Hello:

I have read this forum for a while.

I heard someone saying that a newbie would better to start with a lathe. Well, without real experience, I just feel that lathe has sompler operation than a mill.

Is it a somehow "must" to start from lathe? because even if someone starts with a mill, then he will inevitably find that he still need a lathe sooner or later?

Also, I do not read much CNC conversion about a lathe, most guys talking about CNC conversion of a mill..... Does that mean CNC a lathe is something not so interesting or not so rewarding?

I am eager to jump in some machining while building my bench now.

thanks

Programming a CNC mill in general is easier than programing a lathe. On a CNC lathe the approach angle and cutting direction angle and leadin and leadout angle can be very important. Sometimes a groove or concave area is cut with a knotching tool in the X axis direction. Surface finish and lathe tooling shapes can have a big effect on accuracy. Tool shape compensation can be complicated.
..........Another thing is long curly chips can get wrapped around the parts depending on material being cut. With all the different types and shapes of carbide inserts tooling getting chips to break up into smaller pieces is easier.
I have also used a pulsating or adjustable feed rate to beak up long chips. Cutting 1mm at 250mm/minute and then cutting 0.1mm at 10mm/ minute will usually breakup long chips. Not all CAD CAM programs will program a pulsating feed rate. Sometimes this has to be manually done. Usually CNC on a lathe is more time consuming to program than a CNC mill in my opinion.

I started with manual tools first. Manual mill, then lathe. It is much easier to grasp the different concepts this way, or at least it was for me.
I then build a cnc router, mill and converted the manual lathe. Finally I buildt another cnc lathe from scratch.
Still haven't mastered programming the lathe using Cam, but do most of my parts witting the Gcode myself. This is much easier to do on a lathe than a mill.

The router and mill are pretty similar in movement and are easy to use with Cam.

I know ultimately the lathe will get easier once I start using my Turn Cam, but just haven't had the time or need to learn that part yet.

If you have used mills and lathes in the past, then cnc isn't that much different. There will be some learning curves, but if I can do it, you can too. ;)

So far as programming goes, lathe might appear more straightforward, because a typical part profile is not all that difficult to lay out and write the code for. If you use the roughing cycles on a lathe, it gets really simple to write, because then you need not come up with all the bulk stock removal paths.

Personally, I began with cnc lathe because that was what I had application for first. Of course, I have a general job and repair shop, so you basically can't do anything without having a lathe, because almost all repair work involves things that rotate :D Of course, I had many years experience with several different lathes before I touched cnc. So I had (have) a healthy respect for the dangers of incorrect lathe operation.

In my mind, a lathe crash is a serious matter, where a tool, chuck, and/or workpiece could be wrecked in a few milliseconds, and the danger to personnel nearby is greater. There is nothing 'anthropomorphically friendly' about running a lathe. So you need to be a patient personality, willing to take time to plod through the setup and test running of the program, even the ones you just know are correct ;)

Newbies have more difficulty getting a good surface finish on lathe parts, because tool selection and cutting speed and feed are all critical. Compare to a mill, where the condition of the tool is pretty well going to determine the finish on the part, and when it is not performing, you just put in another one.

Lathe work, at least what I have done, has less room for error than milling work. There are typically some very important diameters to be maintained, and getting those to come out consistently requires perserverance and attention to every detail. A man who has run a manual lathe for a few years will know basically what he wants to try to do, and how to do it quickly and safely.

hello:

it is very interesting to read your posts. Do you guys do the G-code programming by yourself? I am a software engineer, but I am not feeling that it will be very attractive to me if I have to program by myself. My humble question is: why do not you use a program to directly translate your CAD work to G-code?

Or did I miss something along my way of reading? looking forward to hearing back from you ;)

Mostly, I use CAM :D I never was much of a fan of plugging through nc programming the hard way, in fact, programming was my incentive to buy my first computer.

However, if you rely on CAM and don't thoroughly understand the effects of editing your nc code at the machine, you could limit or endanger yourself. I've got quite a few programs 'in stock', so fairly often, I'll find something similar to the current part, and just edit a few lines to make a quick run on a different lathe part. Or, I might wish to edit out any superfluous movements from a CAM generated program, but I do this carefully, and read the program with complete understanding of what I am looking at, and can judge whether it is safe to run.

So if you don't do some manual programming, it is difficult to get that intimately acquainted with what is happening on the machine. Its like you watching a baseball player swing a bat, versus stepping up to the plate and swinging it yourself. :D

For me it was the fact that I wanted to learn about Gcode, coupled with the need to get some very basic parts turned. All my parts only use 3 tools. None require a tool change per part. I am using gang tooling and a Quick change tool post at the home position. I turn about 9 or 10 parts for my product. All pretty basic turnings, so that part was easy.
I stole some of my peck drilling cycles from my mill and just adjusted them for use on the lathe.

My tooling offsets and the fact that I didn't yet need to learn my cam are the reasons I haven't done so yet.
The machines were built strictly for production, however they also will have a hobby use as time arises. Thats when I'll need to get familiar with my cam, offsets etc.

Once you learn just basic Gcode, it is extremely easy to simply jog the machine and log the positions you need for basic turnings. Mach 3 even has program in it that does just this. It's called "Teach".

It took me all of about an hour to get enough Gcode under my belt to be able to use it for my turned parts.

ok, guys, I know your rationales for G-coding by yourself. Seems I need to follow too, I do not want to blindly run my machine if there is any potential risks :(. While this is a little bit of violating of my desire to do some strict manual work instead coding in front of a compute, but seems I have to go back to my PC ;) thanks a lot!

Hello:

I have read this forum for a while.

I heard someone saying that a newbie would better to start with a lathe. Well, without real experience, I just feel that lathe has sompler operation than a mill.

Is it a somehow "must" to start from lathe? because even if someone starts with a mill, then he will inevitably find that he still need a lathe sooner or later?

Also, I do not read much CNC conversion about a lathe, most guys talking about CNC conversion of a mill..... Does that mean CNC a lathe is something not so interesting or not so rewarding?

I am eager to jump in some machining while building my bench now.

thanks You have the option of getting an "all in one", I'm sure that would be cheaper than a mill and a lathe, you also have the option of first buying a mill then later buying an indexer with tailstock which you bolt to your mills table which can be used as a lathe. That's the route I plan on taking.

Is it a somehow "must" to start from lathe?
For me the question when buying a tool is "what do you need to do?"

I like to build mechanical things and this often means cutting holes . A drill press is pretty good at making holes but a mill helps put holes where they belong. CNC a mill and it can cut holes in all kinds of shapes, sometimes even the shape you intended :)

Hacksaws are miserable devices so a bandsaw was #2 on my list.

Lathes are good at cutting round shapes but not good for square shapes. #3 on my list and a work in progress.

These choices were based on the tools I needed. Your needs may be different. Don't sweat the programming/operation. Learn as you go and be careful.

because even if someone starts with a mill, then he will inevitably find that he still need a lathe sooner or later?
imho, yes.