Re: [CAD_CAM_EDM_DRO] ball screw lead...

In a message dated 12/10/2002 8:12:32 PM Central Standard Time,
jaskew@... writes:

> What does the 'lead' value of a ball screw mean?
>

Jaskew:

"Lead" means how much LINEAR movement there is with ONE full turn of a screw
(or nut). This is equal to the "pitch" if there is only ONE thread
("one-start") around the screw. Some lead-screws are made with more than one
"start", and these have N x pitch = lead, where "N" is the number of "starts"
on that screw. Example: if a screw has 1/8" pitch (8 threads per inch), but
FOUR starts, then the "lead" will be 1/2" per turn (that's 4 x 0.125").

Also, a "lead-screw" is a long screw in a machine such as a lathe or
milling-machine which moves the saddle, carriage, or table when the
"handwheels" or "stepper-motors" or "servo-motors" turn, as the cases may be.
The handwheel turns the lead-screws in a "manual" machine, or a stepper- or
servo-motor turns the lead-screws in a CNC machine. Simple! Right???

Jan Rowland


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