# Reversing Switch in Sherline Lathe/Mill



## Dwight Ennis (Jan 2, 2008)

I'm in the process of making a couple of turnbuclkes for my CP 173 brake system, and bought a 5-40 LH tap and die. I remembered Henner had installed a reversing switch in his Sherline lathe, so I called him up and he pointed me to this page on the Sherline web site...

*MODIFICATION TO REVERSE MOTOR DIRECTION* 
I just finished the modification and it works great! I figured I'd share it in case anyone else wishes to do this.

According to Sherline's web page, this will also work for their milling machines, but as these machines have no drilling attachment or any other way to free up the spindle on the Z-axis, it may not be worth doing.

On to the turnbuckles.


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## Cougar Rock Rail (Jan 2, 2008)

Hey Dwight, I know this is a stupid question, but why did you want to reverse the direction? How did you keep the chuck from unscrewing? 

Keith


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## Greg Elmassian (Jan 3, 2008)

using a left hand tap for a turnbuckle... notice "5-40 LH tap and die"? 

Nothing can keep Chuck from unscrewing... oops... ha ha... 

Greg


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## Dwight Ennis (Jan 2, 2008)

Being able to reverse direction really helps when tapping - especially since Sherline also has infinitely variable motor speed control from zero to max speed. When doing normal tapping, it's nice to be able to reverse direction and back the tap out. In this case, I also need to tap some left-handed threads, and normal direction will back the tap out. Either way, it's sometimes handy and worth an hour's time and a two dollar switch.


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## SE18 (Feb 21, 2008)

Hey, that's the same schematic I use for reversing my battery-powered critters


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## Dwight Ennis (Jan 2, 2008)

Yeah, the switch itself is wired just like we used to wire reversing switches for train power packs for so many decades. In fact, that's just what I was planning to do... until I took the cover off the Sherline motor control and discovered not two wires running to the motor, but FIVE!!! What the Sherline drawing tells you that you otherwise wouldn't know is WHICH leads are the positive and negative leads to the motor.


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## Michael Glavin (Jan 2, 2009)

Posted By Dwight Ennis on 26 Oct 2010 09:49 PM 

According to Sherline's web page, this will also work for their milling machines, but as these machines have no drilling attachment or any other way to free up the spindle on the Z-axis, it may not be worth doing.



Dwight, 

I'm confused; "no drilling attachment" I insert a Morse taper with a drill chuck in my Sherline mills all the time, you can insert this in the lathe too as they share the same spindle... Or I use collets and or an end mill holder of the appropriate size to drill or mill stuff. Sherline also offers a "sensitive drilling attachment" or accessory for smaller stuff. The reversing switch comes in handy for the mill and lathe IMO... Its no drill press as far as rapidly moving the Z axis, but it works nicely.

Michael


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## Dwight Ennis (Jan 2, 2008)

I'm confused; "no drilling attachment"What I meant was there's no way to free up the z-axis from the lead screw. My larger milling machine has, in addition to a handwheel geared to the z-axis lead screw, an additional handle allowing the spindle to telescope about 4" or so - like a drill press. When tapping holes on it, I can use that handle to align and start the tap, and the tap will thread itself into the hole as it's able to feed at its own rate independent of the z-axis lead screw. I just pulls itself in as required. 

My Sherline milling machine has no such feature, and if there's an accessory they sell to add that feature I'm not aware of it. Either way, I don't have it, and consequently tapping holes requires messing with the feed rate. 

On the lathe,I just put the tap in the tailstock drill chuck and leave the tailstock loose so it can slide back and forth as the tap feeds itself in or out.


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## Michael Glavin (Jan 2, 2009)

Dwight, 

I got it your comment is essentially akin to tapping holes and the ability to allow the tap to float... The Sherline "sensitive drilling attachment" will perform as such; that said I haven't tried it with a tap... Essentially the attachment allows the chuck to float on the z-axis, works very well for small diameter precision drilling. 

Attachment info below: 
http://sherline.com/1012inst.pdf 

Michael


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## Dwight Ennis (Jan 2, 2008)

Thanks Michael. I wasn't aware this attachment was offered. Something else to buy. hehehe


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