Considering CNC Mill... what should I look for?

[matthewsx]

I might not be the ideal person to ask since I only have a CNC and I'm still building it & figuring out how to use it. I do miss my Gorton 1-22 MasterMill though and often think of how useful it would be for building my CNC.

Honestly what I would suggest is getting a very capable manual machine first. The job shops I've been in have both the big VMC for running production jobs and a Bridgeport for one off's and building fixtures.

Then, once you get more comfortable with your 3D printer and have some experience with the manual mill you can decide if you want a full blown VMC, a smaller hobby type CNC like a Tormach, or want to do a conversion of another manual which you will be better able to accomplish with your existing manual machine for making parts.

Since you're just getting ready to jump in there's really no way to know what you don't know. This place is great but we all have our own experiences and resources, probably different from yours. If you can design and print cool stuff on your 3D printer then you can transfer those skills to a CNC, but there are still going to be times when you just want to put a piece of metal in the vise and drill a few holes.

The part about enclosures is definitely something to consider, from my limited experience CNC throws a lot more chips and flood coolant is probably mandatory for taking big cuts. I definitely want to build one for my little mill/drill project but that will limit the size of part I can work on. In a home shop you will have both projects you design and build from scratch and repair jobs that can sometimes be odd shaped or bigger than the table on your machine. Factor that into your decision making as well.

If space and money weren't a problem I would probably have one of the combination horizontal/verticals like the Wells Index you were looking at in the other thread and a Tormach with a full enclosure. We actually have a Tormach dealer in town here

JMHO,

John

 

[BGHansen]

Here are a few Craig's List machines in your general area. I used the search engine "www.searchtempest.com". Plug in your zip, max distance, and a price range if you want.

Bruce

Looks to be a 4-axis Sherline mill and lathe for $3500

Plug and Play CNC workshop - tools - by owner - sale

Thousands of things can be made with this setup, CNC lathe and 4 axis mill, has everything to get...

gadsden.craigslist.org

Meaty, beefy Seki 3-axis with a 10 x 54 table. Has an old Anilam controller (1100?). Asking $6500

Seki XL 3 Axis CNC Mill - tools - by owner - sale

Selling a great Seki XL Knee Mill. It is a full 3 axis CNC with Analim controls. Can be used...

atlanta.craigslist.org

Round column Rong Fu type mill, 3 axis. Seems a bit high at $7500, especially with no tooling pictured.

CNC Milling Machine - 3 Axis + - tools - by owner - sale

CNC Mill 3 Axis Plus Port for 4th 230 VAC Single Phase Dell Computer Monitor Keyboard & Mouse...

charlotte.craigslist.org

Small Boxford table top 3-axis, asking $5000

CNC Milling Machine - tools - by owner - sale

Boxford model 190VMCxi, 3 axis CNC Vertical Machining Center featuring Boxfords Complete Software...

charlotte.craigslist.org

 

[ArmyDoc]

Yes, familiar with search tempest. Of the ones you posted, the seki XL is the one that most interests me. Only concern is very old controls.
I'd be interested to know what others with more experience think about those machines, as well as these three:

Tree Millennium 3100 3-Axis CNC Vertical Milling Machine - The Equipment Hub

Visit here to learn more about this Tree Millennium 3100 3-Axis CNC Vertical Milling Machine for sale. Contact us today for additional details.

www.theequipmenthub.com

Bridgeport EZ Trak 9" x 48" 2-Axis CNC Vertical Milling Machine - The Equipment Hub

Visit here to learn more about this Bridgeport EZ Trak 9" x 48" 2-Axis CNC Vertical Milling Machine for sale. Contact us today for additional details.

www.theequipmenthub.com

And

Bridgeport Series II Interact 2 3-Axis CNC Milling Machine - The Equipment Hub

Visit here to learn more about this Bridgeport Series II Interact 2 3-Axis CNC Milling Machine for sale. Contact us today for additional details.

www.theequipmenthub.com

 

[Aaron_W]

I appreciate the advice, and caution I hear in your post. I do have a 3D printer that I bought last year. I've only done one project from start to finish yet, but it was a lot of fun. It's a 3D puzzle, octogon in cross section, that twists on it's central axis. There are 4 oval tracks of marbles that when you twist 45 degrees become a spiral. Mix up the marbles, then try to figure out how to get them back to start. I got the idea from a hexagon one that I saw on line and printed. Here's a link to the one on line that I printed.

Here is mine in each of the 4 orientations before returning to the original, but 180 degrees from start:
View attachment 335891View attachment 335892View attachment 335893View attachment 335894View attachment 335895

As you can tell, while I was able to make it, I haven't solved it yet!

Ok then you at least have an idea what you are getting into with a CNC machine. It seems like a lot of people think they are like a Star Trek replicator, and don't realize there is work involved it getting a nice part out of it.

 

[BGHansen]

No direct experience with those machines though our Tool Room at work has a BP Series II GARGANTUAN mill like the one pictured. Check the ad, no skidding fee as it weighs 5000 lbs. The one at work has what looks like a similar controller. The on-board memory is limited, so they dip-feed from another computer.

Our Tool Room also has an EZ Trak BP though it has a 42" table. Problem I see with this one is it's 2-axis. My BP has 2-axis also, you'll want the 3rd axis once you get a taste of 2-axis controls.

Tree made good mills I believe in Racine, WI. I have a buddy who taught at Gateway Technical College in the Machine Tool school in Racine, they used Tree mills there at the time. The control is an older Anilam 1100 series. Like Jim Dawson mentioned, the controls can be replaced with a Galil or Centroid card. You might check with Jim as he's the expert, but the servos on the machine would probably not need to be updated.

Kicker on the BP Series 2 and Tree is the Z-axis controls appear to be on the quill which is typical. It gives you ~5" of travel in the Z-axis under program control.

Bruce

 

[ArmyDoc]

No direct experience with those machines though our Tool Room at work has a BP Series II GARGANTUAN mill like the one pictured. Check the ad, no skidding fee as it weighs 5000 lbs. The one at work has what looks like a similar controller. The on-board memory is limited, so they dip-feed from another computer.

Our Tool Room also has an EZ Trak BP though it has a 42" table. Problem I see with this one is it's 2-axis. My BP has 2-axis also, you'll want the 3rd axis once you get a taste of 2-axis controls.

Tree made good mills I believe in Racine, WI. I have a buddy who taught at Gateway Technical College in the Machine Tool school in Racine, they used Tree mills there at the time. The control is an older Anilam 1100 series. Like Jim Dawson mentioned, the controls can be replaced with a Galil or Centroid card. You might check with Jim as he's the expert, but the servos on the machine would probably not need to be updated.

Kicker on the BP Series 2 and Tree is the Z-axis controls appear to be on the quill which is typical. It gives you ~5" of travel in the Z-axis under program control.

Bruce

Do you think 5" is problematic? If I ever did a 4th axis (which seems likely to me) it would give a 10 inch swing...

 

[JimDawson]

Do you think 5" is problematic? If I ever did a 4th axis (which seems likely to me) it would give a 10 inch swing...

You have about 5'' on the quill, but the knee will give you another 16'' or so. The knee will bring the table up to almost touch the retracted spindle. A 10'' swing on the 4th axis is more than enough.

Of the mills above I like the Seki, but that's just because it is most like mine.

 

[BGHansen]

The 5" travel isn't problematic as those mills don't have a tool changer. The Tormach has about 16" of Z-axis travel. Mine has a tool changer too. Advantage of the added travel is if your part requires tooling with too wide range of tool heights, you don't have to touch the knee to a pre-determined spot for the tools.

For example, my Tormach tension/compression tapping head has a tool height with a tap in it of around 8". An end mill holder with a short end mill is around 3". A larger drill chuck with a jobber length drill is about 6". A I can run the job from the tool changer and walk away, the 16" of travel can handle the big range of tool lengths.

Same job on a 5" travel machine would require some planning for knee table heights, so no "lights-off" walk-away from the job. Not a big deal as all of the tool changes are manually done, so you need to tend to the machine. Another thing is spindle control. Don't know if the EZ-Trak BP has spindle speed control via the CNC. The one we have at work does not. On my Tormach the speeds are under program control so a tap drill could be at 2000 RPM, then tap at 200 RPM. Again, not a big deal as you are doing the tool changes manually anyhow.

Bruce

 

[7milesup]

Interesting thread ArmyDoc. I have been thinking about converting my 833T to a CNC machine. There is actually a conversion kit for it and even with the cost of the kit, the electronics and the mill itself, you end up way less than a comparable Tormach or similar. To me, for the money, you just can't beat it, but of course that is dependent on what you want to do and how big of a machine you need/want. I don't have anything against Tormach, but when I look at value, this conversion is high on that list...---> 833TV to CNC conversion. He lists all of the parts he used and how he went about it. The biggest issue for me is my 833T is a geared head and I would want to convert it to a variable speed belt drive, which will take some fanangling. The 833TV has the belt drive head so that is no longer an issue. Plus, you get a new machine with a 5 year warranty.

 

[ArmyDoc]

They have a kit for his conversion too. https://www.heavymetalcnc.com/pm833t/ Pretty nice.

I think the hardest thing for me is know is how much mill I'm going to need. If I go CNC, I will definitely want to have 4th axis capability at some point. Even in a manual mill, many of the projects I envisions require some kind of rotary table to be able to complete them. This requires a larger table, and I think the desktops are just too small. I don't know the exact size of these devices, but I'm guessing 8-12 inches by the time you include a chuck, and if you need a tailstock support, that's even more space gone. I suspect a 35 inch table is as small as I should consider, and probably need to be looking at the 49+ sized machines.