Looking to buy my first CNC setup. Thoughts on this Partner III / Cent IV setup?

[motoguy]

I'm looking to put my first CNC machine in the garage. A friend's boss has a Partner III for sale. The owner of the mill is replacing it with a Hurco Eagle. This owner is a private "tinker in my garage" owner, and the machine has not ran production. According to the information I've been given:

has drip feed for control
10 hours on rebuilt head
only cut plastic before the current owner
needs new conduit for the umbilical

The owner is an instructor at a university, and rebuilds / works on CNC equipment as a hobby. In a prior life he was a CNC maintenance tech, so he has a lot of connections for parts, rebuilds, piles of misc boards / controllers, etc. He's offered to help me set up a 4th axis on the unit, assist with any troubleshooting, etc.

He claims the head on the unit was rebuilt about 40 hours ago. He said it runs great, and will hold .0005" tolerance. He's also offered to help build a RPC to run this machine (as well as a manual mill), offered to help me rebuild a used Lagun manual mill, etc.

The price I've been given for the above machine is $2000. The unit has the Centurion IV controller. He claims he's never used the drip feed, but that the hardware is included. This is important, as I plan on using a CAD/CAM software setup to generate G-code. He also has copies of the parameters for the machine, and said he's replaced the OEM memory battery with a "4-D cell unit, so you shouldn't have to worry about that for a while".

My plan is to use the machine on plastic, possibly wood, aluminum, and steel. My anticipated usage would fit on the traditional 9x42 table, but as always, bigger is better. This will be a prototyping / one-off machine in my shop, not a production rig. I would like to be able to make some molds for injection molded plastics, as well as create parts for my motorcycles, guns, RC aircraft, and whatever else blows up my skirt. I plan on generating my G-code with MasterCam, which I have access to at school.

What do you all think of this machine, at this price point? Again, this will be my first CNC. I -had- been shopping the Tormach / Novakon units, but I decided I'd rather go with a used servo controlled machine, vs the stepper units.

This unit puts me in kind of an interesting spot in regards to my first CNC purchase. It's an old unit, with limited Z travel, and an old controller. Those are negatives. On the flip side, it's been maintained by someone actually competent in the area, assured to be in "excellent" condition, and moreover, the seller has offered post-sale support for maintenance, upkeep, and expansion (see 4th-axis offer, above). Given my current (entry level) knowledge, it would seem that the maintenance / support / "will travel to your house some weekend, and we can ride motorcycles / work on CNC's" offer would be worth a significant $$ amount, by itself. Any other used CNC in this price point is likely (IMO) to need rebuilt / work, and I would expect it to be 100% "my problem" once I haul it away.

It seems this isn't the ideal machine, but that it may be an excellent opportunity to make chips NOW (vs stumbling through a 3-year self-taught rebuild), as well as having access to a hardware "knowledge base" during my initial (steep) learning curve. Thoughts?

[awerby]

and ended up gutting out the Centurion IV control and servo motors, replacing it all with something more modern. It did work (sort-of) when I got it, but there was no way it would execute a G-code program written by a modern CAM system. We tried to set up drip-feeding, but the ancient computer just wasn't up to it (I think it had about 4 mb of RAM). Also, every time I'd punch a button, I'd hear the sound of ancient plastic crumbling.

If the seller says it will run your programs, why not show up with one and see how that works before plunking down the cash? Like the man said - "Trust, but verify"...

That said, if you are up for a retrofit project, you could do a lot worse than a solid piece of old iron like that to start with. The rebuilt head is a definite plus (we're still looking at doing that to our Beast) and if the ballscrews are in good shape they're worth the price of admission right there. (But don't tell the seller that - he's probably more interested in getting his floor space back than in getting top dollar for this machine...) And like you say, having his help with all this is worth a lot.

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[motoguy]

The seller and I have both been pretty busy lately, but I think we're looking at actually finalizing at the end of June.

I thought I'd ask again for any input regarding this unit / purchase, or if anyone has any suggestions on a significantly better machine for 2, maybe 3x the cost (up to $6kish). I wouldn't mind spending more on a significantly better machine. However, if this one falls in the "good value" category, I'll just plan on picking it up.

[moldcore]

I agree with the previous poster. You can do a lot better for 6K that’s for sure but 2K may be OK if you can make it run but an expensive boat anchor if not. I’m afraid you’ll have to gut and replace the whole thing to make it productive even if it runs. If you want a hobby machine then just maybe it will do but it looks like it may take up a lot of floor space for what it does. If you want a knee mill then find a used Trax or something newer.

I have a fully enclosed 1995 Partner 1 machine with 12 position tool changer, 6,000 RPM, and Centurion 5 controller that I once tried to sell for 6k and had no takers. The market is flooded with used machines right now so I’d shop around some more.

[motoguy]

I don't mind paying more for a "better" machine. However, I'm looking for one...now. We've got a baby arriving at the end of October, so I need to have everything done and set up by then...otherwise, who knows when / if it'll happen.

Anyone know of a "good deal" on a running / solid machine that's available right now?

If I decided to upgrade this one, what would be a price to expect? I spoke with the seller again today, and he said he'd help me find a 4th axis, thinks he has a spare controller board, etc.

[moldcore]

If you get a forth axis, how are you going to program it? Not with that old controller is my guess. To upgrade that old Partner it will be at least 3 grand for controller, servo drives, screws, etc. Plus your time and labor. You may find some used controllers and parts on eBay and cut that down in half. I’ve never rebuilt one, these estimates are from what If read here and other forums. So take for what it is, only a guess.

My Partner 1 is still available and runs fine. It’s very similar to this one only a year or 2 older: MILLTRONICS VM16 CNC VERTICAL MACHINING - SOLD - - CNCzone.com-Classifieds Buy and Selling

I once thought of upgrading the controller and got estimates of about 2K, but decided it was fine the way it is. A little slow for 3D mold work but great for 2 ½ axis. May need a new monitor pretty soon as this one is stating to flicker and loose color. These can be replaced fairly easily.

[motoguy]

moldcore, can you send me a PM or e-mail with the info on your unit?

Current owner of the mill in my OP thinks the board will support a 4th axis, but he isn't certain. He said he'll check on that for me. He said the head has <150 hours since rebuild.

I'll point out that I plan on using CAD / CAM for design and G-code creation. I need to have something that can communicate with a computer, or take input from a computer. I don't know much about the drip feed aspect of the mill in the OP.

[awerby]

when G-code was all written by hand, objects were simpler and the code for cutting them out was a lot more concise and efficient. One command, like a G02 (make a circle) would keep the machine working for a while. With code like that, "drip-feeding" can work, even with a severely constrained CPU and memory. Modern CAD/CAM software, on the other hand, breaks down a curve or surface to be cut into thousands (if not millions) of tiny moves. That old NC system will have a hard time keeping up at any reasonable speed.

I also doubt that you'll be able to integrate a 4th axis into that old control system, and also doubt it would be worth the effort. Think of that machine as a nice heavy frame to mount a new CNC control system on, that you didn't have to build from scratch. If you're not ready to do that, then don't get it - it's never going to be able to deal efficiently with modern machine-generated code, especially for 4 axes. Keep an eye open for something a lot newer.

Andrew Werby
ComputerSculpture.com &mdash; Home Page for Discount Hardware & Software

[Wcarmn]

Milltronics builds good machines. I have several. I would tell you not to expect very much support from Milltronics on this item. My experience with their support of older machines has not been great. finding replacement parts for the cnc portion of this machine may proove difficult.

However, I would tell you that if the control is working, you will probably not need to use a cadcam system to generate code. The Milltronics control is very capable and user friendly. The conversational portion of it is unbeatable.

No offense to anyone, but to me this is a $750-$1250 machine, based only upon the high probability that once the control has a problem....you will need to pay up to make it usable....just my opinion.

[motoguy]

Thanks for the continued input, guys. I must admit, the feedback I'm receiving here has me wondering if this is really the route I want to go.

[moldcore]

Originally Posted by motoguy moldcore, can you send me a PM or e-mail with the info on your unit?

Motoguy,

I’ve sent you three PMs with no response.

[Ben Colby]

The iron, ballscrews and a rebuilt head are worth more than 2K. A rebuilt head is worth that. I would buy it in a heart beat. I've owned a Centurion IV for over a decade and it's
been a very reliable machine. As long as your rigging situation isn't difficult? ie moving into and out of your shop space, I think it's a no brainer for your "first machine". The price is right, your not going to get a running, well maintained full size CNC mill for less money.
If it fails down the road, or you lose interest etc etc. you haven't wasted much money.
I mainly cut 303, 316 stainless and aluminum on my Centurion IV and no it doesn't do it
as well as Mazaks, Kitamura's and Mori Seiki's I've run but it does it and it holds half a thou day in a day out. It's not the best CNC I now own, but it was the first one I bought
and it has paid for itself and allowed me to purchase better CNC machining centers.