View Full Version : New? CNC Mill Design

Spin Doctor
10-09-2005, 11:57 AM
Saw this one on eBay

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7552074104&indexURL=0#ebayphotohos ting (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7552074104&indexURL=0#ebayphotohosting)

Any body know any thing about these guys. I am assuming thatn the basic machine is Asian but?????

[This message has been edited by Spin Doctor (edited 10-09-2005).]

10-09-2005, 12:32 PM
I think they were talking about the same mill here

Spin Doctor
10-09-2005, 12:37 PM

10-09-2005, 01:59 PM
At only $6800 it's hard to imagine it being a really great machine.

10-09-2005, 02:14 PM
Quick! Hide this from Adrian. Hell have one by the end of the week http://bbs.homeshopmachinist.net//biggrin.gif

10-09-2005, 07:41 PM
If you read through the write up, they state the machine is made in China with US supplied electronics. Tormach makes a very nice rapid tool changer (manual) for R8 spindles that is fairly inexpensive and is featured on this machine. The tool holder fits in the spindle and tools can be rapidly (seconds) popped in and out for serial operations. Cost in the sub $500 range with lots of tool holders.

[This message has been edited by sch (edited 10-09-2005).]

Paul F
10-09-2005, 09:29 PM
For us home-shop non industrial types, $6800 is still a lot of money... but it looks pretty good (given the size) for a lot of stuff. At least for stuff I do (or would like to).

Another couple years, if and when they drop to sub $5000, maybe I'll be able to afford one...

Paul F.

10-10-2005, 12:04 AM
<font face="Verdana, Arial" size="2">Originally posted by Paul F:
For us home-shop non industrial types, $6800 is still a lot of money... </font>

agreed Paul, I don't think the comment is belittling the amount money, but rahter comment on the nature of a cnc machines the $$$ it takes to make a decent cnc mill is much greater than what it takes to make a decent manual mill, so there's disbelief that its much good for $6k. for example, most would want ground ball screws, zero backlash nuts, precisions mounting blocks etc - that alone can be a couple of grand per axis.

the diy that wants a serious machine takes an old bridgeport or something and converts it sourcing the expensive stuff on ebay - my guess is you'd get several magnitudes better a machine afterwards than this puppy.

10-10-2005, 12:28 AM
I like the "photograph of ...the resulting work." Sure looks like a rendered drawing to me. Either that or the thing can sandblast, too.

Milacron of PM
10-10-2005, 07:20 AM
Doofus looking little bugger....wonder if the designer is the grandson of whoever designed the US Burke mill ? http://bbs.homeshopmachinist.net//smile.gif

Yeah the finished part example does look a bit like the ones Roger Rabbit ordered from Toontown.

10-10-2005, 07:54 AM
Not a defense or testimony to the machine but on close reading the "finished" part referred to IS a drawing: "The three-photo sequence has the TurboCADCAM design, work in progress, and finished work shown adjacent to an 8” caliper to get an idea of the size."

Looks like they left out the "finished work shown adjacent to an 8” caliper" photo though.

According to the sheet it seems the machine does have ground ball screws: "Precision ground ball screws in the X, Y, and Z motion." And "We use the double nut technique for anti-backlash ball screws."

The table size seems nice...I'd be a little worried about the "Max spindle nose to table - 17inch" dimension...and the price is about an order of magnitude out of my range!!

10-10-2005, 10:24 AM
OK...I'l admit I didn't read the whole thing...So what makes this a "NEW" design???

Spin Doctor
10-10-2005, 10:56 AM
Actually I don't think of it as a new design in terms of the overall design itself. Perhaps I shoud of said new manufacturer or whatever (the only really new machine types in the last 50 years are the Hex-a-pods and Stereo Liths). Given the costs of the converted Mill/Drills I have seen on Ebay the price might not be that bad. The other thread on the forum that mentions this has a post from John Stevenson in which he says he was reasonably impressed with the quality. Looking at the part sheets included in the auction page the ballnuts are the non-recirculating type that are also found in BP conversions, there are angular contact bearings are both ends of the spindle (unlike a BP that has them just on the tool end along with on the motor end of the ball screws. Given the over all weight and size for a HSM with money to burn (and no desire to convert a manual machine) it might not be too bad. But if you had the room why not go bigger. Actually unless one is doing contour work I personally don't like 3 axis CNC unless they are full blown machines. CNC converted BPs I prefer to be 2 axis with manual control of the z axis. But thats just me.

Besides compared to this

http://cgi.ebay.com/Custom-LG4-Desktop-CnC-Milling-Machine_W0QQitemZ7552759271QQcategoryZ12584QQrdZ1Q QcmdZViewItem

[This message has been edited by Spin Doctor (edited 10-10-2005).]

10-11-2005, 08:24 PM
Hi Guys, G. Jackson of Tormach here.

RE: comment on missing ebay photo.
Sorry I had dropped off the finished work photo on the Ebay listing. I have that back now. Please feel free to point out these things via email to me direct. I don't have much time to get out to discussion groups.

Regarding some other comments in the thread:

The machine design is indeed conventional. We refer to it as "totally new" because it was designed from the ground up and just recently released for sale. Every casting is new, this is not a recycled version of some other design.

It's perfectly legit to have two sets of preloaded bearings in a spindle, as long as the spindle is short and designed such that the spindle will remain close in temperature to the spindle bearing mounts. This is one of the reasons we used a cartridge style spindle.

Lots of home shop machinists look for ground ballscrews over rolled ballscrews. This really is not enough since lots of manufacturers make low grade ground ballscrews. The better criteria is to ask what the ISO/DIN grade is. Most retrofits are done on grade C7. Haas uses C5. Our machine is P4. On short lengths P4 and C4 are the same. P4 is more accurate than C4 on long lengths.

I'm not sure what the comment on non-recirculating type ballnuts is. All ballnuts that I know of recirculate. Some do it through tubes molded into an internal plastic carrier, some do it through external bent tubing. Not much difference in performance between the two designs as far as I know.

So far, most of the mills have been sold to light industry and small machine shops. It's curious to me that few home shop people pick up on some of the more aspects of the design. The use of a Turcite style slide surface is expensive and normally only found on much higher priced machinery. Lubrication is another big deal. There is a great deal of time required to cut oil flow channels in all 12 of the sliding surfaces, not to mention all of the plumbing for the oil lines. The professional shops value these features highly.

G. Jackson

Note: I hope serious questions are copied to me through our web site. I don't have time to get to this discussion forum much so you might not get a prompt answer here. Thanks.

John Stevenson
10-12-2005, 03:44 AM
<font face="Verdana, Arial" size="2">Originally posted by Spin Doctor:
Actually unless one is doing contour work I personally don't like 3 axis CNC unless they are full blown machines. CNC converted BPs I prefer to be 2 axis with manual control of the z axis. But thats just me.


I don't follow your reasoning on this.
You don't have to be doing contour work to make full use of having the Z axis under CNC control.
I don't do contour work but for me only having two axis under CNC is not a lot of use.

A classic example is a bolt circle.
That's not contouring and I expect to load the program, hit go and walk away.
With only two axis under CNC it would place the fist hole, then I would have to drill it by hand, direct it to the second hole then repeat.
In this case not much saved over a manual machine with DRO.

John S.