# Need Help In Choosing Mini Lathe - 7x14 Vs 8x16



## dakopian

Hi Dear enthusiasts/professionals!

I need your help in choosing a right lathe for my needs.

First of all, shortly about me: firmware engineer. I got some machinist experience in my childhood, that knowledge is 14 years old, so I'm considering myself as a newbie. My hobbies include RC models, model rockets. After reaching some point in that, I realized that my ideas are limited by capabilities of my tools. To go to the next level I need a bench top lathe. 
It's unlikely I will process things larger than, say, 4" x 5", so, seems to, 7x14 lathe would have enough size. What I really need is accuracy - 0.0005" is pretty desirable. I understand it's unlikely I get that accuracy right out the box, but I'm very ok with doing some adjustments/improvements by myself (as long as heavy machinery is not needed). Most used materials are aluminum and delrin. The budget is something about $1000 (there is no way to get approval from my wife for any higher  ). And, yes - I'm going to operate the lathe in my apartment, so noise level matters.


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## dakopian

After doing some research, I'm considering next candidates:

1) Grizzly G0765 (7 x 14) - seems to be a classic Chinese lathe from the same factory as Big Dog lathe. A lot of positive reviews on YouTube and price you cannot beat - $674 with delivery. If I go with this lathe, I would spend almost $400 on accessories/mods and finally, I would get a decent lathe (probably).

2) Grizzly G0768 (8 x 16) - heavier and cooler lathe made of metal, no plastic gears. If I go with that, it will take a long time to get an approval from my Boss for any additional spendings on accessories. Main questions: is this lathe more rigid than previous one? Is it more accurate? Does it worth extra bucks?

3) Sieg C3 (7 x 14) from LMS. Very similar to option #1, but weaker (350W vs 550W). Maybe it's much better quality?

4) HiTorque 5100 (7 x 16) from LMS. Seems to be one of the best 7x lathes. Cost about the same as #2, but it's still 7x lathe with the same origin as #1 and #3. Only one difference is BLDC motor. As I understand, all the machines listed above have some electronic control circuit which maintains RPM under various load. It's unlikely I will be processing large diameter stock very often and I'm not lazy to switch the Lo-Hi lever. But if this lathe gives me the best accuracy, I will opt it out.

All the internet forums are carefully studied, mini-lathe.com is being my homepage for a month 

My mind is about to blow up, so I really hope for any help/suggestions - that would be much appreciated!

Thank you,

Dmitrii


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## wrmiller

Had a 7x16 from Micro Mark that is basically the same machine as the LMS. The BLDC motors are better at maintaining a constant speed than the brushed DC motors.

Given your description of what you intend the machine for, you are not going to stress any of the lathes you describe. You will however, have to basically take the thing apart and clean, measure, deburr, stone, possibly file, make new gibs, etc. to get the accuracy you are looking for. The small Chinese machines (even my LMS mini-mill) are basically kits that you tweak to get the accuracy and functionality you want. Not much help, sorry.


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## kd4gij

I usually say get the biggest lathe you can afford and have room for. But it sounds like you are cramped for space. And tooling is as important as the lathe.  You just need to find a way to get the better half to thing it is here idea.     One thing you need to look at is what is the swing over the cross slide. A 7" lathe will swing 7" over bed but you can't turn the od.  I haven't run a 7" or 8" lathe so I can't help there.


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## dakopian

wrmiller19, kd4gij - thank you guys for participation!

Currently, I feel like these are 2 border cases:
1) Buy the cheapest one 7x14 and invest time and bucks in improvements.
  Pros:
    - Lots of online materials/reviews. Well known machines.
    - Less noise (because plastic gears and power feed disengagement system).  
    - Due to low initial price, lots of extra money to invest in accessories which are right for the work I intended to do.
  Cons:
    - Number of major modifications needed (tapered bearings, lapping) to achieve desired level of accuracy.
    - Limited rigidity which is difficult to overcome.

2) Invest the whole budget in a larger 8x16 machine.
  Pros:
    - Looks sturdier, more operational space (which is not significant factor for me, but who knows).
    - All the gears are made of metal.
    - Tapered bearings from the factory.
    - 4 jaw independent chuck in the box.
    - At the first glance and from the single existing YouTube review, good overall finish and quality.
  Cons:
    - Potentially more noise due to metal gears and power feed design (all the gears seem to be engaged at all the times).
    - Very limited number of reviews/feedback.
    - Belt manipulations needed to switch between Lo-Hi spindle range (although, 'Lo' configuration will be used 99% of the time).

I've seen some feedback from the people who own 7x series, like "If I could make that choice again, I'd better start from, at least, 8x series".

Also, I found the next note in G0768 manual: "Reducing backlash to less than 0.002" is impractical and can lead to accelerated wear in leadscrew and other components. Avoid temptation to overtighten leadscrew nut or set screw while adjusting. ".
Does that mean the accuracy better than 0.002" is not achievable?

Sorry for too many letters


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## brav65

dakopian said:


> wrmiller19, kd4gij - thank you guys for participation!
> 
> Currently, I feel like these are 2 border cases:
> 1) Buy the cheapest one 7x14 and invest time and bucks in improvements.
> Pros:
> - Lots of online materials/reviews. Well known machines.
> - Less noise (because plastic gears and power feed disengagement system).
> - Due to low initial price, lots of extra money to invest in accessories which are right for the work I intended to do.
> Cons:
> - Number of major modifications needed (tapered bearings, lapping) to achieve desired level of accuracy.
> - Limited rigidity which is difficult to overcome.
> 
> 2) Invest the whole budget in a larger 8x16 machine.
> Pros:
> - Looks sturdier, more operational space (which is not significant factor for me, but who knows).
> - All the gears are made of metal.
> - Tapered bearings from the factory.
> - 4 jaw independent chuck in the box.
> - At the first glance and from the single existing YouTube review, good overall finish and quality.
> Cons:
> - Potentially more noise due to metal gears and power feed design (all the gears seem to be engaged at all the times).
> - Very limited number of reviews/feedback.
> - Belt manipulations needed to switch between Lo-Hi spindle range (although, 'Lo' configuration will be used 99% of the time).
> 
> I've seen some feedback from the people who own 7x series, like "If I could make that choice again, I'd better start from, at least, 8x series".
> 
> Also, I found the next note in G0768 manual: "Reducing backlash to less than 0.002" is impractical and can lead to accelerated wear in leadscrew and other components. Avoid temptation to overtighten leadscrew nut or set screw while adjusting. ".
> Does that mean the accuracy better than 0.002" is not achievable?
> 
> Sorry for too many letters



I think the tendency as new guys (myself included) is to chase perfection, i.e. extreme accuracy. In reality the accuracy needed for each project is a function of its intended use. I struggle to try and keep the obsession with perfection within reason, in all areas of my life. There are thousands of guys producing unbelievable projects on these mini lathes.


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## JimDawson

dakopian said:


> Does that mean the accuracy better than 0.002" is not achievable?




Not at all.  I think what they are talking about is backlash in the leadscrews.  Once you get down to the 0.002 range, the accuracy is dependent more on the operator skill than the machine.


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## T Bredehoft

That .002 possible error would be in length, not diameter. Is it critical?   Only you know.


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## wrmiller

As Jim said, backlash isn't machine error it's a description of the amount of free rotational movement of a leadscrew within it's mating nut. You WANT some backlash on all of your screws or you will suffer premature wear on the screw and/or nut. I prefer about 5 thou or more on my leadscrews. When moving a cutter or work piece (lathe vs mill) you want to do your movements so that the screw and nut are always loaded. This is where practice and skill have much more impact on a part's final dimensions than the overall tolerance of the machine will. I have built competition guns on aluminum Sherline machines in my past. I cut a titanium compensator on my 7x machine (won't do that again...). I wouldn't recommend these types of work to a beginner, but things like this can be accomplished on these smaller machines.

If you need quiet, I would stay away from the steel gears. Plastic gears and belt drives are SO much quieter.


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## stupoty

I had a 9x20 (cm) lathe as my second lathe, i liked a lot about it and a few things i don't so much. 

I didn't have a quick change gear box on mine so changeing  Feed speeds means fidling with change gear for a few minuits(at least) this causes a user to find sets of speeds that work well and not change so much where as with a feed gear box you can try different feeds very quickly and easily.

Rigidity was always a little bit of an issue, parting off could be problematic.  I realised that the frount gib is only a half gib on mine.

The one i had had a flange mount chuck which was a bit problematic as it had 3 bolts to fit and remove a chuck but the nuts were rediculusly dificult and fidly to use.  A cam lock one would be much easier or a thread mount is also quick.

I got into using centers a lot.

Good hunting 

Stuart


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## Milehimachine

Have you considered the Sherline products?  From your post it seems those would be the perfect ones for your situation, accuracy, noise and space.


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## Sitting on Blocks Racing

I went with the 7x14 Grizzly and love it.   I wanted to go bigger but realized I be spending a ton on tooling. probably what I spend on the lathe itself.   I just couldn't afford both the lathe and to actually get the tooling to use it and start having fun.


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## wrmiller

That's true. I've easily spent 1.5-2 times the machine cost for tooling. Especially if you're just starting out. The good part is you can spread that cost out over time.


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## dakopian

Thank you for the explanation about backlash - I think I got it!

Sherline makes interesting products, I'm pretty sure lots of people are having fun with them. But the machines seem to be very basic and limited. No compound slide( I may be wrong about that), no power feed, and, main restriction is the size - only 3.5" over the bed and 1.88" over the cross-slide. It doesn't sound serious.

I found couple other topics on this forum with basically the same question as mine:
http://www.hobby-machinist.com/threads/first-lathe-g4000-vs-g0768.30044/
http://www.hobby-machinist.com/threads/grizzly-g0768-8-x-16-lathe.36042/
As I understand, both guys went with the larger lathes - 10x22 or so. Unfortunately, it's not an option in my case - I need something I can lift alone or with the help from friend/wife. 8x16 seems to be the largest liftable size. From other hand, big machines (at least affordable ones) are lacking of speed regulator/ power feed reverse. And, if I understand correctly, larger size not necessary means more rigidity. Say, if we increase the swing over the bed from 8" to 10" (25%), we have to increase the bed/headstock rigidity on 25% as well to get, at least, the same overall rigidity (please correct me if I wrong).

So I'm still choosing between the cheapest 7x14 + lots of extras or more expensive, but nice-looking 8x16. I feel like it's time to stop thinking and start doing. Should I toss up a coin?  Tomorrow, hopefully, I will try to make couple cuts on 7x12 lathe. Maybe that will help.


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## Charles Spencer

Well, one weighs 100 lbs and the other weighs 166.  It seems that it wouldn't be too hard to move either one.

Both have an MT3 spindle in the head stock and an MT2 in the tail stock. 

The 8" one has a 4 jaw chuck listed as standard and the 7" one doesn't.

The 7" lathe requires change gears.  Frankly that's never been a deal breaker for me because I don't thread that much.

More feed options on the 8"

The 7" costs $400 less.

The 8" lathe is bigger.

Sound rating is 76 dB for the 7", not given for the 8"

I've almost always bought tooling as I needed it or if it was a really good deal.  You should be able to start with either with about the same initial outlay, except for the 4 jaw chuck.

Two of my favorite hobbies are machining and cooking.  At one time I was overseas and my wife bought a new electric stove.  I think she got the cheapest one available.  We had it for seven years.  After three years I had to replace the oven coil.  Seven years is a very short life time for a stove. 

We replaced it with a stove that cost about $300 more.  The new stove had a flat top, variable sized burners, a convection oven, and various other features I like.

I bought my cooking pans, knives, etc. the same way as I buy tools.  As needed or by jumping on a really good deal.  I have a halfway decent kitchen set up now.

I enjoy my pans, knives, etc. much more now because I like and have confidence in my stove.


I guess I'm saying that I'd probably go for the 8" lathe.  It will most likely be more useful and durable.  My general philosophy for buying anything is to never get either the cheapest or tthe most expensive.


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## dakopian

Thank you everyone for your opinions!

Today one of my colleagues kindly allowed me to play with his grizzly 7x12. I got a lot of positive emotions! None of service/adjustments/modifications were performed on that machine.  I believe, the factory conservation grease is still on the ways. But even in such condition it works great! The lathe is definitely capable to do everything I ever need.
Being that much impressed with 7x12" lathe, I ordered.. 8x16! Why? Because it looks cooler and has 4 jaw chuck. At least, I can play a while and return it back to grizzly if find it doesn't worth extra money comparing with 7x14.

Lathe starter kit with QCTP from LMS is also on it's way 

I see lack of information about 8x16 in internet. Will try to fill the gap! And I expect myself to be more involved in discussions on this forum soon.

Thank you again!


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## mws

I don't think you'll ever regret getting a little bigger machine. Welcome to the fray.  When you start thinking about adding a Palmgren type milling attachment to your cross slide, it'll be time to consider buying a mini-mill.  I'll give you a few years on that.


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## Wheresmywrench?

_Find what will do what you want it to do *THEN* go to the next one larger!_


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## Charles Spencer

mws said:


> I don't think you'll ever regret getting a little bigger machine. Welcome to the fray.  When you start thinking about adding a Palmgren type milling attachment to your cross slide, it'll be time to consider buying a mini-mill.  I'll give you a few years on that.



Hah!  Not more than 24 months and more likely between 5 and 10.


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## Micke S

I have an old Mini Lathe, an EMCO UNIMAT 3. It is quite week but I use it for very small parts. Maybe I'm destroyed by the great cutting force of my 70 year old Örn-lathe 
It cuts T6 aluminium like butter.


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