Purchased a Vevor WM210V-L and the saga begins

[Aaron_W]

Yeah, the replies about lower speeds and torque on these BLDC motors have a good point.

Still and all, Chinese benchtop lathes aren't famed for their rigidity so would slapping on the extra HP really gain that much? One of the things about these Chinese machines is one pushes beyond the built-in constraints of their structural design at one's 'peril'

It is an 8", 100lb (ish) lathe so I agree 750w / 1hp seems quite adequate. The 9x20s are twice the weight and ship with 3/4hp motors.
Motor swaps on the 9x20s are usually to add variable speed not for a lack of power.

 

[m1kemex]

I think the main difference as to motor Hp required is that the Vevor only has two mechanical speeds and the rest of the speed range is handled by the electronic speed control, so you loose the mechanical advantage at the lower end of the speed range. Using a ~1-1.25 Hp BLDC (compact motor) type with an electronic speed control actually makes sense. The speed range of this model is quoted as 50-2500 RPM, so in 2 speed ranges the motor cover 50-1250 and 150-2500 per their specifications (which is actually a bit crazy). The performance of the motor will be quite anemic at the low end, typical 2 or 3 speed lathes with electronic speed control would use a motor ~2X bigger than a geared/pulley headstock. If the motor/control board burned out again you might consider tossing the electronics and motor and replacing it with something like a 900-1250W BLDC controller/motor. You also may be able to just replace the speed control;er if one knew the motor characteristics/wiring.

7X Two Speed Mini Lathe Parts | ServoMotor

All Parts Used for a 2 Speed Mini Lathe Upgrade

www.servomotorkit.com

That's the problem with electronic speed control: you really develop a range of power, rather than a range of speeds. At lower speeds the motor actually has much lower than rated HP. Inversely, at full speed it has way too much power for the size of the machine.

With belts and gears the motor always develops the same amount of power and you just exchange speed and torque. It's always 1/2 HP, at 100 rpm or 3,000 rpm.

I'm having a little trouble picturing exactly what is going on with this particular lathe but some have had success increasing rigidity by bolting a small lathe to a solid footing. I picked up a piece of 1/2" steel plate I'm going to mount my Atlas /Craftsman 6x18" lathe on.

As Long as both ends are well secured, I'd think that would help in your case, welding shouldn't be required.

You didn't bother to see the video, right?

The bed is literally missing a chunk from under the headstock. What you say works for the Atlas 618 because the bed is too long and the base plate serves as an element of tension. But here it wouldn't do anything because the top part, and the bottom, aren't connected.

 

[VicHobbyGuy]

You didn't bother to see the video, right?

The bed is literally missing a chunk from under the headstock.

I watched the video - with translated subtitles. I didn't see any proof that this cutout for the motor is actually a problem. Measurements showing the headstock moving when cutting metal with the stock (or even brushless upgrade) motor might convince me. I suppose if somebody plans to put a 3HP motor on the lathe and take 0.100" cuts in steel, it might be an issue. But, really - there must be hundreds of thousands of 7x lathes keeping hobbyists happy in spite of this 'defect'.
Ted Hansen did some tests and I recall that he showed that bolting down a 7x lathe (to anything) did not affect the performance.

That Vevor lathe with the motor around the spindle.... if anything goes wrong with the motor, the whole lathe is scrap,

 

[m1kemex]

I watched the video - with translated subtitles. I didn't see any proof that this cutout for the motor is actually a problem. Measurements showing the headstock moving when cutting metal with the stock (or even brushless upgrade) motor might convince me.

Let me guess: you believe twisting forces are just a tale parents use to scare their children.

I suppose if somebody plans to put a 3HP motor on the lathe and take 0.100" cuts in steel, it might be an issue. But, really - there must be hundreds of thousands of 7x lathes keeping hobbyists happy in spite of this 'defect'. Ted Hansen did some tests and I recall that he showed that bolting down a 7x lathe (to anything) did not affect the performance.

Compared to what? If what you say was true, then all lathes would come that way.

What that (missing) wall does is to prevent the headstock from tilting diagonally around the bed's top surface plane. That tilting produces an angular distortion, so its effects are amplified with distance. Even a minuscule amount of angular misalignment can produce a big difference at the end of the workpiece. And worse even, tilting diagonally means that it does the same in both the horizontal as well as the vertical plane.

That Vevor lathe with the motor around the spindle.... if anything goes wrong with the motor, the whole lathe is scrap,

Pretty much. But that's a problem with many lathes, not only the ones Vevor sells. I remember that a friend had a Monarch 10EE just sitting there, because it also had a special speed control and it was busted. Personally, I'd stick to tried-and-true pulleys and gears, but there always seems to be someone testing their luck...

 

[VicHobbyGuy]

Let me guess:

I will leave the guessing to others. What I would like to see is some proof, some measurements.

 

[SouthernChap]

Let me guess: you believe twisting forces are just a tale parents use to scare their children.

I doubt Vic does, but when taken in context with the overall level of rigidity of mini-lathes (or rather, lack thereof) and when sensibly working within the limits such machines, the dearth of support under the heackstock is just part of the piece and something that one cuts the cloth of the demand that one makes on the lathe.

If what you say was true, then all lathes would come that way.

As a rule the Chinese mini and smaller benchtop lathes do seem to come that way.

Every model seems to have a honking great void below the headstock to accommodate the motor.

(p.s. maybe back off the disdain in the tone of your posts a bit, mate; no need to be discourteous)

 

[m1kemex]

I doubt Vic does, but when taken in context with the overall level of rigidity of mini-lathes (or rather, lack thereof) and when sensibly working within the limits such machines, the dearth of support under the heackstock is just part of the piece and something that one cuts the cloth of the demand that one makes on the lathe. As a rule the Chinese mini and smaller benchtop lathes do seem to come that way. Every model seems to have a honking great void below the headstock to accommodate the motor.

(p.s. maybe back off the disdain in the tone of your posts a bit, mate; no need to be discourteous)

I get the civility call. Maybe I'm overreacting a little, and I apologize for the snark remark, but that's because I've been in the same position many times (I can expand on the topic, if someone is interested). Some people have this false notion that, just because they are unsure about something, then everyone else must also be unsure. They can't seem to accept that other people simply know or understand things they don't, and therefore expect others to justify themselves before them, as if they were a metric for everyone else.

There is really no debate or uncertainty about closed vs open structures. It's basic structural knowledge.

 

[SouthernChap]

I get the civility call. Maybe I'm overreacting a little, and I apologize for the snark remark, but that's because I've been in the same position many times (I can expand on the topic, if someone is interested). Some people have this false notion that, just because they are unsure about of something, then everyone else must also be unsure. They can't seem to accept that other people simply know or understand things they don't, and therefore expect others to justify themselves before them, as if they were a metric for everyone else.

There is really no debate or uncertainty about closed vs open structures. It's basic structural knowledge.

Sorry, I'm not following what you're saying by referencing the ArtisanMakes video? He certainly tries to add mass in both the bed underneath the ways and the void under the headstock with his 'epoxy granite' mix and IIRC adds a steel plate under the headstock (been a while since I watched the video) but that was mostly for vibration damping rather than rigidity.

Ultimately (again IIRC, in a later video), he concludes that there's only so much you can do to increase the rigidity of a mini-lathes and ends up buying the larger Hafco lathe.

The point I was making was that the design of the smaller Chinese mini and benchtop lathes is ultimately compromised by the lack of rigidity, and anything attempted to ameliorate that will only get you so far; the best solution is to either buy a bigger or better designed lathe, or not worry overly and work within the limitations of the platform.

Not that the mods people like ArtisanMakes or Steve Jordan or We Can Make That Better do are pointless (they'll help some and certainly increase the capability of the lathe, and if one enjoys doing the modifications, that's reason enough to do them), just that you can't make a Colchester Triumph out of a Seig C3.

 

[m1kemex]

Sorry, I'm not following what you're saying by referencing the ArtisanMakes video? He certainly tries to add mass in both the bed underneath the ways and the void under the headstock with his 'epoxy granite' mix and IIRC adds a steel plate under the headstock (been a while since I watched the video) but that was mostly for vibration damping rather than rigidity.

He's not adding weight. He's closing the structure. You might find this hard to believe, but rigidity and mass are not related. And that cross brace has little to nothing to do with vibration damping.

Ultimately (again IIRC, in a later video), he concludes that there's only so much you can do to increase the rigidity of a mini-lathes (...) you can't make a Colchester Triumph out of a Seig C3.

Of course not. But that doesn't change the fact that the lathe has a major design flaw that can be fixed to get significantly better performance.

But how are you going to fix a problem you don't understand? Someone suggested to bolt the lathe to something more solid. And, indeed, that would improve things if it was an Atlas 618, where the main limitation is the bed flexing / working at its limits. But here, the headstock is flexing relative to the bed itself. It's a different problem.

 

[SouthernChap]

He's not adding weight.

Who said anything about weight? I said 'mass'. Simplifying greatly, mass with a gravitational force acting on it leads to what we call weight, but the two aren't the same and mass has other properties than just weight.

He's closing the structure. You might find this hard to believe, but rigidity and mass are not related.

Well, leaving aside your condescending tone, and the fact that mass and rigidity are related, albeit, not in a first order relationship, I've watched this video (along with most of his others) and I'm fully aware of what he's doing.

And that cross brace has little to nothing to do with vibration damping.

Of course it doesn't. The epoxy granite he adds is there to damp vibration. The cross brace is there to provide support to the part of the bed that's under the headstock.

Of course not. But that doesn't change the fact that the lathe has a major design flaw that can be fixed to get significantly better performance.

I'd argue the word "significant". There are plenty of people who have similar lathes (particularly those who spent a little more and bought from reputable importers who don't get their lathes from Vevor) who have not made this mod and have managed to produce perfectly good work. Why? Because they work within the limitations of their lathe.

But how are you going to fix a problem you don't understand?

I understand the design flaw perfectly well, thank you. I just think that the Vevor lathes are best viewed as either a 'last-ditch-can't-afford/can't-access-anything-better' purchase (or in some cases an understandable but mistaken purchase due to lack of information).

Given this, I'd recommend using the lathe within its limitations and when one butts up against those limitations, replace the Vevor with something better, or if that really isn't possible, only then start considering modifications of this order.

Someone suggested to bolt the lathe to something more solid.

As you suggest, that wouldn't fix this design flaw, but (assuming the 'solid' something is of a material that is a good vibration damper) would help reduce the potential for the resonance build up that leads to chatter.

Anyway, I'm done with being condescended to. This conversation is over, I'd say.