Re: [CAD_CAM_EDM_DRO] Re: Need help with Mill/Drill retrofit

I've been a machinist for decades, and I've had that happen once! On a
manual machine for that matter, with plain screws. I'm very well aware of
the dangers and take good precautions, and those include table locks as
indicated ... but a stepper in off/shorted mode provides a high degree of
resistance, in fact on the same order as it does when powered up and moving
the table. If someone does as I do, he can be assured that unless he sticks
it to the machine really hard, he is probably going to have no difficulties.

You may want to consider that many CNC have a manual mode, and on some the
servos are completely disconnected and essentially not even there when
using that. In a case like that, table locks are helpful. But IAC the idea
of course is to use climb milling on the one you're cranking. That way you
will have control of the one axis and the cutting action is to push work
away on the other one, and not engage it more.


At 01:29 PM 10/12/02 -0000, you wrote:

>With such high effiency the ballscrews on a manual mode have a very
>real possibility to letting the table fly the lenght to the stop.
>
>if a cutter digs in, the resultant torque imparted into the workpiece
>ergo the clamps and table, will have considderably more force than a
>shorted stepper. And the screw offers no resistance.
>
>Think of trying to brake your car on ice.
>
>
>
>
>--- In CAD_CAM_EDM_DRO@y..., bjammin@i... wrote:
>> At 07:30 AM 10/11/02 -0700, you wrote:
>> >If you use ballscrews, then you may have problems in the manual
>mode
>> >(turning the crank).
>>
>> Not necessarily. One way is to use double-ended steppers which have
>a
>> certain amount of holding even when off and esp if off and shorted.
>The
>> handwheel goes on the dead end of motor shaft. The rest of setup is
>left
>> as-is.
>>
>>
>>
>> Regards, Hoyt McKagen
>>
>> To prevent virus propogation, don't put this addy in your book
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>> Lots of people confuse breathing in and out, with living
>
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Regards, Hoyt McKagen

To prevent virus propogation, don't put this addy in your book
Belfab CNC - http://www.freeyellow.com/members/belfab/belfab.html
US Best MC - http://www.freeyellow.com/members/batwings/best.html
Camping/Caving - http://www.freeyellow.com/members/batwings/caving.html
Lots of people confuse breathing in and out, with living