Thread: Beginners 80% rebuild of an emco compact 5 CNC lathe

I recently got a somewhat beat up Emco Compact 5 CNC lathe. I spent a bit of time retrofitting it. (Note: "Emco" is Austrian lathe as opposed to "Enco," cheap Chinese) While the manual has a schematic, I didn't see much on taking it apart, which is a bit nerve wracking since Emco doesn't seem to make replacement parts. This is the first chunk of photos from what I did. No guarantees it will help, but perhaps you can at least see things to avoid.


NOTE: this writing is *way* too detailed for a real machinist. It includes a bunch of very basic steps since that's the level I'm at.


So here's what we have to work with:



Pretty dirty, some rust spots.

The spindle moves if you manually program it, but there's no way to save programs other than a tape player(!) and no way to upload other than typing.

I bought a plug&play CNC setup from dmauch@seanet.com, which includes a set of Nema 23 500oz motors and a GeckoG540 controller. You can drive it using Mach3 or (hopefully EMC2).

In any case: first thing is to strip the lathe down.

Here's the back, with all the old electronics's. The backplate screws right off. Most of the electronics are attached with small hex screws.



The main board comes off pretty easily:



As does the tape drive:



I especially like removing these since we don't have to remember how to put them back!


The bare space left:

Since we're replacing motors we skip ahead and remove them just to see if it's going to be a pain to bolt on the new ones:




A few hex nuts off and we're good to go. The new motor on the left, old motor on the right:




The top of the topslide comes right off, exposing a bunch of gunk:



There are two bolts on the bottom of the lathe bed. Remove them, and off comes the bed:




To remove the entire cross slide you undo a fair number of hex bolts on underneath it:



Winding up with this when you're done:





The plastic that holds the ballscrew connector is definitely cheap, and broken. You can also see where some jackass ran into the headstock, bending the metal that holds the oiled felt against the ballscrew:


Remove a couple of bolts and off comes the short cross slide ballscrew:



Unscrewing the protector:

The bed is held onto the headstock with four metric screws.


But not for long!


The condition of the bed is criminal. As expected since the machine came from a school.




We unscrew a few bolts and off comes the motor:


Leaving the frame:



Two bolts on each side and the electronics enclosure comes off as well:


Now we need to get the pulley off of the old motor. First knock out the
pin:


Then pry it off with a knife (should have used something else, obviously):



Leaves:

The wrong thing to do is to remove the spring washer at the end of the pulley, since that accomplishes nothing, other than losing the washer. Ask me how I know. This is one of the many cases where The Right Way to do something feels wrong --- if you pull on the pulley, it won't budge, so you figure there must be a different way. But no: in this case using brute force is actually the right way. Who knew.

For example, to get the spindle out, you have to remove the pulley at the rear of the lathe. But if you pull on them, even with some effort, they won't budge. Which of course means we just have to pull harder! The main trick is to not break the not-that-sturdy plastic on the pulley. So we use a "pulley puller" (I kid you not: that is the name). Three prongs with a central screw that you screw down that slowly exerts significant force and pulls a pulley off.

Here the pully puller is attached to the pulley (on the spindle), along with a metal plate since the center of the spindle is hollow:


Bingo, comes right off. And then the spindle does, and then the headstock. It's disassembly jackpot:


The only thing left is the bearings. If you push on these they don't want to come out the front. The wrong thing to do is to try to get the snap ring on the inside out (not shown since this is wrong). What we should obviously do is do more of what wasn't working! If the bearings don't come out with a small bit of force, hit the suckers! You want to be careful here and (1) use a wood dowel with a fairly large diameter and (2) tap them out evenly rather than just hitting one point. I didn't do (1) (used a brass rod like an idiot) so bent one of the bearings as you can see --- I was going to replace it anyway, but still it's pretty stupid. Note that there is only one wavey washer (for the back). It's easy to think that when you hit the bearings out that you lost one. An odd asymetry:





Next we scrub with industrial degreaser. This stuff is great, but it will remove many different types of paint, so only use it when that is ok:


Degreased before painting:

This is a delayed continuation of the above where we put the machine back together with new bearings, motors, etc. I did this a month or so ago; hopefully this doesn't leave out anything important.

It's currently at around 80%: motors in, everything turns, but still have:

• hook up limit switches, the motor, the shutoff switch, and the RPM encoder to the gecko g540.
  
• do something about the cosmetics: I ripped out a bunch of the stock electronics, leaving empty holes. These will suck up dust and junk, so need to decide what to do.

It's largely straightforward to put things back together. The two tricky things are:

• getting the optical encoder to not drag as the spindle turns. It turns out you have to bolt the lathe in and push/pull it back and forth so that the sheet metal of the housing torques until the drag stops. I kept disassembling the spindle head (and trying to seat the flywheel assembly deeper) in a misguided belief that these were the problems.
  
• You probably 't just bolt the motors right on and go --- you need to make sure the tension is sufficient. So push the motors away from the timing belt wheel until the belt is tight and then tighten the bolts.

Finally, I still cant' get mach 3 to run reliably on windows XP on a Thinkpad T61 laptop, but this seems to be a known problem.

OK: first things first, getting the new 6006-ZZ class 3 bearings into the headstock. This likely made little difference, but I put them in the freezer to hopefully make it a bit easier --- it was suggested I use dry ice, but I was too lazy.

One thing I'm disappointed about is that the headstock is aluminum, which seems kind of cheap given the general quality of emco stuff. Maybe worth redoing in steel at some point? In any case, here's the headstock and bearings (in a few freezer bags to eliminate moisture):


One slightly confusing asymmetry is that the number of pieces is different in the front and the back. Front has just a bearing and a ring:


Back has bearing, wave washer and ring:


This can lead to a bit of panic when you disassemble (at least for me) where you disassemble and think you lost something in all the excitement.

Putting in one of the bearings: we use a flat piece of wood to give contact and minimize chance of dents:


Next is putting in the spindle. Here's the spindle from a real lathe (a Hardinge/Cataract) for comparision. As you can see, not much of one:


The spindle is a tight fit, but if it requires a lot of force, the bearing is probably not seated:


We put the pulley, etc on and then lock it in with the ring:


Now time to bolt on the motor:


Note that you can't tighten the bolts here down until you adjust the belt tension. The small hole in the pulley is provided so you can tighten the bolt behind it:


Time to put the felts back on the cross slide:


And then bolt it back to the bed using the plastic (yeah, I know) supports. Note: you don't want these too tight or the bed won't be able to move!


Now we bolt the top to it:


And, in the interests of full disclosure, at this point I discovered I left a bushing off of the spindle. ARGH!!!!




So we use the pulley puller to pull off the pulley and on it goes.

The new nema23 motors I have don't have holes in them for the pulleys that came with the emco. So we use a small proxxon drill press to drill a hole in from the flat part of the motor spindle to the back. Starting (note: during the actual drilling there was support on the spindle to avoid bending anything):


After:


And banging the pin in using a bench block:


In good news, they bolted right on:


At this point we get to the most annoying issue: when you turn the spindle, the optical encoder on the machine (the part with the cable in the photo) would rub no matter what we did. It seemed that the spindle was off center (which it wasn't):


First problem is that you need to bolt the housing to the lathe body:


Second thing is you need to push/pull the lathe bed back and forth, spinning the spindle til it stops rubbing. Then bolt everything down to keep it in this configuration. I am not a big fan of this design methodology. I much prefer things that when in their right configuration are, in fact, in their correct configuration. Having to bend things about is too ghetto.

In any case, success, so we move on.

A bit of adjusting of the cross slide since it was too loose and wobbled back and forth:




Now just have to bolt on the top part:


Clearly something has to be done about all the holes from missing electronics:

And here's everything bolted up. One step you didn't see was adjusting the belt tension on the motors: loosen bolts, push the motor away from the belt pulley and tighten.

Originally Posted by coltz

NOTE: this writing is *way* too detailed for a real machinist. It includes a bunch of very basic steps since that's the level I'm at.

Wow. You are right....
Maybe you should move this over to the *******.
We have not learned how to turn pencils yet.

Originally Posted by Polaraligned

Wow. You are right....
Maybe you should move this over to the *******.
We have not learned how to turn pencils yet.

In case it wasn't clear: the disclaimer was saying that I was a beginner, not the people on the forum.

I see a lot of new people buying these machines for retrofits --- I'd have liked to see a detailed set of steps when I took apart mine, so assume they would as well.

Obviously, this isn't a particularly useful post for anyone who is a real machinist. But I assume they'd skip as soon as they saw the machine weighs only a couple hundred lbs...

Nice job, what did you do with the tape drive and original stepper motors??
Dave

Originally Posted by SchneiderMachine

Nice job, what did you do with the tape drive and original stepper motors??
Dave

Thanks! It's a nice build to get started on CNC retros with. Really took the mystery out of things --- isn't much too a lathe in the end, which was not my impression at the beginning. A week later I was taking apart the headstock of an old hardinge (from necessity, unfortunately) and actually got it back together in better shape than when I started despite no instruction manual.


Tape drive is yours if you want it. I don't have any use for it.

The steppers I'm holding onto while I try to sell another Compact 5 CNC PC. If they aren't needed for the sale, I'd be happy to sell them to someone.

Hell yeah I'll take it, maybe it'll work in my machine. Mine doesn't work, hasn't worked for, oh, 20 yrs. I have a Compac6 Emco.
I wonder if the steppers are the same?? Mine have different heat sinks on them.
Thanks,
Dave

Schneider Machine
15275 Martha St
Hamburg MN 55339

Originally Posted by SchneiderMachine

Hell yeah I'll take it, maybe it'll work in my machine. Mine doesn't work, hasn't worked for, oh, 20 yrs. I have a Compac6 Emco.
I wonder if the steppers are the same?? Mine have different heat sinks on them.
Thanks,
Dave

Man, if you have the stomach to use a tape drive to control the machine you are welcome to it. That is very old school.

I'll send it off priority mail sometime this week. Note: I'm not at all sure it will work on a compact 6.

Not for controlling it, it's for backup or loading the MSD files. (parameters)
I have the tape, the drive don't work. For free I'll give it a try, if it don't work I'm not out anything.
You really don't want to know how much Emco wants for a new drive.
Dave

Originally Posted by coltz

In case it wasn't clear: the disclaimer was saying that I was a beginner, not the people on the forum.

I see a lot of new people buying these machines for retrofits --- I'd have liked to see a detailed set of steps when I took apart mine, so assume they would as well.

Obviously, this isn't a particularly useful post for anyone who is a real machinist. But I assume they'd skip as soon as they saw the machine weighs only a couple hundred lbs...

Sorry, I could not resist....

You did a beautiful job.....Thanks for sharing.

To the OP, nice job on the rebuild. Some of those parts ( what's left of the mechanical ) can still be had. If Emco does not have them then check with a company called Blue Ridge. I think they are out of PA. Emco sold off a lot of the obsolete stuff to them years ago.


SchneiderMachine

You most likely already know this but pay attention when you disconnect the plug for the tape drive. It CAN go in 180 off and blow the drive and possibly the board it's connected to.

I have an old tech doc on it somewhere. if you need me to scan and send it to you let me know.

Dave

Thanks for the offer Dave but I believe I have that tech document already. When the lathe was at work we replaced the drive back in the late ninety's
I think the new drive lasted about 3 months
Dave (the other Dave )

Originally Posted by cncmek

To the OP, nice job on the rebuild. Some of those parts ( what's left of the mechanical ) can still be had. If Emco does not have them then check with a company called Blue Ridge. I think they are out of PA. Emco sold off a lot of the obsolete stuff to them years ago.


SchneiderMachine

You most likely already know this but pay attention when you disconnect the plug for the tape drive. It CAN go in 180 off and blow the drive and possibly the board it's connected to.

I have an old tech doc on it somewhere. if you need me to scan and send it to you let me know.

Dave

coltz,
do you have the rest of the details on the retrofit that you done on this lathe. I would be interested to see what you eventualy carried out and what you used.
Jimbo

If you're going to go through all the time and expense to rebuild a machine, why not do it to a real one? That Emco is a joke. That thing is for high schools to demonstrate CNC, not make parts.