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(Relatively) smaller-sized production lathe?

pmdude

Aluminum
Joined
Aug 16, 2006
Location
Florida
Hi all,

My first post here. I'm looking into the purchase of a CNC lathe to bring the machining of some components in-house. There are only a few parts, all aluminum, diameter is max 4" and length max 3", and volume is very low at about a few hundred pieces per month.

What I'm looking for is a relatively small lathe, rather than the 6,000-lb to 13,000-lb machines I see on Ebay. Also, a smaller footprint of up to 3' x 4' would be much nicer. Finally, I'd like to keep costs in the $15k range, though I could stretch a bit more if I have to. Obviously, I'd go with a used machine, but prefer a dealer so that I have some warranty, etc.

I do not know a lot about machining, so I would hire the appropriate skills to run the machine. I am willing to sacrifice on the controller and have no problem learning any primitive programming language, especially since there are just a few parts, so I will not be re-programming it regularly.

That said, I found a few machines so far that might be in my range. The best fits are the CMS GT27, Accutrace GT27, Protolab machines, some smaller Mazaks such as the QT6. Some of these are in my footprint range and weigh only 2200 lbs.

Few questions:
- For what I need to do, are my specs appropriate?
- Any other machines (brands/models) I should be looking at in this range?
- Is it reasonable to expect what I want for under $15k?
- I've tried calling CMS, but there is no answer for 2 days -- just a recording that I've reached a general delivery mailbox that is full. Even if I am buying a used machine, I'm worried about contacting them for service. Anyone know what's happening with CMS?


Thanks,
-Neil.
 
That seems to me to be a small machine footprint for the type of diameter you're talking (4"). Is it all chuck work, or is there collet work involved as well? Also, how many different operations are needed per part (i.e. turning, drilling, tapping, cut-off, etc.)?

Also, if these are standard parts and low volume, is it really worth bringing them in-house? Especially if you have to hire someone to run the machine...
 
Hi Neil:
I've looked at the CMS machines too...they appear very attractive at first glance, but I've heard some rather discouraging things about their quality from a former technician who worked for CMS (Upgrade Technologies) a number of years ago.
I've seen a few come up on Ebay in the $15000.00 range, and they all appear almost unused...I'm told that this is because many of them never worked properly even when brand new.
This makes me very nervous...much older machines with much more heavily used appearance are going in the $20,000.00 range.
I'm still looking for the ideal fit too; my needs are quite similar to yours and I still have not found an ideal machine.
The little Emco's are toys with really weird and hard to repair controls.
Rhino makes a small CNC lathe...also reputed to be a toy.
Wasino makes a little gang chucker but it has unguarded Z axis ways and is really wide and squat.
Like you, I'm looking for the right machine to drop into my field of view...any suggestions anyone???
Cheers

Marcus
 
I'm with applied on this one. 4" dia is not your typical gang-lathe size.
If you do want gang though, Viper and Kia makes larger frame machines. Kia having a slight advantage with the 18" X-travel to give a little more headroom.
Price is reasonable, I think somewhere $45K or so.
Viper does come with the barfeeder < not optional >, but it won't barfeed 4" anyway.

IMHO, a slant bed machine with turret will be a better option. In the $15K pricerange though, you're likely be kissin' some frogs.
 
If youreally are sold on the small gang tooler thing, don't forget the little GT27 Hardinge
Very nice machien and can be had for a good price.
 
Thanks for the replies.

Appliedproto -- From what I understand of collets, they're really just a special-size chuck ... no jaws, but designed for a specific-sized part. My intention is to use a chuck initially, but perhaps get a collet later. Raw material is aluminum tubing. Largest part is 3.5" dia, mostly 2.5" dia and 99% of parts are about 1" long. But I'm being a bit conservative just in case, and thinking that if I mount a 6" long piece of tubing on there, I could make 5 or so parts and then chuck another piece of tubing on. No other operations are required.

I need to cut on the outside and the inside, and if there is a way to mount two indexable inserts (one facing outwards and one inwards) on one tool bit, then I wouldn't need even need to change tools. Since it it tubing, I could use the same bits to part the piece off, and I'm assuming that if I part from the inside, then the tool will hold the part. Lots of assumptions here, I know.

One of the big motivators to bringing it in-house is that with low volumes, we're getting screwed around by shops a lot. They deal with our stuff when they get time and sometimes this drags on for several months. Can't run a business with unreliable supply. But to make it viable, I would need to keep it around $15k-ish. I expect, from my ballpark calcs, that I'd need an operator only once a week or so, and that might be me for now. I have no problem getting trained, etc. Over time I expect volume to go up, so I don't mind investing a bit now.

Implmex -- I understand that those machines are "training" lathes and not to be used for production, even though I feel that my volume is low enough that it may get used less than some training facilities. Rhino quoted me ~$28k for the ST8 (new). Also, Knuth has a lower-end CNC machine that looks like an engine lathe with an auto tool changer and CNC controller built in. It was about $16k IIRC (new). But again, classified as a training lathe.

SeymourDumore & PBMW -- no, it does not have to be a gang machine. Turret should be fine, and I possibly won't even have to change tools (see above).

I see older/larger machines on ebay going for even $10k or less, so I was assuming I could get something similar from a dealer for a bit more, but with some support and brief warranty.

Another option I'd really like to have is if a local shop would let me use their machine for one day each weekend and I'd pay them per hour or something. But that's not likely to happen anytime soon I'm guessing.

Thanks,
-Neil.
 
BTW, I'm seeing "GT27" used by different manufacturers -- is there a special meaning to this? Or is this some base lathe that has been modified by different manufacturers?
 
pmdude

Yes, collets are "like" chucks, but they're only "like" chucks.
For starters, not many of them come in 3.5" size.
You can bore a soft clutch collet to that size, but hanging out 6" from those is flirting with disaster.

Sounds like your needs are pretty darn simple, so check out some toolroom-type lathes. there are a few manufacturers, Haas, Romi, Trak etc. See if they have the ability to be used as a gang lathe.
The Haas TL-s can be used and programmed that way right out of the box, by removing the toolpost and mount a gang tooling block with the bars sticking out side by side. US Shop tools have standard tooling blocks you can use off the shelf.
Again, as long as the control lets you program as a gang, one of those machines with the supplied 8 or 10" chucks would be a much better choice.
 
pmdude

Yes, collets are "like" chucks, but they're only "like" chucks.
For starters, not many of them come in 3.5" size.
You can bore a soft clutch collet to that size, but hanging out 6" from those is flirting with disaster.

Sounds like your needs are pretty darn simple, so check out some toolroom-type lathes. there are a few manufacturers, Haas, Romi, Trak etc. See if they have the ability to be used as a gang lathe.
The Haas TL-s can be used and programmed that way right out of the box, by removing the toolpost and mount a gang tooling block with the bars sticking out side by side. US Shop tools have standard tooling blocks you can use off the shelf.
Again, as long as the control lets you program as a gang, one of those machines with the supplied 8 or 10" chucks would be a much better choice.
 
Neil,

I never like to discourage anyone from machining, or from purchasing machine tools...but with roughly a $15K budget, I think you can get a machine for that, but when it's all said and done you can easily double that budgeted amount (rigging, electrical, tooling, repairs, downtime, learning curve, etc.). Especially if you're going in green to the field. Now my thinking is, $30K can get you quite a bit of contract machine parts. I'd suggest finding yourself a better shop.

But, if you are on the path to your own machine, I'd consider a Mori-Seiki SL-2 with a Fanuc or a Yasnac control. They are a bulletproof machine, but the machine and the control are going to be about 20-25 years old. You can get one for about $10-15K. A local shop I deal with has 3 of them from 1981, and they still very dependable and deadnutz accurate.
 
Collets are not important to me, so I'll stick with chucks.

I was factoring $15k for the machine and allowing another $5k for shipping (~$1k), setup (?), tooling (minimal) and some basic training. The rest would be operational costs. Only thing I haven't factored in yet is a 3-phase converter since I'm not sure if I'll need one.

Bigger question now -- any opinions on a 1998 Upgrade Technologies Accuturn GT27? Says max 5" chuck, 4500rpm, Gang tool. Fagor control. Is it worth $15k? It's only 2200lbs, and approx 3' x 5' footprint.

Thanks,
-Neil
 
2200lbs? That's less than a Bridgeport. Sort of the old engine adage "no replacement for displacement", well in machine tools there's no replacement to weight.

Here's a Mori-Seiki SL-0 on ebay. Pretty small and cute (you'd have to see if anyone has experience with one in the forum).

Mori-Seiki SL-O

This is the machine I have, and I run gang tooling on. It's a good machine, very easy to operate and program(except no real low-end balls), but if you're in aluminum, then you should be fine.

ProtoTRAK 1540
 
Well there is intercooled forced induction on a well-ribbed aluminum block with a main girdle... :)

Okay, back to reality...
That prototrak is well out of my budget, but I've had that SL-0 saved for some time and spoke with the company selling it. Wasn't sure if it was too old to be reliable though, so never did anything about it. I understand that Mori-Seiki's are very good machines though.
 
Have you checked out the new Haas Small CNC Lathe GT10 they start at about $24,000 and thats new. If you don't know alot about machining the dealer could be a lot of help getting you going.
 
Maybe not an issue, but if concentricity is an important factor you'll need to be real careful about chucking tubing in a CNC. Power Chucks can really emit a lot of force even at the lowwest settings. Tubing not always being round to start with and gets conformed to jaws under presure, you machine the part perfect, then release and they spring back.

15 is doable, but keep in mind you'll have a larger learning curve on the older less user friendly machines. Repairs on older machines can be real pricey, driving that bargain price up in short time.
 
Do you really need a CNC for this job? A _good_ manual lathe with a stops on the bed would probably be almost as fast. Chuck material, double tool as he suggested, bore/turn as deep as your bars will allow, Then use the stop rod set up for each part off distance and whack em off. Especially if you made a tool holder that had the cut off tool built into it. Although not a _good_ lathe, an Emco with the digital readout would work fine for this. Course, you have a bigger mess to clean up...but..cheap.
 
Oh my god, this could be an excuse for you to buy a mighty W+S turret lathe. Probably not the image you had in mind, but as pointed out above it would probably do the job.

Paul T.
 








 
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