New lathe is possessed

[cannibal]

What might be helpful to post is a model number or url to the purchase page. Quite often these lathes have a common manufacturer. Sometimes we can find documentation under a different Brand name.

There's bound to be someone here that can offer help, even if it's not model specific. It's tough getting a new machine starting out when it's not working correctly.

A model number would have been a smart thing to post!
It's a Vevor MX-S716G.

 

[cannibal]

You probably won't get much help from the factory-we recommend folks stay away from Vevor stuff.
It looks from the video that there are more problems than just the pot range- motor behavior doesn't look normal.
You would need to do some reverse-engineering to fix the range issue, but you need special soldering equipment
for surface mount components like that- and you would need a schematic diagram
To me it looks like the speed controller is faulty- and there may be other problems you haven't found yet

Frankly if Vevor won't provide any service I would return the machine- get your CC company involved if necessary
You should not have to re-engineer a new machine

Vevor has definitely been less than helpful, but they are very aggressive in offering refunds so hopefully that won't be an issue when it comes to it. I kind of wish I had initially created an account here first and learned a bit more as to which brand to go with. I also can't let go of a problem or puzzle and I kind of want to figure this one out.

Vevor not being able to provide a wiring schematic for the board or the machine other than what's listed in the manual is rather concerning. I have a hot air rework station for surface mount components and am comfortable swapping components on the board but I'm unfamiliar with these machines and not having some sort of documentation really makes it hard. I think I found some ICSP headers on the board though and I might try dumping the firmware to see if there's any indicators of the problem there.

You mentioned that there might be problems that I haven't found yet, and that's a really good point I hadn't considered. I might try swapping the control board and if that doesn't resolve the issue just cut my losses and go with a different lathe. Appreciate your insight.

 

[cannibal]

After reading through the manual I see that 2500 is the max RPM. So, you are getting the full speed out of it you just don't have the fine adjustment you would get with a different value pot installed.

As far as the E-stop goes, without some modification to the machine my guess is that's how it is going to work.

Little machine shop has lots of info on mini lathes. At first glance I didn't see anything that matched your lathe but I didn't spend much time searching either.

Adding an electric brake on the lathe would be really cool! I am totally going to give that a go once I get the gremlins sorted...if I don't end up going with a different lathe.

 

[cannibal]

I am not familiar with the Vevor lathes. I have a Grizzly G0602. I have replaced the OEM motor with a brushed DC motor. I use the E Stop only for initial startup and ending shutdown. The E Stop is intended to cut all power to the machine so if there is a fault with the controller, the motor will go dead. I use the Forward/ Off/Reverse switch for normal operation. While you may be able to switch from forward to reverse instantly, it is not a good idea as it puts undue stress on the electrical and mechanical components. I always bring the lathe to a full stop before reversing. Your lathe may have circuitry in the controller that prevents reversing until the lathe speed drops below a set speed to preclude instant reversal.

As to the behavior of the speed control pot,it sounds like there is a maladjusted limit switch. When I built my speed control, I built in additional pots on the circuit board which set the upper and lower speeds of the pot. Mine is set so that a full counterclockwise rotation is zero rpm and full clockwise is 80% of maximum available rpm. (I set it this way as my controller is capable of overdriving the motor so Iimit the maximum to stay within the ratings.) Mid range is at approximately 50% rotation on the pot. More than likely, your controller has a similar system.

What you mentioned about the adjustable pots makes me want to setup two potentiometers, one with a lower resistance rating to act as a kind of "fine adjustment" to really dial in the RPM or mostly use that one in order to get the ranges I want for lower RPM. The control board doesn't have any adjustments on it which doesn't help at all but that might be because it's a brushless motor?

 

[cannibal]

I was not expecting this many replies to this question, especially not so soon. I really appreciate all the help you all are providing and the sense of community here. I hope I can give back in some way in the future.

 

[markba633csi]

Cannibal: When I spoke of problems you haven't found yet I meant mainly mechanical problems which these machines
often have in abundance
Glad to hear you have some electronics experience and hot air machine- everything is going surface mount now

The absence of any board adjustments is very user-unfriendly- you would want a torque compensation control at the very least
to optimize the motor power for varying cutting loads-most brush motor controllers have that- often called "IR comp"

If your motor uses a shaft encoder the problems might be with that subsystem or firmware block. Post the firmware if you can
get a download of it- we can take a look

You could always replace the motor and controller with something else, provided the machine itself is mechanically ok,
but it kind of defeats the purpose of buying new..and you would probably need a functional lathe to do the conversion
PS I'd like to see a picture of the direct drive with the side covers off...that might limit your upgrade options

 

[Janderso]

Welcome cannibal
Gosh, it may be a good idea to return the darn thing.
It sounds like the Vevor brand has issues right out of the box with little or no help from the factory.
Precision Mathews and Grizzly seem to have much better support.
Good luck

 

[WobblyHand]

I was not expecting this many replies to this question, especially not so soon. I really appreciate all the help you all are providing and the sense of community here. I hope I can give back in some way in the future.

We have a very good group of people here, that try to help. I've learned a lot from the generous knowledge shared here.

 

[Huub Buis]

If there are no adjustments on the board, I would replace the 4k7 pot meter for 1k2 and add a 3k3 resistor in series.
The motor is probably a DC motor that has no breaks. If so, it is normal that stopping takes some time. It also means your bearing are in good condition.
The Forward/Nothing/Reverse switch is to make sure that there is always a break before make situation. I use the same type of switch to set my mill in reverse. Don't change the rotating direction until the spindle has come to a fully stop. It could damage the controller if you do.

Vevor claims this motor has a lot of torque at low RPM. Is that the case with your motor?

 

[ChazzC]

If there are no adjustments on the board, I would replace the 4k7 pot meter for 1k2 and add a 3k3 resistor in series.
The motor is probably a DC motor that has no breaks. If so, it is normal that stopping takes some time. It also means your bearing are in good condition.
The Forward/Nothing/Reverse switch is to make sure that there is always a break before make situation. I use the same type of switch to set my mill in reverse. Don't change the rotating direction until the spindle has come to a fully stop. It could damage the controller if you do.

Vevor claims this motor has a lot of torque at low RPM. Is that the case with your motor?

Since it’s new, I recommend not making any changes, take advantage of Vevor’s return policy and go with a Grizzly or LMS Mini or Bench Lathe (or look fir a good used lathe).