[Paul G]

Hi i have the opportunity to get a late 70's AN-S CNC. It has a dufunc Bandit controller with missing boards - as the repair person took the boards to fix and never returned - end of using it.

Allegedly mechanical condition is good but i can't verify as its not under power. It was owned by a sheetmetal shop that used it 10 xs since 1997 and previously by a tool

Plan is to get this and retrofit with Gecko drives, mainboard, power supply and run off of PC.

Being completely new to cnc machining and machines, and this will be my hobbiest CNC machine, do you think it is worth the endeaver? I can get it for $600 + $200 cost to trailer it back myself and i figure it may cost $1200 to retrofit if i can not use the existing servos /encoders. But i would hope i can use the existing servos but not sure exactly what they are. This assumes the machine is fine mechanically. Is there any thing i can verify mechanically while not under power?

Thanks in advance,

Paul

[123CNC]

I would try to talk him down further, say $400. Aside from a very determined guy to breathe life back into it, it is basically scrap. Not only that, it is a very heavy piece of scrap. The AN-S tips the scales at close to 5,000 lbs. Much heavier than it's little brother or Bridgeport Series I or clones (typically closer to 3,000 lbs.) You'll find this a bear to move around in comparison. They are very heavy duty for a knee mill with boxed ways.


You can pull the spring covers back on the x and y-screws to inspect, and remove the front cover plate to see the z ball screw. Being that they essentially were manual mills converted to CNC, you can fairly easily grab the x and y dials and manually move the table and saddle to check for smoothness, but before you do a good idea to check the manual way oil pump on the left side of the knee. Inspect it before pumping, if it has sat any length of time, it may have dried up like a varnish or shellac. If it still looks good, pump it slowly one fulll stroke and check for leaks at unions or length of tubing. It's not unheard of to get a leak under the table in the saddle, but you won't know it because the casting can hold a lot of oil before you ever see it. Checking the conditions of the ways though should quickly reveal if they ran dry. If it has sat a really long time, you may need to loosen the gibs and try to shoot some oil in there and manually push the table and or saddle to see if they will budge. If any axis is frozen solid or the screws are rough or worn, you should walk away or ask them how much they will pay you to haul it off.


These machines are super well built, as they say 'like a tank.' The only small downside is the limted 5 or 6 inches of z travel, a bed-mill thus becomes more desirable. The AN-S usually has a 5-hp motor, compared to the 3hp or smaller on Bridegport series 1 size mills. This is good and bad, the sub-3 hp motors are easier to get more affordable single to three phase VFD's, the prices quickly climb up from there. I have heard of a few having problems with the back gear in the head, don't remember precisely if gear itself or related bearings, but something to be aware of. It may be hard to find these parts any more, it's not like a Bridgeport or clone. If there was a problem, you could work around somethings, like maybe going direct drive if you go the vfd route.


It looks to have brushed dc servos with resolvers, you'll have a few options to try and retain the axis motors. MESA electronics and I think Pico make boards to try and retain the resolvers to adapt to more modern drives. Or you can scrap the resolver and get encoders. A multitude of drive options, suggest looking at Gecko Drives, Keling (Aka automation technologies in Illinois), Dudong, or AMC or others off Fleabay. The Gecko's will be slightly undersized for these, but will work.


I believe I still have a large pile of Bandit stepper boards lying around, only think I ever had one servo bandit (not sure if still have any of it, but you will be welcomed to it, if not too far from the Sacramento area).


The pictures make it look in fair condition, but you never know if it was only an electronics failure or a hardware followed by electronics error. Best of luck, and share more pics if you decide to jump.


PS A guy in Turlock has 3 AN-S on Craigslist thinking he'll get more than $5,000 each. He will be darn lucky to get $1,000 for any one. They will eventually go to scrap or be available for parts, or some very very determined guy might want to try and breathe new life into one of them. Unfortunately, IMHO I think you or anyone would be better off with a new Tormach or Novakon if you are willing to put $5,000 towards a mill. Of course $15,000 you might as well buy one brand new working machine, e.g. Tormach or Novakon, or seriously looking at used VMCs.

[underthetire]

Looks like the servos are missing the brushes and caps as well. Not sure if you can still get electrocraft parts or not. I do remember the last vari head belt I sold back in the day was well over 1000.00 for a belt! Shizuoka sold the iron, then 3rd parties would put controls on them, that's why you saw different controls on them. Good iron on those machines!

[Paul G]

Thanks 123CNC and Undertire - that was a lot of helpful information.

My budget for a mill is really under $3k - just all i can get by with for a hobby mill and i would like CNC for sure.

I'll check the items - wrt lead screws i guess i'm looking at backlash - and if i remember right from reading - this should be less than about 0.001" for ball screws or ????

I'll pull the spring covers back - assuming that is the the picture of the coil looking cover - i assumb worn srews will be relatively apparent - not uniform looking.

WRT the servos - they do have brushes and caps - the pictures are just deceptive. But i do need an intermediate card to save the existing servos to work with Geckos for sure.

If i were to buy new servos for use with Gecko drives - what would you recommend and how much might they cost, keeping in mind I am not looking for the fastest feed rates as i'll have nothing to do longer!

One thing i do like about it - is it has vari speed spindle and solid machine - which seems like a lot of CNC machine compared to a manual mill that I may pay $3k for - but then not be able to do nearly as much. Just my current reasoning. My friend has an ST-N with steppers, he did retrofit it with new Gecko drives and board and the machine runs quite amazingly nice.

I will go and look at it again this Thursday.

Thanks,

Paul