Re: [CAD_CAM_EDM_DRO] Re: Ball screws

Jon:

On my Bridgeport clone Ballendo is right. I once had to buy a new acme Y
nut and found it was left hand.

Works like this. If I grab the X shaft and twist it the table moves in
the direction of my thumb (like the right hand rule). For the X a
clockwise motion screws the lead screw into the nut moving the table
away from you. Same for the Y, if I grab the Y shaft and twist it the
table moves in the direction of my thumb. But, if the screw were right
hand, a clockwise twist of the lead screw would turn the screw into the
nut bringing the nut and table towards you. But since it is left handed
a clockwise twist moves the table away from you.

The difference is that in moving the X you're moving the lead screw, in
the Y you're moving the nut.

I hope this makes a little bit of sense, I have trouble with such
gyrations. Must be mechanical dislexia. :-)

Hugh Currin
Klamath Falls, OR

On 12 Nov, Jon Elson wrote:
> ballendo@... wrote:
>
>> Hello,
>>
>> Just thought I'd throw into this thread the fact that often/nearly
>> always the Y axis screw of a mill is a left handed thread.
>
> Huh? On a Bridgeport, at least, the Y screw is Right Hand. When you
> turn the handle clockwise, the saddle moves toward you.
> I suppose on machines where the crank is attached to the saddle,
> rather than the base or knee, then it would be as you say.
>
> Jon
>
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--
Hugh Currin, PE
Oregon Institute of Technology
Klamath Falls, OR
voice: 541/885-1649
fax: 541/885-1855