Re: ball screw conversion

Bryan
Ball screws do not work well with hand cranks. Due to their low friction and low tpi they are not self-holding and any force on the table will cause them to rotate. Unless you lock the table you would not be able to let go of the handles when milling. There are probably work arounds for this but you are still stuck with the low tpi.

With a 10 tpi leadscrew a complete turn is 0.1" and with a 100 division collar you can adjust to 0.001". With a 5tpi or less ballscrew it would would very difficult to get 0.001 manually.


ACME leadscrews with higher friction and higher tpi are self holding.

JohnW

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Bryan Mumford <ng1@...> wrote:
>
> I don't know what this means. I'm only aware of kits from places like
> Hiwin and Rockford. Are these what you mean by "ready made"?
>
> I can't see any description of how to install them at the Hiwin web site.
>
> Also, a friend of mine said ball screws would eliminate my hand
> cranks. I often rely on manual operation and would not want to give
> them up. Must a ball screw conversion always eliminate hand cranks?
>
> -Bryan
>
> At 1:06 AM +0000 11-27-09, fortino tan wrote:
> >Unless you have experiences how to set them straight for each axis
> >and align them perpendicularly, I suggest
> >buying them ready made will cut off all the hazzles along the road.
> >
> >fortino
> >
> >
> > Thanks. What I want to know is how hard it is to install them,
> >and if I'm going to end up with a broken machine instead.
> >
> >
> > > hiwin does have ready to install X-Y ballscrew for manual
> >retrofit. Check this link :
> >
>