Re: Home made CNC rotary table??

At 23:45 07/05/2002 +0000, you wrote:

>The Divisionmaster is similar to the Sherline unit but because it's
>more versatile it's only just reached the market.
>You can program this for jog speed, cutting speed, number of
>divisions of the reduction, backlash and motor amps to name a few
>points that differ from the sherline unit.
>It also puts out step and direction so you can drive bigger units
>with it. I have mine running a Gecko 210 on 74 volt 7 amp to run a
>big Hoffman dividing head powered by 1,100 ox in type 42 stepper.

Actually John - the Sherline indexer can do some of that stuff
too. DivisionMaster is more versatile in some ways, the Sherline unit is
more versatile in others. Primary differences as far as I am aware are:

- DivisionMaster can cope with any drive ration from 1:1 through 99:1, user
configurable; the Sherline indexer seems to support 40:1, 72:1 and 90:1,
with others as a special order.

- DivisionMaster is user configurable for motor current, up to a max of
2A/phase, and the motor idle current is also user configurable; the
Sherline unit is limited to using the Sherline 120 oz-in motor, and I can't
tell from the spec what they do about idle current..

- DivisionMaster can drive an external power stage (e.g., Gecko G210, as we
did with your Hoffmann head) using its step & direction outputs. (Both
DivisionMaster and the Sherline indexer can be "slaved" to another CNC
device - i.e., use external step & direction signals as inputs to drive the
indexer.)

- To deal with circumstances where a series of rotary moves that are not
all the same size are needed, the Sherline indexer can be programmed - you
can define 2 programmes with up to 40 steps if I recall correctly; at
present (!), DivisionMaster hasn't got that kind of programming capability.

- Two Sherline units (maybe one rotary, one linear) can also be programmed
to interact with each other. Again, that ability isn't available on
DivisionMaster.

Regards,
Tony