Emco Compact6 CNC lathe.

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dieselpilot

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The Compact 6 CNC project is alive again. Today, I stripped the spindle and while the bearings are in decent shape, there was a lot or debris inside the spindle housing. I may replace the bearings while I have it apart, but I still have to pull the outer races from the casting.

Greg
 

DICKEYBIRD

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Greg I'm glad you've found the time to get back on the Emco & the time to document it as well! I really like reading you posts. Please keep it going. What CAM do you plan to use?

Selfish guy that I am, I'm sad you're going with LinuxCNC as I chose Mach3 for my ORAC retrofit and would've learned a ton from you as you slapped Mach3 into shape.;) It's all a struggle for me.

I have mine working but it's still early days. At the moment I'm hooking up a tach-generator as I have a 3/4 hp Baldor DC motor with a KBMM-125R controller (does reversing & dynamic braking) KB says with a 7V/1000 rpm tach-gen I'll get 1% speed control over a 50:1 speed range. I'm also struggling trying to get my head around setting up the tool table in Mach. I have no ATC but will have 2 QCTP's and hope to be able to manually switch between 6 or 8 tools without having to re-reference each one.

I've bookmarked your site am really looking forward to see your progress!:)
 

dieselpilot

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I did tear down the spindle this afternoon. I'm glad I did as there was crap in there and the nose bearing probably wouldn't have made it much longer before failing.

CAM for lathe? Probably none, unless I get some complex parts to run. My old man has been hand coding lathes for 25 years. I do actually own a license for bob(crap)cad with lathe, but I've not used it. I happen to bump into a guy at NAMES last year who did a Compact5 CNC with a toolchanger who is local, so that will be a great help. I chose an AC induction motor with VFD as mentioned above. I do think this will work OK, but I don't know how deceleration will turn out. The AB VFD on my Clausing will stumble if I lower the speed too quickly. I haven't looked into the spindle encoder very closely yet. I do intend to do better than just one pulse per rev.

I did also track down a 4" 3 jaw Microcentric air chuck and tube for a grand total of 120USD. So, I'm glad I didn't rush and order that TOS chuck. Ebay yields great finds if you're patient.

I still have the bed and carriage of what was a central machinery 3 in 1, that was going to be my CNC lathe project. I was planning on QCTP for that. I still haven't figured out how to do manual tool change on the mill with LinuxCNC (actually still running the old EMC2.2xx). I just make separate programs. I did see a nice manual tool change program for Mach on youtube recently. I'll have to revisit the Linux CNC forums, it would save me some time. Tool table in LinuxCNC seems easy and I use it for radius compensation for thread milling.

It seems like tooling alone will be a fortune. I'm buying external holders when I find them cheap enough, boring bars seem expensive and lefties uncommon on Ebay, and have 3 ER16 collet holders already.

BTW, Some of the first parts I hope to run will be Cox related.

Greg
 

dieselpilot

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I hope I remember how all the sheet metal goes together. I didn't expect to let this sit for a whole year!
 

DICKEYBIRD

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BTW, Some of the first parts I hope to run will be Cox related.
Ahh, my sordid past comes up again.:)

Funny, I got my 1st machine tool in 2005 and the Cox engine/model airplane obsession fizzled out in less than 6 months. I got the lathe to make a few Cox widgets but never did. I still have it all stashed away in boxes. My oldest grandson is getting old enough now that I should drag out some stuff & teach him to fly before long.

On the CAM side I've been using the Mach wizards for simple stuff but recently got really lucky and one of the Mach support forum gurus made me a killer deal on Dolphin v10 with the lathe dongle. It's very powerful and will do all I'll ever need. The Mach post processor is going to need some tweaking to play nice with my lathe once I get through screwing around with it. Fortunately, the seller will help with that as there's no way I can do it.

It'll be really slick for you being able to use a spindle encoder with LinuxCNC when you start threading. As you know, I'm stuck with 1 pulse per rev with Mach. That's why I'm adding the tach generator to help stabilize the spindle speed. I'm not even going to try threading until that's working.
 

dieselpilot

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Whether or not you'll be able to get away without hand coding depends on the precision required of the parts and the accuracy of the machine. My father gets jobs with CAM generated programs from the front office where the ±.0002" tolerance is much less than the bow worn into the ways and the backlash(after compensation) on the 15 year old lathe he runs. The CAM software can't account for the machine character. They program theoretical feeds to keep production high, but reality is often different. So he has to tweak the code by hand to take into account tapers and such to make the parts to print. The company doesn't keep up the equipment as much as you'd they they should to produce parts to the tolerance they quote for customers. In our little machines we'll have to settle for whatever the machine makes as I doubt the resolution will be there to fix a taper of a few tenths. I use my machines for prototyping work so I may be more critical. I'm sure maintaining spindle speed will improve threads in Mach. As you can see from my site I mess with rc engines quite a bit. Going to fly my diesel four stroke this morning.

The spindle bearings turn out to be standard off the shelf, even used as wheels bearing in some cars.

Greg
 
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DICKEYBIRD

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As you can see from my site I mess with rc engines quite a bit.
Oh yeah, I've been lurking & admiring your work for years. Very enlightening & interesting stuff you do.:) I have some r/c day-dreams I hope to get around to at some point.

I've done some code tweaks as well on my other little cobbled up CNC lathe/mill and been known to "adjust" things with a file, emery cloth or whatever's necessary to make things fit.;)
 

kvom

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When I was learning lathe programming using a Haas, we could use the G7x canned procedures, so hand programming was relatively simple. mach3 turn doesn't support these canned procedures, so multi-pass roughing isn't easy to code. I've used CamBam for lathe for some simple parts. However, it supports only turning.
 

DICKEYBIRD

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mach3 turn doesn't support these canned procedures, so multi-pass roughing isn't easy to code.
Hmmm, have you used the wizards lately? Maybe they've changed them?? I just ran a couple simple parts with a turned down spigot on the end of a shaft with a blended fillet and it worked great. You tell it a finishing cut depth, roughing depth, fillet radius (and of course X/Y start/end coordinates and the other required info) press enter and whammo, instant G-code that rough cuts down to the finish point, switches feedrate and makes the finish cut beautifully. I've used several other wizards in the past that worked well too.
 

kvom

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Never tried any wizards. Thanks for the heads-up.
 

DICKEYBIRD

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You're welcome.

Mach comes with a quite a few useful lathe wizards and there are some more available free on the forum. NFS has even more but they get $50 for a license.
 

dieselpilot

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Some careful searching in Ebay netted bearings with slightly better precision than standard at a very fair price. I'll move on to cleaning the turret or carriage while I wait for bearings.

Greg
 

dieselpilot

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All the parts are clean and waiting to be reassembled. I purchased new bearings for the ball screws. I put myself in a corner by making a mistake during reassembly of the spindle. There is a part which needed to be put on the spindle before the bearing. Needless to say, I got ahead of myself and remembered the part just after the bearing cooled to the point I couldn't move it. The bearing sits near a shoulder and there is only a 0.8mm gap. I borrowed a bearing splitter which was too small. I tried to rent a bigger one, but the rental places didn't have them(they stopped offering them). I took it to transmission shop and nothing. Finally, I made something last week and got the bearing off, but have been busy with work. Slowly but surely.

That's nice work on that conversion. I was looking at something else he did recently.

Greg
 

DICKEYBIRD

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You gotta get that puppy up & running Greg so you can play with it!

I've made some more progress lately on my ORAC retro & cut my 1st CNC threads today.;D 16x1.5 mm in nasty hardware store CRS and the die screwed right on with hardly any effort on the 1st try. What a feeling!

Gotta get some 'real' threading inserts and a holder when I get some hobby cash but it feels great to watch the magic happen with just a cheap-o brazed tool. Of course if memory serves you've done thread milling so it wouldn't be as exciting to you to do CNC lathe threading.
 

dieselpilot

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This project isn't dead yet. I've been very busy with work and recovering from hernia surgery. I really should get all the enclosure parts picked up off the garage floor and so I can put the other car in. I also found a small piece broken off of the bearing cover on the spindle housing. It's part of the weep slot of the labyrinth seal. It's probably not a big deal, but I do have to decide if I'll make another before reassembly. Doing it later means a complete tear down to where it is now.

Greg
 

dieselpilot

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I guess I should post an update. I'm in the process of reassembling. The spindle is done and mounted. The new spindle motor is mounted. Turret is disassembled, and partly cleaned. I'm trying to decide what to do about the putrid yellow. I'm not sure if a rattle can paint will hold up to coolants. I might check with a place in town to see what it would cost to blast and paint the sheet metal. Some photos are on my Emco Compact 6 page.
 

dieselpilot

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Progress has been slow. I have cleaned and reballed the ball screws and reassembled the Z axis. I also made a print for the "old style" turret plate (disc) for somebody who had a machine without one.

 

rcfreak177

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I'm trying to decide what to do about the putrid yellow. I'm not sure if a rattle can paint will hold up to coolants. I might check with a place in town to see what it would cost to blast and paint the sheet metal.
I went with sandblasting and powder coating, came up like new and cheap as well. I think from memory it 100 bucks for the lot.



 
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