Lathe Carriage Stop Switch

[nova_robotics]

A lathe carriage stop switch I made. It's a quick little build that will lower your blood pressure when threading.

[Frank S]

do you have a magnetic brake on the lathe motor

[nova_robotics]

do you have a magnetic brake on the lathe motor

Kinda. The VFD decelerates the motor. The motor is not allowed to spin down under its own inertia. It's very fast. It stops so fast that it makes a clunk. But it's all electric trickery. There is no physical brake.

Also I highly, highly recommend installing a VFD. That's just a cheapo eBay VFD and it made my lathe about 700 times better. There is no comparison between the original machine and the lathe + VFD. Infinitely variable speeds on a dial is incredible (plus all the other features). I just leave it in the middle gear all of the time and use the dial.

[nova_robotics]

do you have a magnetic brake on the lathe motor

I did a quick video of the VFD operation on my lathe. The reason I bought it was because this is a 3 phase lathe and I only have single phase in my shop. The VFD takes 240v single and chops it up to approximate a 3 phase waveform. But it's so much better than that. Have a look:

[Frank S]

Thanks I'll have to look into it.
Did you add a potentiometer and the E button and off switch
Most VFD's I've seen use the up/ down touch arrows
I have a rotary phase converter to run some of my 3ph equipment.
But to stop my lathe without allowing to wind down I reverse the switch it still has to slow to stop not nearly instant like yours seems to do
making it really difficult to do single point threading. One of my lathes is a 17" and another a 26" but the 26" has a declutch.
there is also the issue of inertia, the chucks for the 17" weigh 90lbs and the chucks for the 26" weigh 250lbs or more
And I wouldn't even want to guess how much the chuck weighs on the 56" 25HP pencil sharpener, but I would never consider even thinking about trying to quick stop the spinning mass that thing can handle.
I would like to install a 3hp 3ph motor on my 12x36 Sheldon but it has a threaded spindle so that would become a problem if it stopped instantly, as the chuck would come off

[DIYer]

Thanks nova_robotics! We've added your Lathe Carriage Stop Switch to our Lathe Accessories category,
as well as to your builder page: nova_robotics's Homemade Tools. Your receipt:

Lathe Carriage Stop Switch by nova_robotics

tags: lathe, electrical, stop

[nova_robotics]

Thanks I'll have to look into it.
Did you add a potentiometer and the E button and off switch
Most VFD's I've seen use the up/ down touch arrows

This VFD has a little dial on the front, but I didn't like the factory dial so I made a bigger one and wired that in. I also added the e-stop and extra switch. But that's all purely for ease of use. I used this lathe for ages without any of those controls.

I have a rotary phase converter to run some of my 3ph equipment.
But to stop my lathe without allowing to wind down I reverse the switch it still has to slow to stop not nearly instant like yours seems to do
making it really difficult to do single point threading. One of my lathes is a 17" and another a 26" but the 26" has a declutch.
there is also the issue of inertia, the chucks for the 17" weigh 90lbs and the chucks for the 26" weigh 250lbs or more
And I wouldn't even want to guess how much the chuck weighs on the 56" 25HP pencil sharpener, but I would never consider even thinking about trying to quick stop the spinning mass that thing can handle.
I would like to install a 3hp 3ph motor on my 12x36 Sheldon but it has a threaded spindle so that would become a problem if it stopped instantly, as the chuck would come off

Yeah I don't have any gear that big. But the deceleration/spin-down time is just a setting. The VFD will drive that motor pretty hard to achieve a complete stop in the time that you've set. 0.3 second or 3 minutes, totally up to you. 25HP is getting a pretty large, but 5 HP and down is no problem for off the shelf VFDs.