Topics

Reverse operation with 10k screw spindle

Daniel Fuller
 

Hi,
Got a question about my 10k SB lathe with the 1-1/2" x 8 spindle.
Is there any way to -safely- run the lathe in reverse with the chuck to do a specific cutting operation?
On my old Jet 9x20, the chuck had a safety screw to keep the chuck from flying off in reverse.  I don't think that my 10k lends itself to a safety screw without messing up the register.
Any suggestions or do I need to forget about reverse operation?  (BTW, motor will reverse.)
Dan

m. allan noah
 

I run threaded chucks in reverse quite often. Never had one come off.
But, I do avoid interrupted cuts.

allan

On Mon, Sep 23, 2019 at 12:25 PM <dfuller440@...> wrote:

Hi,
Got a question about my 10k SB lathe with the 1-1/2" x 8 spindle.
Is there any way to -safely- run the lathe in reverse with the chuck to do a specific cutting operation?
On my old Jet 9x20, the chuck had a safety screw to keep the chuck from flying off in reverse. I don't think that my 10k lends itself to a safety screw without messing up the register.
Any suggestions or do I need to forget about reverse operation? (BTW, motor will reverse.)
Dan
--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"

Jim_B
 

If your work is less than 1/2” in diameter use a 3C collet, or 5/8" with a 6K collet. 
I have also seen small chucks mounted to a collet or Morse taper. 

I used to have a couple. 

Sent from my MacBook
Jim B.




On Sep 23, 2019, at 12:32 PM, m. allan noah <kitno455@...> wrote:

I run threaded chucks in reverse quite often. Never had one come off.
But, I do avoid interrupted cuts.

allan

On Mon, Sep 23, 2019 at 12:25 PM <dfuller440@...> wrote:

Hi,
Got a question about my 10k SB lathe with the 1-1/2" x 8 spindle.
Is there any way to -safely- run the lathe in reverse with the chuck to do a specific cutting operation?
On my old Jet 9x20, the chuck had a safety screw to keep the chuck from flying off in reverse.  I don't think that my 10k lends itself to a safety screw without messing up the register.
Any suggestions or do I need to forget about reverse operation?  (BTW, motor will reverse.)
Dan




--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"





--
Jim B

John Dammeyer
 

Since I have a Heavy 10L with taper attachment apparently the need to mount a parting tool upside down behind the lathe with the spindle turning in reverse isn't required.  Although I must say, parting off is still a bit scary.

 

But other than that, why does one need to run the spindle in reverse at all?

 

John

 

 

From: SouthBendLathe@groups.io [mailto:SouthBendLathe@groups.io] On Behalf Of Jim_B
Sent: September-23-19 9:40 AM
To: SouthBendLathe@groups.io
Subject: Re: [SouthBendLathe] Reverse operation with 10k screw spindle

 

If your work is less than 1/2” in diameter use a 3C collet, or 5/8" with a 6K collet. 

I have also seen small chucks mounted to a collet or Morse taper. 

 

I used to have a couple. 

 

Sent from my MacBook

Jim B.

 

 

 



On Sep 23, 2019, at 12:32 PM, m. allan noah <kitno455@...> wrote:

 

I run threaded chucks in reverse quite often. Never had one come off.
But, I do avoid interrupted cuts.

allan

On Mon, Sep 23, 2019 at 12:25 PM <dfuller440@...> wrote:


Hi,
Got a question about my 10k SB lathe with the 1-1/2" x 8 spindle.
Is there any way to -safely- run the lathe in reverse with the chuck to do a specific cutting operation?
On my old Jet 9x20, the chuck had a safety screw to keep the chuck from flying off in reverse.  I don't think that my 10k lends itself to a safety screw without messing up the register.
Any suggestions or do I need to forget about reverse operation?  (BTW, motor will reverse.)
Dan




--
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"


 


--
Jim B

Daniel Fuller
 

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

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