Re: Reverse operation with 10k screw spindle

John Dammeyer
 

As we discovered when I developed my Electronic Lead Screw, the load on the spindle motor when threading is minimal, which is why we can get away with one pulse per revolution.  Especially an AC line coupled motor or a 3 phase one with a VFD.  The spindle just doesn't change speed while threading so the threads are surprisingly accurate.

 

Threading in reverse will not likely create enough torque to unwind the chuck.  Certainly wouldn't on my 10L.  Once the chuck is tight it takes a bit of effort to break it lose.  Only a hard braking from high speed to stopped might result in the chuck mass overcoming the torque against the screw register.

 

John

 

 

From: SouthBendLathe@groups.io [mailto:SouthBendLathe@groups.io] On Behalf Of dfuller440@...
Sent: September-23-19 10:09 AM
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] Reverse operation with 10k screw spindle

 

On Mon, Sep 23, 2019 at 10:03 AM, John Dammeyer wrote:

why does one need to run the spindle in reverse at all?

I want to cut some threads with the tool upside down with the machine in reverse.  I want to cut the threads right up to a register with no "gutter" available.
Dan

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