cnc micro mill

SVanderkolff

SVanderkolff

Joined
Oct 31, 2002
Messages
979
I have the opportunity to buy a desk top micro mill complete with a cnc setup. I was wondering if anyone else uses a cnc machine with a micro mill and if so what for. My thought was simply guard slots as a start. My DRO system for my mill just died and the mill I have is in pretty rough shape so replacing both would cost me far more than would this cnc machine. I guess i am just asking for advice and input. Not something I need to have but since the opportunity is there it seems like a neat toy to play with.
Thanks for the input.
Steve
 
Do you know how to operate a CNC mill?
What brand is it?
CNC conversion, or factory set up?
 
It totally depends on the desktop mill you're looking at. I've got one I've used for a couple of years much like this: http://www.ebay.com/itm/201173021547?

It's too small for serious milling of steel - using an 1/8" endmill it will mill a couple thou cut, but that's about it. Just too much flex in the system. I do use it a good bit for engraving in blades before HT'ing. That works pretty good. My main use when I got it was making PCB boards for electronic projects.

I suspect the next size up would work better - the 6040.

Keep us posted on your decision and what you get, and how it works. I use LinuxCNC for the CNC program - really a NICE program and it's open source.

edit: if you want a "real" machine, take a look at this one: http://www.ebay.com/itm/171784801517?

Ken H>
 
Bill
I have never used a cnc machine before. It would all be new to me. I barely know how to use the mill I have but thats half the fun.
Ken
I don't think that second machine will fit on my workbench, or through the door for that matter.

Steve
 
I suggest you look into programming for the CNC before you buy one.
 
What have you got now ?

How much money do you want to spend ?


Some have conversational programming on the machine.




The bigger the better.
 
Right now I have one of those $900 harbor freight machines. The machine I am looking at is basically the same mill but is set up for a 3 axis cnc with servos and Mach 3 programming with a computer. The guy is looking for 1200 for the complete set up. As I said my DRO just died and that is over 500 to replace it so thats why I am thinking for a little bit extra I can get something better.
 
I have used enough small machines to say I would rather have a larger, sturdier $1200 manual mill than a smaller, flexier $1200 CNC mill.
 
I have a Taig mill that came with all the CNC stuff. I took it off, and converted it to a manual mill. If you want the controller, servos and stuff, let me know.
Mach 3 is Greek to me. You might go to their web site and download the demo copy and try to figure it out.
 
I wouldn't go there. Unless you're an enthusiast that knows these systems inside and out and likes tinkering with things, it's likely to prove to be a big waste of money for you.

1. Micro mills tend to lack rigidity required to realistically machine anything more than wax or plastic--maybe wood.
2. Unless there's support available, I wouldn't touch it no matter what. (Support meaning you can call a tech on the phone or get someone out to look at it).
3. Old or odd-ball CNC equipment/software is simply not worth messing with (IMO). Software is generally harder to learn, and learning weird proprietary stuff is not as smart as spending the time learning something a big community of users is using (again, support from forum users, etc.).

This is the catch: the guy starting out is most likely to go cheap, and that means old or odd ball machines.
Old machines are not the best choice for new users because the new guy often isn't equipped to discern a machine's condition upon purchase (repairs are usually big $), and weird old stuff just isn't well supported buy companies or a large user community.

I know it's hard, but the best bet entering CNC (and ironically the cheapest in the long run), is to get a new machine like one of those Tormach things or a Haas.
A Haas or similar would be preferable because of the tremendous support available, the huge number of machines in use and, consequently, huge number of users --- Peer and factory support. --But they're gonna start around $30K. Because of the support available, however, you can find a used Haas and have a factory tech check it out. Problem is these machines hold their value well and you don't always save a whole lot compared with a new machine.
The Tormach is not near the machine, but they do offer factory support and seem committed to being around a while, which makes it a much much better choice than a questionable old machine, IMO.
 
Last edited:
As a full time machinist my recommendation is get as much experience under your belt with a manual machine so you understand the machines capabilities when you have spent a couple thousand dollars on materials and have a full grasp of waste then consider CNC.
 
AWwww folks - don't bad mouth CNC mills so much. They're not "that" hard to use..... well, that's for somebody who's fairly computer literate and has a bit of programming skills. Nathan is the real guru here on CNC work.

Steve - if you are not familiar with CNC programming, download Mach3 (Mach 4 is now out) for a test run. OR - if you can use Linux at all, go for LinuxCNC. Just as powerful, maybe even more so than Mach 3. You will sorta need a computer to dedicate to the CNC mill. With this running on your computer (even before you get the mill), you can test your ability to work with CNC stuff, run simulations to see how the code runs. Lots of learning you can do before getting the mill. BUT - for $1200 for that used setup, now you're talking a real CNC mill and you can do LOTS with that. It sounds like the mill might be one of the X2 versions out of China? They're good machines, basically the Grizzly G0704 mill. For $1200 and it CNC'd - darn good deal - wish it was closer to me, "IF" you decide to pass on it.

Ken H>
 
For a part time maker who is looking to slot guards a CNC is over kill. I have been making parts that fly in space for years and learned on conventional equipment and went to school for programming when our shop was refitted to new CNC equipment and at home doing my own knives I have never had a need to run CNC programming. If you intend to make a living and mass produce then CNC will be a benefit down the road and taking classes will be beneficial to learn all that these machines are capable of producing. I would love to own an EDM though....:cool:
 
Ken H> said:
edit: if you want a "real" machine, take a look at this one: http://www.ebay.com/itm/171784801517?

Ken H>
Click to expand...

^ I don't know man! I'm a big fan of Fanuc motion control, but that's a 3M controller! I think that's older than a lot of cnc machinists these days! No look ahead, not much memory to speak of, analog DC drives, hasn't had factory service parts in a looog time. I wouldn't even mess with a 6M. That thing should be in a museum!

Early 90's or newer for any semblance of competent motion control for CNC machining knives. Stay far away from 70's and early 80's stuff...


I had a pretty nice little CNC mini mill for sale here a year ago (it's gone now). About 3-4 HP in about 3,500 lbs mini mill with 9"X14" travels (edit: take note the weight desired for even so small a machine that's going to do very well cutting knife steels) and a little 30 taper spindle good for 5,000 RPM, in very good condition. Perfectly suitable for light cuts in steel and relatively accurate machining. The sort of thing that would be a fine little cnc mill for knife work and I think it sold for about $3,800 (it sold on the bay, nobody here even wanted it)

Good deals on appropriate machines can be had for under 5K but it won't be under 1,000 pounds or over 30 years old.
 
Last edited:
Nathan - I just have to smile when you mention a mini mill and say it's about 3,500 lb!!!

I agree with all comments that say CNC is NOT dollar wise for knife making, especially at a hobby level. BUT - it's sure a lot of fun playing with, and even the true desktop mills I linked to above will do nice engraving. BUT - as mentioned, there is a pretty steep learning curve. I am NOT by any means the expert Nathan is in CNC programming, but it's a lot of fun playing around with.... and useful also. BUT - NOT useful enough to justify for just knifemaking unless you're using it for other things also, or just like fooling around with programming.

Ken H>
 
Well, I passed on the chinese knockoff cnc mill but now the seller has offered a prolight 1000 also at a very reasonable price. This seems to be a much hardier bench top model. I guess it comes down to whether or not I want to spend my time making knives or learning how to operate a cnc machine?
Anybody have any experience with the Prolight 1000 series?
Thanks
Steve
 
Ken H> said:
Nathan - I just have to smile when you mention a mini mill and say it's about 3,500 lb!!!

>
Click to expand...

Oh yeah man! I have a mini mill that we use pretty frequently here in the shop. It's a tiny little Romi D400. It's pretty typical as a small mill that might be used for second ops or drill and tap. The travels are 12"X16", fairly common for a minimill and not much bigger travel than a desk top toy, and it weighs just over 6,300 lbs. It's competent in steel if I don't get in a hurry and if I stick to cutters under 1/2".

One way to look at this is deflection and play in comparison to chip load. Unlike aluminum, plastic and wood, knife steels have a narrow processing window. Take a 1/4" end mill in 3V. If you feed it over .001" per tooth the edge will overload and start to break down. If you feed it under .0002" the material being cut doesn't cut but rubs and smears instead and the carbide content of the steel wears down the cutter and the steel work hardens. So you have a window of .0002"-.0010" to achieve good cutter life and cut results. That's a range that's about half the thickness of a sheet of paper. If your cutter and spindle and spindle casing and column and the rest of the casting including any play in the table, stretch in the ball screws or flexibility in the screw mounts and other anchors and structure of the machine allow just .0005" total play and deflection in that cut while making chips, your tool life and accuracy and finish are going to suffer. So you see, it takes a pretty stout tool to do well in knife steel. Yes, you can certainly get by with much less, but CNC + knife steels really benefits from a little extra heft.
 
I have a Sherline 5400 that we upgraded with a 10,000 RPM spindle along with high speed screws and modern backlash control. I use it for high speed engraving. When I want to cut slots in handle material I disconnect the drives and operate the machine by hand. Learning to write code for a CNC machine will be a fun challenge and it is doable. If you don't have a use for the skill, purchase a better manual machine and leave the CNC to someone who has a use for it.

What's your heaviest machine in your shop Nathan?

Fred
 
You must log in or register to reply here.
Back
Top