z, it makes things easier.

Good luck, send pics when you're done!

Ballendo



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Douglas Pollard"
<dougpol1@o...> wrote:

> Hi cnc folks,
> My thinking on using oak to build a cnc router is that I

already have the wood "free". with it screwed and glued together it
will be light. Several coats of epoxy will solve most of the
expansion problems where moisture is concerned. I plan to use metal
ways for accuracy and ease of movement. The x axis rails will be
tied together with metal bars so the expansion of the wood will not
change the y axis width. Only one rail will be bolted tight to the
wood the second will offer support only but will not act as a guide.

> I have 50 ft of roller chain it is about the size of bicycle

chain # 10 I would guess. I am thinking that I will put one piece on
each side of the gantry to drive in the x axis. Each side will be
driven by a # 33 frame motor {Ithink this is the right designation?}
It's close anyway. I understand that. I that I can hook them up in
series.

> I would consider 30 to 50 inches a min. feed rate with 100

inches rapid traverse a complete success anything faster would be a
bonus.

> The Y and x axis would probably be driven by lead screw. I

see no reason that a second motor on the y lead screw could not be
added if needed also hooked up in series.

> Any comments on the practicality of hooking motors in

series would be a big help. Do you get double the power? Do they
interfere with each other? Does this overload the drivers in some
way. I assume power supplies have to be larger?

> I have seen reference to this practice on line but no real

detail as to, how.

> Doug