A Machinists Dream

[rook]

Like I said before  - I sell industrial machinery. 

Those cnc lathes are toys that wouldn't last a month in a production facility.  Maybe used in a clean room for prototyping out of plastic, but not metal.

The conversion kit you pointed out is just brackets for the X & Y axis, there are no motors, vf drives, controls, software or ANYTHING that would give you a "CNC" machine

The Harbor Freight, or anything from Harbor Freight for that matter is the cheapest of Chinese products.  I have seen way to many Harbor Freight, Grizzly and MSC machines pilled up in the corner of shops waiting for scrap prices to rise


Rook

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HAN SOLO

[MoonDragn]

Thats the point. Alot of us aren't going to be putting this in a production facility. This is for making ONE saber usually, or maybe a few extra to sell. The quality of the Chinese machines are getting better and better nowadays as their production factories get upgraded. The point though is that it is cheap and can be easily replaced when it wears out.

Those CNC lathes are meant to be used for metal, not plastic. It says so in the text. The conversion kit lists which stepper motor you can buy for the conversion, I believe those motors are around $20 bucks each. http://webtronics.stores.yahoo.net/stmo5.html

Its great you sell industrial machinery, but we're not making a factory here. We're home hobyists with limited room in our workshops. Mini-Lathes would more than adaquately cover my needs.

[rook]

I understand the hobbiest viewpoint.

As for Chinese machines becoming better.....    Um - yeah, they do a very good job of making a very nice tight accurate machine - when it is new.

The big problem is the Chinese Steel.  Thier steel still contains way to much silica, IE; SAND. 

Their steel is not very reliable - it wears at an incredible rate, breaks and chips too easily and just not good for machinery.  Sure - you can make toys and ornamental stuff, but nothing durable.
All the gears in a machine will become loose from wear immediately, bearings lose tightness and any wear surface such as ways get out of true so rapidly that they become worthless within months.

Looks great on the shelf, but after short use.......  you rarely see used ones as they are all trashed.  Be very wary of used Chinese machines on ebay.

I know many a dealer that took on a new line of Chinese machines because they are just sooo xxx inexpensive, then end up out of business or dropping the line when the machines fell apart and the manufacture wouldn't stand by thier warranties or stock parts.  Quite a few are fighting of lawsuits from buyers right now.

Rook

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HAN SOLO

[MoonDragn]

Yeah I know what you are saying. I happen to be Chinese. I know their steel is not very reliable. But it will get better. They are constantly improving and their steel is much better now than it was 2 years ago. The stuff is the no frills version of a home workshop. As long as you don't plan on mass producing stuff, it works great for a few drilled holes here and there and a few lathed pieces.

Luckily you can get replacement parts for some of their stuff from real good companies because alot of times the Chinese machines are knockoffs  of the real thing.

Take the metal throated sheer from China for example. It uses blades the same size as the beverly shear so you can easily just buy the replacement blades from beverly to use on it.

I am considering buying a small lathe for hobby use. Which would you recomend if not from harbor freight? I don't really understand any of these "features" so I don't know which lathe is good and which isn't.

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HAN SOLO

[Acerocket]

The hardest part of CNC is understanding how to write the G-code to do the work for you. There are some manufacturing software out there that can turn drawings from Autocad into g-code to do the work for you. I'm not sure how expensive that would be as I have not looked into it. However, for the simple stuff, once you figure it out, you can make and repeat stuff faster than doing it by hand. Especially if it doesn't require changing tools. Ultimately changing tools is what makes those super machines so cool, you can't do that without paying the price.

There is NO software that will convert an AutoCAD drawing into G-code.  You, the programmer, will have to program the part.  I use a 12,000 dollar program to  do my programming and there is a lot of hands on work involved.  Granted, I do not have to physically type in the G-code (unless I choose to hand edit the programmed code), but I have to tell the program exactly what I want/need and then have to verify it before the program can generate the code.  I run into people all the time that think all I have to do is open a file, push a button and the part is magically programmed and ready for machining.   What's worse is the people who think all they need is a picture of the part that I can scan into the computer and push a button or two and it comes out of the machine all perfect.  

Now, as far as tool changers for a lathe, how about this one:

It's got a dual turret with 23 tools capability.

[MoonDragn]

So you are saying the programs on this page http://www.rotordesign.com/servolite/body_dxf_to_gcode.html

don't work?

[Acerocket]

Not saying they won't work.  But you are not going to open a dxf file, press the ENTER key and have a G-code program saved to your desktop.  It's just not that easy.  With a very simple program like that, you can probably enter data for a single tool/material once and it will come close to automatically programming your other parts.  But you will still need to enter the data for the computer to crunch the numbers and spit out the code the first time.  At the very least you will need to tell the computer the diameter of the tool, a height offset, and how fast the tool can move in feed and rapid.  You will need to know the material properties also so you can figure out the speeds and feeds you need.  Some programs have built in calculators for these, but these can vary dramatically depending on your machine.  

I have an engraving program that is similar to what you are asking about.  I can import a 2D dxf file and then with a few keystrokes I can generate a G-code file that works perfect with my mill.  But it only works if I use a the engraving tool I first programmed, aluminum material and the exact same XYZ datum point for the corner of the material.  If I change a single parameter, I will have to enter new data in the tool library.

My CAM program has a 2 axis lathe module and a 4 axis mill module.  I have 28 tools programmed for the lathe, 67 tools programmed for the mill, data for 14 materials, and several pages of notes for speeds and feeds that work best for my equipment.  Even programming an easy part requires entering a lot of data in each operation wizard.  You really have to ask yourself if a 200 dollar program will work, then why would someone (actually, a lot of someones) buy CAM programs that cost upwards of 30,000 dollars?  Yes, they add more features, but they do not necessarily make programming easier.

I have used the cheap Chinese lathe and mills before and knowing their accuracy first hand, I would never go that route to CNC.  You are more than welcome to buy one yourself and add a CNC retrofit kit and buy one of those dxf to G-code generating programs if you want to get into CNC machining.  I wish you luck.  But don't believe everything you may have heard about just a few keystokes and your part is ready - it does not happen like that.

[MoonDragn]

Well I happen to be a programmer, and I understand how something like this would work. I could probably come up with some kind of algorithm to work with a wide variety of tools, materials etc. It is all just a matter of a few variables. Advanced calculus.

Either way. So which lathe do you recomend for making simple lightsaber parts if not those chinese lathes?

[QUI-GON JINN]

Let's be sure to keep this discussion civil,  shall we?  I'd hate to have to lock it and throw it away....

[Acerocket]

Let's be sure to keep this discussion civil,  shall we?  I'd hate to have to lock it and throw it away....

I did not think I was being uncivil.  I was just trying to pass on some information to MoonDragon so that he can make some educated choices about what he wants to accomplish.  I have known a few people who thought they could become garage CNC machinists only to get frustrated and sell their equipment.

I made this saber entirely on a Chinese 3-in-1 mill/lathe without CNC.   So I do have some experience with the quality of work you can get from a Chinese machine.



A low budget off-shore machine is a great way for the average Joe to get into machining.  They can be made to produce nice work if you spend the time to learn their quirks.  But, they are not always the best candidate for a CNC conversion.   It all comes down to what you want to do.  If all you ever plan on doing is turning a few sabers for you and your friends, then a Chinese conversion might be the best way to go.  If you want to start a little garage business making sabers, it would be wise to look into a machine with a little more unph.  But the machine is only part of the equation.  If you want to go CNC, you will have to have a G-code file to run on it to cut your part.  In the old days, all G-code was hand written.  But now there are thousands of programs that can write G-code - from the simple to use to the unbelievable complicated 6+ axis programs.  But the common denominator of all the programs is that they still take some user input to generate the code - the more complex the program, the more input will be needed.  I was just trying to impress upon people who read this thread that it is not as simple as drawing in - G-code out.

I never meant to imply I was angry or mad at MoonDragon.  I just want to arm him with the facts.  It would be a shame if he invested his money into a machine only to be discouraged, sell it and quit the hobby over it.  If MoonDragon wishes to PM privately, I will be happy to offer my suggestions in helping him choose a machine.

[MoonDragn]

Its ok, I did not take your comments as uncivil. I really appreciated the advice from someone who's been through it already. I was on the fence about the subject and you've convinced me to not take that road for now. I PMed you and hope to get some advice on which lathe I should get. 

I'm not planning on starting a cottage industry in sabers though. I make close to $70/hr at my job. It would not be worth it to quit my job and make sabers. I'm only doing it as a hobby and I would use the lathe for other metal or wood working projects. I am not looking to turn out mass production of sabers. Just a hobby to fiddle around with my imagination.

[rook]

If I was going to get a lathe for my home shop, I'd get an EMCO  (Note: - this is eMco, not eNco)
They make very nice machines, German engineered and Quaility
http://www.emco.at

They also have small CNC prototyping and CNC's that run from PC's.  Unfortunately, they are expensive.  But you get what you pay for.

If cost was an issue - I'd get an Acer/Jet  (pretty sure they are made in the same plant and just rebadged)
http://www.acergroup.com/

Thier larger machines seem to survive in industry with fair use, heavy use does destroy them, but you may be able to find one on Craigslist in fairly good condition.

Rook

[MoonDragn]

I don't have alot of room in my workroom. How about a mini-lathe?

What do you think of this? http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=82710

Or this? http://www.toolsnow.com/browse.cfm/4,876.htm

Both are made in China also from the same factory that makes the Harbor freight ones. In fact, some Grizzly, Micro-Mark, Homier Mobile Merchants, and ToolsNow Lathes are all made from the same place.

Btw, the cheaper Jet Lathes are made in China also..

Emcos are made in Australia and seems that the ones for sale on Ebay are no longer in production. Support and tools may be hard to come by.

The cheapest Acer Lathe I can find on ebay is $7k

I'm reading that the Taiwanese lathes are better than the Chinese lathes if I want to go with thrifty. What do you think of them?

[Lord Dracus]

  That CNC Machine is pretty cool !!! :)

[rook]

I can't comment on those teenie lathes as I've never come across them.

As for Jet being Chinese - yeah, I am aware of that, but they do seem to hold up a little better than other makes.

For the cost of the little lathes - it's not like you could lose much,  I'd go with the micro-lux of the two.

ya know - because they use Metal Gears   ;)

Rook