[acondit]

I currently have a HF12x36 (33274) and a Grizzly 9x20 (G4000). I am reluctant to CNC the HF because of all the gear drive mechanisms involved. I am thinking about some of the same issues with regard to the Grizzly 9x20 the half gearbox. Additionally, since I may have to begin downsizing my shop I am thinking about selling both of the lathes that I currently own and replacing them with a smaller CNC lathe or possibly two.

It seems silly to buy an expensive lathe with a lot of features (like a gearbox) to CNC. So I am thinking about one or possibly two of the following lathes:

(1) Grizzly 7x12 (G8688)
(2) Microlux 7x14 (82710)
(3) HarborFreight 8x12 (44859)
(4) LatheMaster 8x14 (CQ6120x320)
(5) LatheMaster 9x30 (HD250x750)

Questions:

Other than the obvious concerns of weight, mass and price, which of numbers 1,2,3 and 4 would you choose and why?
Has anyone had the opportunity to do a firsthand physical comparison of both the HF8x12 and the LM8x14? What are the differences between them other than accessories?
If I bought #5 I believe that it would probably be in addition to one of the first four, so, would you keep one lathe manual and CNC one or would you CNC both?

Thanks,
Alan

[RotarySMP]

Given that space is not a premium concern to you, I would not (again) CNC a 7x lathe.

Since you already have the 9x20 and they are cheap, just CNC that. The gearbox which you will put ina box in the corner of the garage is probably only worth about 80 Rinimbi.

Why sell the 12X lathe? You can never have a big enough lathe!

[acondit]

Mark,

We are looking at retirement and moving into a smaller place where space will be at a premium. Also we are looking at moving to a different city and the cost and hassle of moving a 1000 pound lathe is not cheap.

Alan

[Chris D]

I am currently gathering parts for a 9 x 20 conversion to CNC. Your right about the gear train on the 9 x 20's - the questions stands "Could it be made any worse?"

However, through the CNC conversion, just about everything will be gone from my machine. The bed, carriage, cross slide, headstock, and tail stock will be kept, the rest will be made into a boat anchor.

I already have mine converted to a DC spindle drive. I will be using Gecko 320s, Servos, and ball screws for motion. So, as you can see, not much left of the original machine.

Chris

[RTP_Burnsville]

What about a model similar to the Grizzly G0516? It is the model I have been thinking about as a first lathe.

Robert

[acondit]

Robert,

Positives:
I like some of the specs on it (9.75 swing, 21" between centers on the lathe). It comes with 5" 3-jaw and 4-jaw chucks).

Negatives:
I have not heard many positive things about 3 in 1 machines in general.
It seems to have the same poor design on the compound mount as the 9x20.
The mill at the back seems to make that addition of a DRO more difficult.
The fixed position of the mill head in relation to the lathe head makes it less useful as a 4-axis machine.
The size of the milling table attachment to the crossfeed is pretty small even in relation to the minimill.

Plus I already have a RF30 Mill-Drill and a HF Minimill (both R8).

Alan

What about a model similar to the Grizzly G0516? It is the model I have been thinking about as a first lathe.

Robert

[RTP_Burnsville]

Robert,

Positives:
I like some of the specs on it (9.75 swing, 21" between centers on the lathe). It comes with 5" 3-jaw and 4-jaw chucks).

Negatives:
I have not heard many positive things about 3 in 1 machines in general.
It seems to have the same poor design on the compound mount as the 9x20.
The mill at the back seems to make that addition of a DRO more difficult.
The fixed position of the mill head in relation to the lathe head makes it less useful as a 4-axis machine.
The size of the milling table attachment to the crossfeed is pretty small even in relation to the minimill.

Plus I already have a RF30 Mill-Drill and a HF Minimill (both R8).

Alan

Thanks for the response... A couple additional comments.

The mill head does not need to be attached and LMS sells a matching base/table to turn it into a X2 mill ($200).

LMS also has a replacement spindle if one would rather have R8 tooling ($50).

There are a few other places (PennTool) that offer a similar lathe without the mill head but the price is close to the same. Being you have a mill I see your point.

The larger swing and the extra chucks are a nice feature though.

[RotarySMP]

I have been looking at that G0516 also. The leadscrew cover is one less thing to make that you really need on a CNC. Can you get a T-slotted cross slide for it? Get a three phase motor and a VFD and it would be sweet. Still not worth trading in the machines you have though.

[acondit]

Chris,

I have never been totally happy with the 9x20 in terms of quality of cut. (But until recently I hadn't been happy with my 12x36 or my mill. I spent some time tuning both of them and am now getting great finish cuts.)

So, maybe I need to spend some time tuning the 9x20 and see if I can improve the quality of its cuts and get rid of the chatter.

Alan

I am currently gathering parts for a 9 x 20 conversion to CNC. Your right about the gear train on the 9 x 20's - the questions stands "Could it be made any worse?"

However, through the CNC conversion, just about everything will be gone from my machine. The bed, carriage, cross slide, headstock, and tail stock will be kept, the rest will be made into a boat anchor.

I already have mine converted to a DC spindle drive. I will be using Gecko 320s, Servos, and ball screws for motion. So, as you can see, not much left of the original machine.

Chris

[acondit]

Mark,

I would not (again) CNC a 7x lathe.

I know that space was a big consideration for you in deciding upon a 7x lathe. However, within its size limitations, how do you feel about the performance of the cnc'd 7x lathe?

If the 7x lathe had a more powerful motor, would that solve a number of the issues? If so, would it be feasible to increase the power of a 7x lathe with a treadmill motor to increase its cutting power?

Would the 8x14 be enough larger to satisfy 90% of the reasons behind your statement about not CNC'ing a 7x again?

I know the feeling that "one can never have a big enough lathe", but I have done jobs that were actually less scary on a smaller lathe (turning very small parts up next to a big chuck).

Thanks,
Alan

[phantomcow2]

I would keep the 9x20.
but for the record, the 7x12 I have is a great little lathe. I have been able to keep my work within .0005" if I pay attention to accuracy. Most of the stuff i do is not critical with measurements, so i dont bother with that. The motor on my Homier is labeled as 400w and 4/5HP. I can stop it with my hand at the lowest possible speed which i think is 30-40RPM. After 50 or so torque jumps up

[acondit]

Phantomcow2,

Two of the three people suggesting that I keep the 9x20 don't have one. I think the idea of the 9x20 may actually be more appealing than the fact of the machine.

I had basically considered and rejected the 9x20 as the CNC option for a variety of reasons. Most of the things I do are up close to the chuck; the 4-jaw that came with the G4000 is not something that I want to deal with for a CNC machine; the crossfeed support needs to be modified to even think about CNC; and I can probably sell the 9x20 configured as it is for almost enough to buy one of the smaller machines.

If I need a machine longer than 14", I may well need the 9x30. Most of the things that I have turned, that would have been too long for an 8x14, were too long for a 9x20 (hence the 12x36). There is no way that I can justify having both a 9x20 and a 9x30.

I have only seen one 9x20 configured for CNC and that in and of itself may say something (I am not sure what?).

I may reconsider keeping the 9x20, but what I want to find out if any of the other smaller options that I listed present a better option than the 9x20.

Alan

I would keep the 9x20.
but for the record, the 7x12 I have is a great little lathe. I have been able to keep my work within .0005" if I pay attention to accuracy. Most of the stuff i do is not critical with measurements, so i dont bother with that. The motor on my Homier is labeled as 400w and 4/5HP. I can stop it with my hand at the lowest possible speed which i think is 30-40RPM. After 50 or so torque jumps up

[phantomcow2]

If you do small things, then i can highly recommend the mini lathe.
Overall its a good system, thick gib strips, functioning power feed with threading ability left and right hand. I dont think Sherlines or Taig lathes can thread without add ons.
The 7x12 I have has been sufficient most of the time for my needs. Only once have I neded one more inch, so you might be better off going with the 7x14. I plan to convert to CNC at some point.
Its understandable not wanting to turn small things on a large lathe, i do the same. At my school we have got a 13x48, i rarely use it and prefer my mini. So i think that will do if thats the route you want to take

[acondit]

Phantomcow2,

Thanks for that input, that is the kind of information that I am looking for.

Now if I could get Mark (RotarySMP) to tell a little about how he feels he has tortured his 7x CNC machine and the end results (good or bad), Balsaman to give some feedback on his HF 8x12 (14?) and CNCadmin to give some more feedback on his Lathemaster 8x14 this might become a useful thread for people, like me, thinking about which machine to CNC.

Has anyone cnc'd a MicroMark MicroLux 7x14? It supposedly has a slightly more powerful motor and the headstock is 1" longer than the other 7x10's and 7x12's, not to mention that it comes with a cam release tailstock. I wonder if that motor makes a significant difference in its cutting ability?

I would even appreciate "Chris D" commenting on his 9x20 CNC conversion when it's done.

Thanks to all who have contributed so far.

Alan

[Chris D]

Phantomcow2,

Thanks for that input, that is the kind of information that I am looking for.

Now if I could get Mark (RotarySMP) to tell a little about how he feels he has tortured his 7x CNC machine and the end results (good or bad), Balsaman to give some feedback on his HF 8x12 (14?) and CNCadmin to give some more feedback on his Lathemaster 8x14 this might become a useful thread for people, like me, thinking about which machine to CNC.

Has anyone cnc'd a MicroMark MicroLux 7x14? It supposedly has a slightly more powerful motor and the headstock is 1" longer than the other 7x10's and 7x12's, not to mention that it comes with a cam release tailstock. I wonder if that motor makes a significant difference in its cutting ability?

I would even appreciate "Chris D" commenting on his 9x20 CNC conversion when it's done.

Thanks to all who have contributed so far.

Alan

Somtimes you just have to slap yourself on the forehead and say "wake up!". I completely forgot about this version of the 9 x 20 lathes that were converted to CNC. Emco Maier company of Austria, who were the original designers of the 9 x 20 lathes sells CNC versions!

I was consulting as a CNC instructor at a local company for about 6 years, we had 3 of them in the classroom - they are called PC Turn 50 machines.

It has been about 6 years since I have been there, but this much I remember....


It had a 6 station turret on it - very weak design - too heavy of a cut and the "Shot pin" would release and allow the turret to rotate.

The cut quality was pretty good in aluminum - keep in mind, these are Austrian built machines.

The control they used was a psuedo Fanuc control (you could also get a psuedo Siemens control with them). The control was okay, far from good.

The maximum traverse speed was 29 or 30 IPM.

It used small ball screws - don't know the size of the X axis screw, but seem to think the Z axis screw was about 1/2" diameter. It was mounted on the front of the machine as opposed to the back like one of the retrofitters has done.

It used small stepper motors - I believe they would have been size 23 motors.

They would not cut steel at all unless the cut depth was .020" or so. My 9 x 20 cuts steel MUCH better. It did a pretty decent job of cutting aluminum.

The accuracy of those machines were a bit questionable. When I gave the students an assignement, I expected to get a part back within tolerance (+- .003") Seldom was the case of a student blaming the machine for out of tolerance work, however, anything closer would have been very tough.

I don't recall the machines (steppers) missing steps ever - that is the strange thing.

As far as I know, those machines are still running fine though.

Chris

[acondit]

Chris,

You are right about Emco-Maier producing a small lathe that was the predecessor of the 9x20. Chris Bannister (member of the 9x20 group) from Melbourne, Australia had one (an 8x18 IIRC). I think the Austrian machine was probably better designed and surely better executed than the 9x20. I looked at one years ago. Chris B. used to argue that the Chinese copied all of its flaws and few of its good features (I'm paraphrasing but you get the idea).

I knew that Emco had done a little 5x12 CNC machine but I didn't remember the 8x18 being available CNC (that doesn't mean it wasn't).

Having used a D-3 chuck mount on my larger lathe I am less enamored with the threaded chuck mount on the 9x20. I understand that the Emco-Maier had a sort of modified DIN taper for its chuck mount rather than the sort of straight register of the 7x10, 7x12, 7x14, 8x14 lineage use for chuck mounting. The taper mount would seem to provide more consistent centering alignment when removing and replacing a chuck. Though, it is probably easier for a beginner to turn the straight register than to get a taper set properly.

Alan

[phantomcow2]

It looks like the Lathemaster and the 8x12 do not have a variable speed motor, so your limited greatly to what your spindle speeds can be. THat is something that sets the mini lathe apart, a variable DC motor. The lack of htis does not seem to bother some people, but it drives me nuts if i odnt have it.

[acondit]

Phantomcow2,

You are right, they don't come with variable speed motors and neither does the 9x20. I have already purchased a KBIC-125 DC controller and am looking to decide what motor I want to buy (and what lathe I want to put it on).

Several people have replaced the standard AC motor on the 9x20 with a variable speed DC setup. Alan Trest (stickman4) says on his website that he is planning to do that to his 8x14. Has anyone done that to any of the minilathes to get more power out of them? Are they strong enough to be able to use more power?

Alan

It looks like the Lathemaster and the 8x12 do not have a variable speed motor, so your limited greatly to what your spindle speeds can be. THat is something that sets the mini lathe apart, a variable DC motor. The lack of htis does not seem to bother some people, but it drives me nuts if i odnt have it.

[phantomcow2]

I would not hesitate to put a more powerful motor on for the mini lathe.
Others may feel different, but i have never found the motor power to be a limiting factor. On mini-lathe.com though, the author says he starts to approach the limits when he uses the 5 jaw chuck with large stock.

[acondit]

Phantomcow2,

Did you mean 5" chuck?

Alan

On mini-lathe.com though, the author says he starts to approach the limits when he uses the 5 jaw chuck with large stock.