View Full Version : Making parts on my CNC lathe

11-27-2010, 08:37 PM
Actually did something with my little Hercus CNC lathe I retrofitted last year. I needed to make some adapters for work that adapted the old camera stands that used to hold Mitchell camera to allow us to mount Manfrotto pan/tilt tripod heads. The stands have a female 1/2-13 thread and the heads have 3/8-16. So I made a bunch of little adapter that go between the two. No cam was used in the code, but a little was generated in the Mach3 Turning Wizard.


11-27-2010, 11:03 PM
Cool! That's the highest speed threading I've ever seen-

11-27-2010, 11:06 PM
:) :) :) :)

11-27-2010, 11:12 PM
Looks like it works very well, also quite fast, that surprised me a bit.

Nice job on the Retro-fit.

11-27-2010, 11:23 PM
Thats only a fraction of what the servos can run at. Im limited by parallel port speed.

11-27-2010, 11:29 PM
I am a bit envious of you guys that can deal with the electronics, I started a Hardinge DV-59 CNC conversion, mostly have the mechanical stuff done. Although, at every turn just got more and more confused with the electrical end of it. That's not to mention the confusion on servo's, pulley ratios and a whole list of things beyond the basic.
Finally just quit and it sets on a bench.

Sets there on the bench with hundreds of dollars worth of THK rails, Servo motors, Rutex drives. :(

Pete F
11-27-2010, 11:30 PM
Is it a recommended practice to start with the shaft oversize, then turn down to size after the threads are cut? Or is that a CNC thing?


Erik Brewster
11-27-2010, 11:31 PM
Nice job! That was a fun one to watch the retrofit on the other thread. Even better to see it just making parts. Nice toolchanger :)

11-28-2010, 12:45 AM
I have found aluminum likes to move around a little and the OD on the thread crest gets a little bigger after cutting the threads. So it does two things, takes the major diameter to spec and kills most of the sharp edges. I rough to .375, thread, and then finish at about .365 to .370. That gives a very nice fit.

The finish is awful slow, but thats what the spec was on the data sheet for the insert. The insert is a little DCMT21.51 polished sharp insert for aluminum. Something like $6 a pop so I dont want to screw them up. Work did buy me inserts though. Got some nice TNMG222FF finishing inserts for the roughing tool (Any roughing on this machine is a finish cut in the real world.) and some more DMCTs in a more generic variety.

Its pretty cool though. I had never used a CNC lathe before this and its pretty nice to be able to tell it to go to a tool and just tell it the diameter and it will cut that. Still, for 90% of jobs I can do it on the 10EE and I dont have to think as much as I still have not figured a flow from cad to cam.

11-28-2010, 01:21 AM
Nice.... What is the top speed???

Makes you wonder how one ever made it to the US... But then Hercus did make the last genuine South Bends...

11-28-2010, 01:42 AM
3200 RPM Max. It has a Pratt Burnerd 3 jaw on the A1-4 spindle nose. The manufacturing version of the lathe had a power chuck on it. One of the guys here has one, which I would love to have. Yeah, good luck finding that...

My friend who I bought it from got it from an auction from the State of Washington. Probably in a school or something is my guess. I have seen a couple more here in the states on ebay but they seem to be very rare. If you do a search on it most results are mine.

11-28-2010, 06:13 AM
These are great little machines, I use mine mainly for threading using full form inserts so the crest of the threads are finished in the process.

11-28-2010, 09:51 AM
Nice job,last time you posted it seemed you were having trouble with the turret holding position,what did it take to fix that?

John Stevenson
11-28-2010, 10:24 AM
Sets there on the bench with hundreds of dollars worth of THK rails, Servo motors, Rutex drives. :(

Play a blowlamp on the Rutex drives, it will save them catching fire on their own later. :D

No seriously they are the most overrated drives I have come across, I have had them catch fire whist just sitting there doing nothing.

When you come to pick the project up again do a search for some decent drives.

11-28-2010, 03:38 PM
Nice job,last time you posted it seemed you were having trouble with the turret holding position,what did it take to fix that?

The mechanism uses a pin that has a cone shape tip to push into the turret wheel which has cone shaped recesses in it to lock into place. This allows the turret to align when it locks. As far as I can tell cutting forces were pushing the pin back and rotating the motor in reverse and loosening up. So I installed a resistor that keep current in the motor to keep it locked. Seems to work pretty well. It still may be a bit low. I am not sure if they just locked the motor or what in the original design since none of that was working when I got it and I never really traced it out. oops on my part.

Ahh, the rutex's are not that bad if you keep them in liquid nitrogen... ;)

I have gotten real good at repairing gecko's lately. Must have done 8 in the last month or so.

11-28-2010, 11:52 PM
When you come to pick the project up again do a search for some decent drives.
Yes, every thing read on them was/is not glowing, but you find that with absolutely anything and everything on the internet, even women :D
At the time, from what I was able to glean from the text was that most all are for Steppers, the only others with HSM type support seemed to be Rutex and Gecko's. Problem is, wouldn't know a good drive from a bad one, appropriate drive or not and some got way out of line for me dollar wise.

Every time I see something like macona's conversion it prompts me to pick it up again.

11-29-2010, 12:00 AM
Now there are all sorts of drives out there for permanent magnet dc servos. No longer are you limited to geckos and rutex. In my opinion geckos are near the bottom for servo drives from use on a friends CNC router.


11-29-2010, 12:34 AM
Thanks macona,
That is an informative link.
I'd been watching the Granite Devices from before their actual production. They have always looked good. Now the XE version appears to be capable of handling two Brushed DC motors which is very interesting and brings the price to affordable.