What lathe to buy?

You don't have to have a collet, you can just grind out a 3-jaw chuck to a good fit on 1.25" stock anmd you are only limited by the spindle hole. Since you are making short pieces you might look at some 3-in-one imports; you don't need the mill part but the rest might be the right size for what you want.

Seems to me that starting with a lathe would be overkill in this application. A powered drill, a cutoff saw, a collet style clamp would work nicely for the "machining" part and the plastic would not then need to rotate.

Well I'm trying to build an automatic machine. With a collet setup using air power to open an close the collet is straight forward. If there are small air powered chucks available I'd like to hear about them.

You can forget the small lathes. The spindles won't pass 1.250 stock. Nor will 2J collets hold that size either. You need at least a D1-4 spindle so a chinese 13 by 40 lathe is what you are looking for and I suggest a 6 jaw chuck. Steve

Part off first with a "MAKITA 12 INCH METAL CUTTING SAW LC1230"

Then face and drill with the 2" long workpiece in practically any 3-jaw chuck in practically any lathe.

--Winston

I don't understand the concept

First one useful thought. Old NC lathes are worthless, and might have a huge spindle bore, if you have floorspace.

Why are you starting with 12 inch pieces?

What are the accuracy requirements?

Are you turning the OD?

Give us some idea of the whole concept, perhaps we can be of more assistance

On Sat, 15 Jan 2005 17:12:26 -0500, Fred wrote: Greetings Fred, An old CNC lathe would be ideal for this job. First though, I wonder why the plastic is in 12" sections. Did you maen perhaps 12 FOOT lengths? Anyway, a CNC lathe would have a turret. You can use the turret index command to open and close a collet if the lathe doesn't already have an automatic chuck. And a bar feed can be made with a rotary union. I would be happy to discuss this with you over the phone. E-mail me and I'll sen you my number. I have modified old CNC lathes for completely autonomous operation. Only loading in new stock is required. Cheers, Eric R Snow, E T Precision Machine

Burnerd makes (made?) a collet chuck that will take up to 1-3/8" round stock and each collet has a range of 1/8". There were at least two styles of chuck, one that takes a (large) drill chuck-type key and another with a lever arm that lets one open/close the chuck while it is spinning. The latter might work for your application with some innovative engineering.

You can see an example of the collets here:

I happen to have one of the lever types for an L-00 spindle with a full collet set that is gathering dust. Email me if you think you might be interested in it.

Mike

you need a turret lathe with bar feed if you are just doing that part.

JOhn

I just pulled a Zaggar power feed drilling head, along with the Emerson VFD to operate it. Ill make you a very good deal on it. Can be mounted horizontally (usually is) and set up as a fixtured drill unit.

Gunner

"At the core of liberalism is the spoiled child - miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke

If Eric doesnt have a machine for you, Im sure I can. Btw..you want

16C collets. I can build you one or find you a suitable old CNC lathe.

All it takes are pictures of dead presidents.

Gunner

"At the core of liberalism is the spoiled child - miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke

Don't [try to] reinvent the wheel.

What you are describing is a screw machine [or automatic lather for our European friends]. With feed tubes, these can take 8 foot or longer stock eliminating much of the material handling. Brown & Sharpe and Traub are two names that come to mind for what you are doing. Given the description of the job, most likely you can get by using existing "pick-up" cams for minimal tooling costs.

Before investing in a machine and the upkeep, I would check to see if there are any screw machine shops in your area and ask them to bid on the job.

I am cross post>I need to build an automatic machine to perform a fairly simple job.

I used to do exactly this.

I worked for a company that made nylon sheaves, and rollers.

The fastest way is to bandsaw slugs out of your bar stock.

Put the slugs in a chuck and finish one side, flip over, finish the other, and bore the center.

You will need an operator to do this, but with foot long barstock, a bar feeder is pretty useless anyway.

A bandsaw can cut the stock much faster and more efficiently than a parting-off operation in a lathe.

Jim

| On Sat, 15 Jan 2005 17:12:26 -0500, Fred wrote: |

| | The job: | | | | 12" long x 1.25" diameter bars of a plastic material need to be cut | | into 2" long sections withe a hole center drilled their entire | | length.

Did you mean 12 _inch_ long bars, or 12 _foot_ bars? What kind of plastic material? What kind of tolerances? What kind of surface finishes (prettiness)? What kind of price range are we looking at?

moT

And by using soft jaws, you can set the chuck up to provide a depth stop as well, to allow facing to a precise and repeatable length if necessary.

Or -- since you mentioned the desire for a power-operated collet, I'm holding New England Brass and Tool's new catalog of Bison chucks, and they have a 16C collet chuck as a variant on their 5C collet chuck. Both mount the collet entirely outside the lathe spindle, and the 16C collets in that chuck are spec'd to handle sizes from 1/16" to

1-5/8" -- which should be big enough to handle what you need, since without the drawtube in the spindle, you can clear at least 1-3/8" in any lathe made for 5C collets.

It says that it is power actuated, but I don't see how, precisely. I would suggest that you call them (or some other Bison importer) and ask for details. Their phone number is: 781 729 7672 (if I managed to type that correctly around the cat. :-)

Good Luck, DoN.

We make a Delrin ( plastic) 1-1/4" roller with OD grove, hole on the centerline and chamfers on our CNC lathe in about 1 minute. Maybe it would be more economical to buy them from us and forget making a custom machine. We also have a fairly good source for surplus 1-1/4" Delrin. Leigh at MarMachine