dieselpilot

I had been looking for one of these small Emco machines for a few months. They aren't too common, but turn up here and there. I was lucky enough to find one close to home last week on craigslist. The price was right and it didn't have a control which was perfect. After digging into it it looks like it had a fairly rough life. I am going to have to come up with a chuck for it. I was told it had some kind of manual collet chuck being activated by an air cylinder. The motor is a 380VDC shunt type, 6000RPM max. I'll have to replace it with an AC motor and VFD I still have to figure out if it's OK to run a 3600RPM motor at 6000RPM by increasing the frequency. I was fairly set on servo motors with Gecko drives, but am reconsidering. There are 5phase steppers in the machine and 5 phase drivers can be found. The biggest problem with this project will be getting the turret working. I'll be using EMC for control.

Greg

flyinghospital

Hi Gary ,
if your using EMC then the toolchanger is quite easy to convert , their are 2 versions of the emco toolchanger , one using a dc motor and the other a stepper
but either way , it's not too bad .

i can help once you get to that stage if needed

Dave

dieselpilot

That sounds good. The guys on the Emco yahoo group made it sound like an impossible task. This is the earlier turret. The later turret is round, but I didn't know they changed motors at some point. This one does have the brush motor, but if one or the other is easier to implement that will be the deciding factor.

I did get all the cover panels removed. I'll have to get the bed casting off the frame to get this into my basement shop, then the fun starts. I did learn that running a motor at higher frequency is OK and just need to sort out what I can find, fit, and afford.

The Z axis ball screw has what seems like quite a bit of clearance. Are these preloaded originally?

Greg

dieselpilot

Progress has been slow with this. I did find an IEC100 frame induction motor and with help from Ken I, decided that would be the best way to go. I already had a open loop vector drive that I just pulled from my manual lathe after finding a $45 AB Poweflex 4 drive for it. I decided not to use the steppers, and have some dc servo motors on the way. Finding chucks for this machine has proven to be difficult. I'll probably end up with a 4" Bison 5C chuck initially.

Virtually everything is off the machine now. This machine is a mess, covered in grime and chips. It came out of a shop not school like most of these. Documentation I found online appears to say that the ballscrews are preloaded, but I haven't looked closely at their condition yet.

Dave, any help would be appreciated. It will be a little while before I get to the turret, but am hoping to be close to operational by the end of the year.

flyinghospital

your going with dc servo motors , how are you going to drive them ? , what about shaft encoders etc
how are you giving positional info back to emc etc .

toolchanger is not a major problem , iv'e just posted a toolchanger component on the linuxemc forum
for the dc motor type , it's quoted for Denford Orac , but the emco is Identical i believe .

dieselpilot

I'm going to start with Geckos and DC servos with encoders. I'm waiting for the servo to come in to very their specs, but they claimed to have 5000ct encoders. I already had the Geckos otherwise I may have done something different. I have a small mill using this setup and it has worked very well for me for years. By my math operating specs should be virtually identical to the original for speed, but with 0.001mm resolution. The only question is how much following error the Geckos will actually have in use. I jumped the gun and bought the stepper Mesa board for use with the Gecko's otherwise I might have tried to use EMC2 for feedback with simple servo drives. It looks like that is a much more expensive option though. I do have the original axis motors, but need to test them. The only reason I decided against Vexta 5 phase stepper drives is that I read they are low voltage so speed would be low.

rcfreak177

Hi Greg,

Nice find, I too am looking for a similar machine. Emco, Denford, Harrison, or Boxford cnc lathe with an auto tool changer for a refit project. It seems that they are as rare as hens teeth here in Australia. I have been searching in the USA and UK as well.
Good luck withe the project at hand and if you do happen to see a similar type of machine for sale PLEASE let me know.

Cheers Baz.

__________________
Fear and doubt knocked on the door,

Courage and confidence answered and there was nobody there.

dieselpilot

It seems the Denford Orac, Hercules Compulathe, and Boxford are much more common in Australia than in the US. In the US the Emco are much more common.

The servos arrived and they do have 5000 count encoders with what seems to be two sets of outputs. I think they'll have plenty of torque for the job at hand and the EMC setup should exceed factory rapid traverse speeds. I'm testing PCs for EMC. I had good results with an old Dell GX-150 933MHz on my mill and have another I'll be using as long as the Mesa card plays nicely. I'm still sorting out getting the lathe cleaned before bring it in the house.

I've had no luck sourcing the TOS chuck I want. The only contact I found in the US is dragging their feet with a quote, and I got no response from TOS or a vendor in Germany.

Greg

dieselpilot

I've managed to track down the lever actuated 5C chuck I wanted. The lathe is stripped down to the frame and awaiting some bright idea on how to clean it in the cold weather. I found a local machine rebuilder, but have not called asking for a quote. I might still drag it over to my father's and pressure wash the frame and bed casting outside in the cold, I just don't think that will get it clean. The grease on it is tenuous and barely washes off with any soap I have in the house.

I finally got a response from a tool vendor in Germany for the TOS chuck. Not cheap at something like 450USD with shipping, etc., for a 4" chuck, but they are supposed to be very accurate and with soft jaws it will probably be worth it.

The carriage and turret are in the shop ready to be cleaned and looked over.

Greg

dieselpilot

We had a very mild winter day so I gathered the parts and hauled them over to my parent's house to pressure wash. The sludge stuck on this machine was tenuous. The detergent for the power washer didn't even touch it. I'm sure the balmy 39°F temperature didn't help. I ended up using a spray bottle and a half of Zep heavy duty citrus degreaser and scrubbing with a brush, all parts at least twice, blasting away the grime with the pressure washer in between. Now, I have some mostly clean parts sitting in the garage. I wiped the ways of the bed casting dry and sprayed them with Corrosion-X.

All of the screws I took out are covered in the same slime. Normally, I put them in the ultrasonic cleaner which does wonders for screws and hardware. However, the detergent I use in it did have much effect on some parts I already tried washing. I'll have to soak them in the degreaser first.

Tomorrow, I hope I get a chance to get over to the hardware store and pick up some lumber to put together a base for the machine. Then we'll have some pictures of the rebuild. I have a new spindle motor and drive, axis servos, gecko drives, Mesa Cards. I think I'm ready to go except for small stuff like limit switches and wiring.



Greg