Major? Spindle play

[Andy_GParticipant @andy_g]

Posted by Ady1 on 02/05/2023 10:36:13:

I haven't seen lathes or welders on Vevor UK for quite a while now

I used to visit them regularly but gave up trying

Edited By Ady1 on 02/05/2023 10:40:16

The customs & trading standards people have destroyed / blocked quite a few Vevor items:

Office for Product Safety and Standards

(No, I didn't know we had one, either.)

[JasonBModerator @jasonb]

Ah that is why I could not see any lathes on their site.

There is a video of the one on Ali running.

[Howard LewisParticipant @howardlewis46836]

IS the play in the Spindle bearings, (Check with a Morse taper abor direct in the spindle ) or just when the chuck is fitted?

It might be that the chuck is not seated properly, there may be excess clearance between flange and chuck register of the chuck may be faulty.

Rewmove, clean and check, refit chuck and recheck run out / play

If the chuck registetration is slack either the spindle flange is undersize or the chuck register is oversize.

Either way, the faulty item should be rejected and returned for replacement or refund.

Either way, not a boster for confidence in the supplkier, or the products that they sell.

Would a refund and change of supplier be the way to go?

Howard

Edited By Howard Lewis on 02/05/2023 14:29:33

[Dave HalfordParticipant @davehalford22513]

Claims a 1.26" hole through the spindle so must have gears.

Don't let your dog chew parts of your lathe anymore it invalidates your warranty.

[Ian PParticipant @ianp]

Posted by Dave Halford on 02/05/2023 16:25:53:

Claims a 1.26" hole through the spindle so must have gears.

No must about it, hollow shaft motors are available.

Ian P

[JasonBModerator @jasonb]

No sign of gears on the AliX one

This is the usual far eastern headstock just an empty box with bearing pockets each side

This is the one with built in motor, note the large hollow housing between the plates and the left end has a large flange to allow motor to fit inside casting. Controls built into the back. Go search for it on google (images will find it)

Edited By JasonB on 02/05/2023 16:55:23

[Howard LewisParticipant @howardlewis46836]

Pushing against the end of a 30 mm x 300 mm long workpiece is exerting a lot of levereage on the chuck.

It is probably at or near maximum capacity at 30 mm. Are you sing the appropriate jaws for the job?

A piece 300 mm long is only gripped in the jaws by a short length, so you could be distorting the workpiece as well as chuck comonents. Presumably your chuck is either a 80 mm or at most 100 mm?

Push too hard and you could do some damage to the chuck, at least, if yuou haven't already!.

Maybe you should repeat your tests with something a little smaller and shorter .

The reults might be a little more realistic for a minii lathe.

0.15 mm at 300 mm is almost 6 good old Imperial thous, so close up to the chuck with a smaller diameter arbor you may find a lot less .l

You must determine where the play is.

Within the chuck, the chuck / flange interface, or the spindle in the Headstock.

By exerting a lot of leverage, you may be straininbg the chuck minternals. There has to be clearance between each chuck jaw and the body; beteen each jaw and the scroll, and between the scroll and th chuck body.

Force each of those by excessive force and you will get a high reading.

You aspire to be an Engineer, not Mr Universe!

Until you find where the play is, you cannot solve the problem, even if the solutionn is to reject the lathe or the chuck.

Carry ouyt a few checks without using excess length or force, and give us the figures.

You may then get some comments which will help you decide what to do next

Howard

[Chris MateParticipant @chrismate31303]

Looking at how professional machinests handle a say 300mm bar setup in any chuck, they tighten jaws, then check runout near chuck, in case of 4-Jaw if that set to near zero runout, they go to far end near tailstock and if it has now runout, they tap it in place, go back near chuck reset if necessary, go back to far end and retap it if necessary, a repeat process till satisfactory, important if stock is already near measurements to turn to.
I say this because this illustrates how you an manipulate a piece clamped in the chuck without adjustjing the jaws, which on top of that indicates to the function of the jaws clamping anything with enough lenght to matter and can be tapped right at far end, so the faws dont clamp perfect at lenght nessarly, even on most expensive heavy duty lathes..

The 2nd thing is if you start making/turning anything you wanted to make using the lathe as you got it, how does the results turned out to yor satisfaction measuring it, including your experience-? Are you happy with thos manufactured by you results-? One can theorise a lot about accuracy without making anything.

The 3rd thing is if you clamp the lathe down, you open another can of worms regarding the accuracy of flatness and strurdiness during temp changes of that base and how that will influence your lathe accuracy. You can bend the bed if not carefull to what you clamp it down to.

[HuubParticipant @huub]

If the spindle has 2 lock nuts or a slitted nut, than it is probably fitted with contact angle bearing that can be adjusted. Unlock the nuts and adjust the play by locking the nut (just use your fingers, no tools). This will apply some preload on the bearings and will reduce/eliminate play.

When you measure play, place the indicator on the top of the head stock, not the bed. You don't want to measure bending of the bed or play because the head stock is not tightened to the bed or the chuck is lose.

Put a bar in the spindle, lock the spindle and measure the play close at the spindle. Measure the horizontal and vertical play. To measure play, you don't need a lot of force. 2 kg/4 lbs is more than enough.

You can also check the documentation about the type of bearings used in this lathe.

A picture of a slitted nut, my favourite for locking/preloading contact angle bearing shaft.

 

 

 

 

Edited By Huub on 02/05/2023 23:18:22

[Neil WyattModerator @neilwyatt]

Posted by Peter Parkes 1 on 02/05/2023 08:30:55:

I do think vevor will talk to me. They assured me they would help if i had any issues.

But as far as i can see, the only adjustment is going to be tightening down the nut on the other side of the headstock. And there doesn't seem to be any runout so I'm not sure how much i could tighten them down without causing binding. …which is why I'm asking about other options. They may just be cheap bearings. In which case replacing them with new cheap bearings is not going to be much of a solution.

I can try to get vevor to upgrade them but im not sure how that'll go. Which is why I'm wondering whether i may actually have to upgrade them in the end. Its not something i want to do, but…

What I really need to know is whether this is as serious defect as i think it is or whether Vevor are likely to tell me "no, thats normal. It will settle down with use" or some such.

Thanks for your thoughts.

Adjustment of the nuts at the far end of the spindle to remove excess play is a standard adjustment that should not affect the warranty. It's possible one of the bearing races has seated a bit further into its recess, because it wasn't originally all the way home, or that the adjusters have come loose.

The correct setting depends whether you have ball or roller races on the lathe. probably the former.

See this search of the forum for threads on adjusting Mini Lathe Spindles.

http://www.google.com/search?q=minilathe+spindle+adjustment&sitesearch=model-engineer.co.uk

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Ady1 on 02/05/2023 11:24:35:

Aha.

Vevor Australia

.

Appears to also be offered in the E.U.

**LINK**

https://eur.vevor.com/metal-lathe-c_10121/vevor-mini-metal-lathe-machine-7-x-16-800w-precision-benchtop-power-metal-lathe-150-2500-rpm-continuously-variable-speed-with-3-9-3-jaw-metal-chuck-tool-box-for-processing-precision-parts-p_010746125015

MichaelG.

.

Edit: __ Check the shiny picture of the motor

… I can’t see that having a hollow shaft 

Edited By Michael Gilligan on 03/05/2023 05:09:08

[Michael GilliganParticipant @michaelgilligan61133]

Just found Walmart listing for a BENTISM lathe, which appears to be the same: **LINK**

https://www.walmart.com/ip/BENTISM-Metal-Lathe-Power-Metal-Lathe-7-x16-150-2500-RPM-Continuously-Variable/1957903923?wmlspartner=wlpa&selectedSellerId=101078564

Item is listed but ‘out of stock’

Specification shows Lifespan: 3 Years

… My preconceived notions about machine tools are being trampled under the marching feet of progress !

MichaelG.

[Peter Parkes 1Participant @peterparkes1]

Thanks for all the answers. Much to think about and a few things to say, but not 'till tomorrow im afraid.

Just too busy with work and children right now.

(Howard… It's a 300mm job but I'm only putting pressure on the chuck itself. And very little force).

Cheers.

[not done it yetParticipant @notdoneityet]

I’ve resisted so far but here is my comment, now.

It is vevor, so what do you expect?

Like ban good, vevor sell a lot of low specification products – likely some (or a lot) that are rejected by suppliers of better quality kit. Pot luck if the item is up to all specifications expected. Many don’t check them (and they are very likely the ones who say they are perfectly happy with their purchases from this seller.

My view? If you are not able to fix it, don’t buy it if you can’t afford to throw it away.

The likely typical response will be to offer a minimal partial refund. Good luck with anything else.

I have (fairly) recently bought two items with their name on the sticker. Neither worked to the specification and one arrived without a necessary part (which was clearly shown in the sales bumph). I was already aware, of course, that this might be the case and knew that I could probably get around the shortcomings relatively easily, or those shortcomings would not bother me for my particular application.

Buying cheap is not always the best way.

[Ian PParticipant @ianp]

Posted by Michael Gilligan on 03/05/2023 05:49:34:

Just found Walmart listing for a BENTISM lathe, which appears to be the same: **LINK**

Specification shows Lifespan: 3 Years

MichaelG.

I mentioned the limited lifetime earlier in the thread but I think it only refers to the cast iron bed. Maybe like 'Mission Impossible' it then decomposes leaving the owner with and assortment of components lying on the bench

On a more serious note. The headstock casting looks to be a strong rigid structure (even better than the plain spindle version) which is good news, what does not inspire confidence though, is the small diameter of the motor itself. The radial depth available in small overall diameter and a hollow spindle does not leave a lot of room for the stator windings, rotor and magnets so I suspect the motor will be limited as regards torque.

The brushless motor, spindle and the bearings appear to be what would be described as as 'cassette' that installs in the bore of the headstock casting. Given the limited length and diameter available I think the bearings themselves are not going to be taper roller or deep groove types but more likely quite narrow section ballraces, how well they will perform as lathe headstock bearings we will have to wait and see.

Ian P

[Kiwi BlokeParticipant @kiwibloke62605]

Good grief! That's a picture of a gib strip? Clearly, the thing's been thrown together by ignorant minions, employed by crooks and charlatans, and sold by deceitful people (I was going to say something much worse…). Fight to get your money back, and don't waste time on a heap of junk that may have many more problems waiting to reveal themselves!

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Ian P on 03/05/2023 11:01:26:

Posted by Michael Gilligan on 03/05/2023 05:49:34:

Specification shows Lifespan: 3 Years

I mentioned the limited lifetime earlier in the thread …

.

But presumably you have not yet studied the illustration of the motor

MichaelG.

.

Edit: __ There is a downloadable manual on the EU web page … But still no exploded diagram 

Edited By Michael Gilligan on 03/05/2023 13:02:11

[JasonBModerator @jasonb]

I would not worry too much about the photo, Vevor regularly use ones not related to the actual item.

There are a few more examples on the net not just the Aliexpress one I have mentioned and all look to be able to pass a decent size workpiece through the spindle (assumeing images are correct.) some of the the 8×16 lathes also seem to have this direct motor

[Peter Parkes 1Participant @peterparkes1]

I tend to think that if this machine was used 'as is' it probably wouldn't last more than three years. But what fool would just use it as-is? (Probably many).

Yes, I'm thinking about the refund option. But honestly, I'm still thinking about this as a project like "How to (re)Build a Lathe". I knew it would need some serious work when i bought it. It's just too cheap to be well manufactured and built. I was fully intending to do some extensive work on it. To it. I have a vertical 'milling attachment ' for it (and some dovetail cutters) and was going to start with the gib strips. There's plenty of vids on upgrading and repairing mini lathes and i think it would be a Really satisfying project. I know it might take a while, and some money, but those are things im happy to invest as i can.

Im sure there will be people telling me im mad …but that's always been the case. If you All tell me so, ill rethink my approach.

Aside from that, i think the motor is in the box behind the spindle head. As i recall, it hes cogs but not a belt driving the spindle (not the lead screw gearing cogs). Ill double check when i get out of bed.

For now, this is just too frustrating trying to type this on a phone. Ill writmore in about twelve hours or so.

Thanks all.

[Peter Parkes 1Participant @peterparkes1]

I can't find who suggested it, but all play disappears when i mount the dti on the headstock (very tight fit, though).

My apologies if I've wasted anyone's time. At least a valuable lesson has been learned.

I'm going to unscrew the cover plate from the back of the (apperent) motor box and satisfy all questions about where the motor actually is. There are no evident gears driving the spindle, so we'll see if that's all internal or if its a spindle motor. Back in a while.

Thanks again, all.

[Peter Parkes 1Participant @peterparkes1]

I can't find who suggested it, but all play disappears when i mount the dti on the headstock (very tight fit, though).

My apologies if I've wasted anyone's time. At least a valuable lesson has been learned.

I'm going to unscrew the cover plate from the back of the (apperent) motor box and satisfy all questions about where the motor actually is. There are no evident gears driving the spindle, so we'll see if that's all internal or if its a spindle motor. Back in a while.

Thanks again, all.

[peak4Participant @peak4]

Posted by Peter Parkes 1 on 04/05/2023 01:03:15:

I can't find who suggested it, but all play disappears when i mount the dti on the headstock (very tight fit, though).

………………………

Thanks again, all.

It might be an idea to post some photos of where you are placing the DTI and where is shows movement.

Bill

[Peter Parkes 1Participant @peterparkes1]

Yeah, I'll take a pic, Bill. Basically, though, it was showing movement when the dti was on the base-tray (which I thought was stable). Evidently there is significant movement when placed there so I have learned to not trust my assumptions about the stability of things and to always use the most solid mount for a dti, then check it is good.

I feel like a bit of a fool but I guess we all do stupid things when we are starting out.

Incidentally (for anyone interested) the motor is definitely mounted IN the spindle housing, around the spindle. Much like the photo posted yesterday of one from Ali.

[Chris MateParticipant @chrismate31303]

Make something, and see where it goes to your liking. Then try to figure out what went wrong where and why. As a bonus you gain experience.

[Robert Atkinson 2Participant @robertatkinson2]

A practical measurement is with the DTI on the tool post. It's movement between tool and workpiece that matters.

B.T.W this happens a lot in electronics. Peope think any old but of bare metal is OK to use as a "ground" refrence for measurements……

[Author]

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