BRINGING CHARLEY BACK TO LIFE

[ozzie34231]

I bought a knee mill, ,,,what I think is a big mill for me as a hobby machinist. It's 4000 lbs, travels of 29+", 16", and 6". I named it, Charley.
Charley began life as a CNC machine back in the mid 1970's, but somewhere along the way, it was stripped of all its electronics but for the motor contactors. It has a 3 HP, 3 phase motor, variable speed pulley system. Charley has a 4 3/8" quill, (not a typo). It has an automatic oiler system, and a built in coolant system.
The used machine dealer I bought it from thinks it was built in Japan for a NY company, Autonumerics, which then added the electronics. It was sold under a name registered in 1969 Positool. An Atlanta company, Allison Machinery, sold the unit new, but the owner of that company remembers nothing about it, although he remembers handling the line. I have searched for many hours without finding anything about it.
My hobby for about the past ten years has been CNC, as applied to a 3-in-1 Shoptask, and then recently a 1440 lathe I converted. The only path I know well is Mach 3, Geckos, servos, (although I had a little experience with steppers, EMC, and other software in the early days).


So the task I've set is to make Charley live again as a CNC machine, and I'll do it with almost no money.

Jerry "Ozzie" Pryor
Old Curmudgeon

[Al_The_Man]

It looks to me just like an Excello Ram Turret XLO602 or knock off?
Looking at the handwheels there seems no trace of it ever being CNC? Is there ball screws on it?
Al.

[ozzie34231]

Hi Al,
Yes, it has ball screws, and I can't detect any backlash in the x and y, haven't tested in Z. I suspect that when I get servos running I'll find a little but now I expect lass than a thou.
You can't see in the pictures I sent but around each of the X and Y handles there is bare metal and four screw holes; some sort of servo mount.
The Z has a hole where a hand feed would have gone, but if you look in, there's no rack grooves in the quill. The Z has/had a timing belt pulley and no other way to move it.
I suspect the whole knee was moved to use it manually. The knee moves easily and it has graduation rings.
Can you tell me more about the machine you refer to.

Ozzie

[ozzie34231]

Again Al,
Just Googled that machine and it looks a lot different. Charley's head doesn't tilt or nod and I can't make the ram even swivel.

Ozzie.

[Al_The_Man]

The Ram head moves in and out though, right?
At least it look as though it does.
Most of the XLO's CNC'd the quill, the knee can bring a few problems.
Al.

[ozzie34231]

Yes the ram moves.
I didn't mean the knee was ever CNC, just that I think when it was modified to be a manual machine, that was the only way to obtain Z movement.

Ozzie

[ozzie34231]

I've done some of the work before I decided to do this thread, therefore the number of pictures from the early work is small. I'll describe the work.
I began by removing all the little plates to see what I could see. There are two air cylinders on Charley, one shifts between back gear and straight drive, the other operates a spindle brake.
The belt cavity was full of belt shreds and dust. The belt was badly deteriorated, cracked and frayed at the edges.
I started from the top end.
I cut the belt out, vacuumed much of the crap out and started dis-assembly. I lifted the motor out with a slightly modified engine hoist Then I coaxed the spindle pulley system out with a pair of screw drivers.
I cleaned all that. The bearings seemed fine. I was able to read the belt number and ordered a replacement.
The belt drive housing was still filthy and under it, in the back gear housing I could see a retaining ring floating on top of the bearing it should be holding. I took the housing off to further clean and got to the retainer.
The brake system revealed, I could see it was a system similar to drum brakes on a car.
The large back gear is made of some sort of plastic, maybe Delrin. It's damaged in a couple places; from heat I think. I took a couple pictures, measured it and put it back in. I know the machine runs in back gear; just don't know if it has power.
You may know that very recently Art Fenherty has created software to cut nearly perfect gears with a straight mill and a 4 axis cnc setup, "Gearotic".
On that discussion group I was helped to identify the gear parameters, and at some point I'll make one for the cost of a piece of Delrin.

Ozzie

[ozzie34231]

Here are pictures of the two air cylinders.

I'd been asking on the Mach 3 Yahoo group for some leads on finding cheap relays, operating from the 5v parallel breakout board signal and switching 115 v AC. For some reason I couldn't find them searching Mouser and a couple other sites. Finally someone steered me to relays that cost $1.21 and I ordered 10 of them. These will operate the 115V to 3phase contactors for the spindle motor, coolant pump, and whatever might come up. One come-up is I found new surplus 115v air switches that will control these two air cylinders. they come with no info so I'll need to figure out the porting.
Ozzie

[ozzie34231]

When the belt arrived I had no idea how to install it.
I thought that if I could take the spindle pulley apart It would go in fairly easily as I lowered the motor and its pulley. The problem is I could not figure out how to get it apart.
I put the belt on the expanded spindle pulley and tried to work it on the motor pulley. I struggle a few hours a day for 3 days; nope, won't go. I began to think I had the wrong belt.
I decided the motor pulley had to be expanded also, but how?
I contacted the dealer, and he said that if I remove the bearing I'll see two holes and by putting long screws in there I'd be able to compress the spring.
Okay, but the holes turned out not to be there. Now what? No answer from the dealer.
I pondered for several days during that time I found an inexpensive 3 phase motor to use building a a rotary converter; $70, half of which was shipping.

The solution to the belt problem had to be taking the motor pulley apart. I knew there was big time power in that compressed spring. I decided to take the bottom motor bearing housing off, and compress the spring with a plate I'd make using the same profile as the housing piece but with a hole in it. I'd pull it tight, remove the retainer clip and slowly decompress the spring by lowering each of the three nuts.
I ordered some M8 1.25 threaded rod from McMaster. I put the housing piece in the vise on the Shoptask, and a pointed pin in the spindle. Then using Mach 3 "Copy Cat" wizard I created the profile I needed to mill a plate from 1/8" plate.
I hope that explanation along with the pictures makes it clear what I did.
I'd still like to know how it should be done.
Any way the belt is in and appears to be the correct one.

Ozzie

[ozzie34231]

When the machine arrived there was this piece of rubber in the electrical box.
It has occurred to me that maybe this is intended to facilitate belt installation.
If the motor pulley were expanded, maybe this would wrap around the small diameter and hold it there. But how would you get it in there? If that's not it, what is this thing?
Ozzie

[Al_The_Man]

The spindle brake cylinder arrangement looks identical to the one on the Excello, I put a 3 way 2 posn solenoid valve on it that turn off automatically when the spindle is energized, I also have manual override switch.
Al.

[ozzie34231]

Good idea Al.
There needs to be a safeguard against having the spindle and brake on at the same time. I can't help thinking that some of the horrendous belt disintegration on this machine happened when the spindle was started with the brake still on.
What air pressure does your brake cylinder use?

Ozzie