NUMOBAMS 8x16 (NU-210G) Lathe Review

[Susquatch]

I've seen people discuss bed wear effect, but have not seen much reference quantifying it relative to a cylindrical datum surface.

I understand. And I agree. My own mind tends to be easily lured into chasing such things too. I love rabbit holes......

However, I think the whole subject of lathe head alignment is generally so badly misunderstood by so many others that I prefer to try and keep things simple. It's hard enough to explain the difference between tail stock alignment and head alignment without adding in the effect of saddle and way wear. So I simply didn't mention it. Then again, I didn't mention ambient temperature, machine warm-up, indicator contact angle, cutting force, speed, etc etc etc either.

Of course, omitting things like that then invites criticism from others who know more and don't like to oversimplify. Sometimes you just can't win.

It doesn't stop me from trying to help others where and when I can though. It's the least I can do given all the help others have given me.

Anyway, thanks for clarifying Peter. It is much appreciated.

 

[StevSmar]

@Susquatch , you know modelling a lathe in Fusion 360 and then applying loads to the supports would be a great project for someone learning Fusion…

(I suspect you’d need a one month subscription once everything is modelled up, to do the analysis though)

 

[Susquatch]

@Susquatch , you know modelling a lathe in Fusion 360 and then applying loads to the supports would be a great project for someone learning Fusion…

(I suspect you’d need a one month subscription once everything is modelled up, to do the analysis though)

I think that would be a great idea for someone who has more free time than I do. I'm quite familiar with modelling complicated parts and assemblies. I used Catia before I retired. In my opinion, modelling a lathe would be way too much work for me.

 

[StevSmar]

I think that would be a great idea for someone who has more free time than I do...

It certainly does take an exponential amount of time the more complicated the model is!

I really liked the cardboard model Joe Pieczynski has at about the 3:30 mark of his video:
Lathe Leveling - Waste of Time ????
This was a perfect level of detail for me to visualize what was happening as I experimented.

 

[Susquatch]

It certainly does take an exponential amount of time the more complicated the model is!

I really liked the cardboard model Joe Pieczynski has at about the 3:30 mark of his video:
Lathe Leveling - Waste of Time ????
This was a perfect level of detail for me to visualize what was happening as I experimented.

Unfortunately, I have an overactive imagination. Don't need videos. Lots of things involving beds happen in my mind.....

Something for you to think about..... Imagine what went on in the minds of the people who developed, tuned, and used lathes back in the early days! Those folks were truly gifted.

 

[StevSmar]

…Lots of things involving beds happen in my mind.....

Yes, I know I dream of beds too. Lathe beds, Road beds, Superconductor Electromagnetic beds, garden beds, beds of roses, creating bed-el-em etc. There’s probably other beds to dream of I guess.

Something for you to think about..... Imagine what went on in the minds of the people who developed, tuned, and used lathes back in the early days! Those folks were truly gifted.

I’ve been getting interested in industrial history. How did we get to today. Interesting how there was no widespread need for machining accuracy until until the steam engine (from what I’ve read so far). How did someone work out that rubbing three stones together made them exceptionally flat.

(There is no such thing as an electromagnetic bed that I know of, that was a “this story has been modified for dramatic purposes”, I had to think of some type of bed that was related to Electrical Engineering)

 

[trlvn]

I’ve been getting interested in industrial history. How did we get to today. Interesting how there was no widespread need for machining accuracy until until the steam engine (from what I’ve read so far).

I ran across a book that you might find interesting:

The Perfectionists
How Precision Engineers Created the Modern World
by Simon Winchester, 2018

Very much in the field that you mentioned although I don't recall if it described lapping to create a reference surface. Might have but I don't recall. It was available to borrow from our local library system.

Craig

 

[DavidR8]

I ran across a book that you might find interesting:

The Perfectionists
How Precision Engineers Created the Modern World
by Simon Winchester, 2018

Very much in the field that you mentioned although I don't recall if it described lapping to create a reference surface. Might have but I don't recall. It was available to borrow from our local library system.

Craig

I have read that book and it's excellent!

 

[historicalarms]

Yes, I know I dream of beds too. Lathe beds, Road beds, Superconductor Electromagnetic beds, garden beds, beds of roses, creating bed-el-em etc. There’s probably other beds to dream of I guess.

I’ve been getting interested in industrial history. How did we get to today. Interesting how there was no widespread need for machining accuracy until until the steam engine (from what I’ve read so far). How did someone work out that rubbing three stones together made them exceptionally flat.

(There is no such thing as an electromagnetic bed that I know of, that was a “this story has been modified for dramatic purposes”, I had to think of some type of bed that was related to Electrical Engineering)

Dont know how it was arrived at but I have been very close to a lot of stones that were made flat to fit together 3-4000 yrs ago (Greek Parthenon and a # of other structures over there) but I can tell you it is amazing to see columns of stone from that era that you still couldnt get a cigarette paper between them. the joints between stone sometimes are only visible by very close observation.

 

[DavidR8]

Dont know how it was arrived at but I have been very close to a lot of stones that were made flat to fit together 3-4000 yrs ago (Greek Parthenon and a # of other structures over there) but I can tell you it is amazing to see columns of stone from that era that you still couldnt get a cigarette paper between them. the joints between stone sometimes are only visible by very close observation.

I saw the same thing in Peru at Mayan ruins. Stone blocks the size of small cars fit together with unbelievable precision. The most amazing to me were stone blocks connected together by with keys made of different stone from a different quarry.

 

[StevSmar]

I ran across a book that you might find interesting: The Perfectionists, How Precision Engineers Created the Modern World, by Simon Winchester, 2018…

I REALLY enjoyed that book and it’s what set me down the path of learning about industrial history. I’ve read other books by Simon Winchester and I’ve found them tough going- this one I limited myself to one chapter a day so I could spread the enjoyment.

I should re-read it over the summer. I’ve tried to find books with a similar treatment but have not yet.

 

[opensourcefan]

TRANSACTION CONCLUSION, finally.

I finally got my replacement chuck which was also sudo compensation for all the troubles with this lathe. We agreed on this being sent to me as compensation and then when the time came to ship I got the standard "there's a problem" which I heard before. All of a sudden, someone who claims to ship packages all day long was surprised by the shipping cost for this and wanted money from me to cover some of it. I didn't tolerate that even a little and he eventually shipped it after a back and forth which I will spare you all from.

Also FWIW, I contacted PayPal and they stated that if there was a deliberate attempt at stalling to pass time beyond the 180 day protection that they would open a claim without issues. They were ready to do it but I held off pending receipt of this package, it's a good to know anyway.

This brand seems to be considered the better of the cheap chucks from China. It still required a complete disassembly and a lot of deburring. It actually would barely turn on arrival, it was bad, worse actually than the cheap junk that was installed on the lathe in the first place. However it's build is much more solid and refined compared to the other, which sounds weird to say after the previous sentence. Once deburred and cleaned up it feels excellent. It is consistently running out at .001" which I'm okay with.

 

[Susquatch]

TRANSACTION CONCLUSION, finally.

I finally got my replacement chuck which was also sudo compensation for all the troubles with this lathe. We agreed on this being sent to me as compensation and then when the time came to ship I got the standard "there's a problem" which I heard before. All of a sudden, someone who claims to ship packages all day long was surprised by the shipping cost for this and wanted money from me to cover some of it. I didn't tolerate that even a little and he eventually shipped it after a back and forth which I will spare you all from.

Also FWIW, I contacted PayPal and they stated that if there was a deliberate attempt at stalling to pass time beyond the 180 day protection that they would open a claim without issues. They were ready to do it but I held off pending receipt of this package, it's a good to know anyway.

This brand seems to be considered the better of the cheap chucks from China. It still required a complete disassembly and a lot of deburring. It actually would barely turn on arrival, it was bad, worse actually than the cheap junk that was installed on the lathe in the first place. However it's build is much more solid and refined compared to the other, which sounds weird to say after the previous sentence. Once deburred and cleaned up it feels excellent. It is consistently running out at .001" which I'm okay with.

View attachment 24407

I always marvel at the consistent failure to execute the manual details for something that comes from a country with supposedly low labour costs.

Anyway, glad you are happy with your diamond in the rough. I enjoyed following your journey. Thank you!

 

[StevSmar]

TRANSACTION CONCLUSION, finally.

I finally got my replacement chuck which was also sudo compensation for all the troubles with this lathe.

That’s great you were able to finally complete the transaction. Sounds like you’ve got a better replacement chuck too!

I still really like the colour of your lathe…
(because it reminds me of a model plane I built as a kid, and it’s close to the colour of the second hand kitchen cabinets we had at the cottage (we painted the backsplash in the kitchen the same green out of fondness…))

(My apologies I contributed to taking your thread off topic with the discussion on alignment… we should have taken that to another thread and not polluted your thorough summary of your purchasing experience with an alignment side discussion)

 

[opensourcefan]

GEARBOX REVIEW

Well, the one thing I didn't take apart and I should have sooner. Below you will see pics that are kinda disturbing considering these were intentionally installed on a new lathe touting quality. It shifted fine into the gears but it didn't feel repeatable or solid, now I know why.

As per the Grizzly manual for this lathe model the gears should be lubricated with grease and serviced annually. As you will see in the photos there isn't any grease on the gears just something (don't know what) on the brass shifting fork #341. You will also see some miss-drilled detents on the shaft bracket #306. Due to the position of the detent hole on the knob, the detents in use were the two on the right and the screw head phillips slots. The shaft #311 is disgusting, I don't think I could have done this poor of a job intentionally. The design is bad as well leaving only an 1/8" bearing surface for the shaft to rotate on. There are also a couple miss drilled set screw locators on the shaft for the knob.

All I can say is, wow! Guess I'll be redesigning and making some bits.

 

[Tom O]

Can you check gear engagement with the detents showed it might just be right after all but you would think that it would be in the middle.

 

[opensourcefan]

Can you check gear engagement with the detents showed it might just be right after all but you would think that it would be in the middle.

I did, the left detent wasn't in use. Neutral is the far right detent. I think that bracket came off of another machine or it was a left over part.

 

[PeterT]

That doesn't look like too difficult a part someone could make for you as a fresh blank & you could re-do the detents. @Tom O is right, it may not be equal purely as a result of the mechanism throw itself. But if the position is out & engagement difficult, that blows & must be dealt with. It has the telltale signs of how these machines are made (right up to & including my Taiwan 14x40). They line it up by eye & out comes the hand drill. Also check that maybe either collar has not come loose on its shaft. ie by loosening & shifting maybe there was a better position & now its out of phase.

Just keep telling yourself : its a KIT, I LIKE building KITS!

 

[opensourcefan]

I've already made the replacement bracket modified with a bearing surface. Ran out of parting inserts so it's on the lathe waiting while I stare at the hacksaw

Rebuilt the shaft as well. I'll add the detents once it's all together. I was running without one detent this whole time anyway.

The beauty of having the gearbox is neutral. Less noise, less wear and tear, and more available power.

 

[Susquatch]

while I stare at the hacksaw

So that's what your avatar is all about!