Author Topic: Do I need a new lathe?  (Read 13925 times)

Offline Mosey

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Do I need a new lathe?
« on: January 17, 2013, 03:51:24 PM »
Well, since I am making many tiny bits these days, and I don't like my Derbyshire 750 for that, I need a new small lathe, don't I?
The Derbyshire is very nice, but it is a jewelers lathe so the saddle doesn't travel on the ways, except for unlock, move, relock.
What is out there in very small size that has high precision and a traveling cross-slide/compound?
Love to find something Swiss to keep the F1 company, maybe Habegger, Schaublin 70 mm, etc. Can't break the bank though.
Cowells? Sherline?( not precise enough) Unimat? No.
I definitely want precision or there is no point in switching from Derbyshire, which is fully accessorized.

Offline b.lindsey

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Re: Do I need a new lathe?
« Reply #1 on: January 17, 2013, 04:06:59 PM »
What kind of precision are you looking for Mosey?

Bill

Offline Mosey

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Re: Do I need a new lathe?
« Reply #2 on: January 17, 2013, 04:26:13 PM »
Not watchmaker, but sub-thousandths. Equal to my South Bend or better.
Today I'm making teflon buttons for my wrist pins, so I need diameter to fit snugly in wrist pin bore, that king of precision. A couple of tens.

Online steamer

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Re: Do I need a new lathe?
« Reply #3 on: January 17, 2013, 04:54:34 PM »
Mosey,

If your sub 1/4" diameter...and not made out of tungsten.....I'd stick with the Derbyshire.

The spindle is really key...next is the cross slide.

Derbyshire has all that...and as you stated  it's tooled.

And what costs the most is not the lathe...but the tooling!

A Schaublin 70 would be wonderfull! as it uses the same collets and spindle thread as the F1.
    Bring your BIG checkbook though....they start in the "they want $3K for that piece of ()@*()!"
And go up from there....you and I have seen what's happened to F1's lately on the bay.... :hellno: :hammerbash: :wallbang:

An old Stark or Ames or Pratt and Whitney....with 3C collets would be wonderful....but it needs to be pristine to be worth it....unless you REALLY REALLY want to share in my ill mental health :hellno:

JMHO.......worth exactly what you paid for it......

Dave




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Damned ijjit!

Offline b.lindsey

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Re: Do I need a new lathe?
« Reply #4 on: January 17, 2013, 04:57:22 PM »
That's closer than most of us can or even need to work to consistently.  Working to tenths would normally require a temp and humidity controlled environment as well. In the wrist pin button case, I am thinking that the wrist pin hole itself will grow with heat as much or more than the teflon but would have to look up the coefficients of expansion. Sorry, not much help there I know. Of those you mentioned I would think the Cowells would be a nice fit but certainly not cheap.

Bill

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Re: Do I need a new lathe?
« Reply #5 on: January 17, 2013, 04:59:58 PM »
The Cowells is very good!   but its about the same capacity as the Derbyshire...and takes the same collets...8mm.    So other than a leadscrew and a saddle.... does it buy you anything?.....

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

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Re: Do I need a new lathe?
« Reply #6 on: January 17, 2013, 05:14:59 PM »
http://www.ebay.com/itm/SCHAUBLIN-SV70-INV-4659-/350586829164?pt=LH_DefaultDomain_0&hash=item51a09a796c

Actually not too bad price wise....based on what I have seen before anyway......and fairly well tooled....

....but not cheap

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Mosey

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Re: Do I need a new lathe?
« Reply #7 on: January 17, 2013, 05:28:15 PM »
Dave,
Showing me Schaublins will probably get you a lawyers letter from my wife, "alienation of affections" I think it's called. But you still have to move the saddle, indicate it  parallel with the spindle, lock it up, indicate again cause it moved, etc. Might as well use the Derbyshire and make the rest of the toys to go with it.
But don't you like to wipe off that shiny Swiss metal and look at the frosting for a couple of hours?
I think there's a Habegger for sale...
Keep the thoughts coming guys.

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Re: Do I need a new lathe?
« Reply #8 on: January 17, 2013, 05:53:10 PM »
OK then

If rational thought is not part of the eqaution....well that opens up all kinds of opportunities! 8)

Hell I could have all kinds of fun being a buyer for you!....Glad to help!

Of course I love touching all things Swiss!....:slap:

If the cross slide is in good shape on the Derbyshire or the Schaublin...you should be able to move it and it will maintian it's sqaureness to the spindle.
You do have the stop on the bottom side of the Derbyshire cross-slide....right?

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline ttrikalin

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Re: Do I need a new lathe?
« Reply #9 on: January 17, 2013, 06:08:18 PM »
Mosey,
I have an informed opinion on Sherlines. I own two lathes and a mill from them. 

Sherlines are cheaper than the nice machines. Depending on the operator, you can do sub-thou work. Trivially so under a microscope. Look at Jerry Kieffer's work.

For example, factory tolerance for spindle runout is 0.00025" - as per instructions, you can tighten the spindle nuts and halve the tolerance (with obvious impact on bearing life). Also, for small stuff, it can spin out to 10000 rpm (with a puley mod).

Accessories are expensive. Some work to make it "sub-thou" accurate may be needed. E.g., tailstock alignment will not be perfect out of the box. An adjustable center, or an adjustable tailstock modification eliminates the problem.

IMHO, turning a wristpin from teflon or steel to tenths accuracy is within the capabilities of the machine, right out of the box, without a microscope. (You may need the compound crossslide [an accessory, alas] to improve resolution by advancing the cutter from a tangent. ) 

What Sherlines *are not*, are sweet machines - compared to the Schaublins of the world, or Dave's Waltham.

tom
« Last Edit: January 17, 2013, 06:12:05 PM by ttrikalin »
take care,

tom in MA

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Re: Do I need a new lathe?
« Reply #10 on: January 17, 2013, 06:23:31 PM »
What Sherlines *are not*, are sweet machines - compared to the Schaublins of the world, or Dave's Waltham.

Wellllll it ain't sweet yet....but its getting there..... 8)

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline mklotz

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Re: Do I need a new lathe?
« Reply #11 on: January 17, 2013, 06:54:21 PM »
Of course I love touching all things Swiss!

That's what James Bond said in Dr. No.

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Regards, Marv


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Online steamer

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Re: Do I need a new lathe?
« Reply #12 on: January 17, 2013, 07:06:46 PM »
Of course I love touching all things Swiss!

That's what James Bond said in Dr. No.


....and he did just fine!
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Online Tennessee Whiskey

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Re: Do I need a new lathe?
« Reply #13 on: January 17, 2013, 07:18:25 PM »
Jo-- animate or inanimate

Mosey, just as so many of the  things us older kids enjoy comes down to is how bad you want it.
If you're striving for the 0.000000001 results it's there but it's gonna cost you. I think we would all agree that outside of something like as Marv said, a 17 cylinder rotary cross compound Corliss thingee that was fired by some kind of plutonium something or other, we could (or y'all could )build a real nice historic runner with any old lathe,hack saw,nice files, and good pillar drill with one of those HF milling tables. Get what you can get half - ss'd serviced and tooling for and enjoy it. On the other hand if the CFO and your accountant agree it's ok; I'll bet there some real nice Swiss CNC assisted stuff we'd all like to see you use.
Eric

Offline Mosey

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Re: Do I need a new lathe?
« Reply #14 on: January 17, 2013, 09:25:48 PM »
Yo Eric,

CNC is "can not cut" for now, or at least until I can make real nice things manually. Although, I admit, I love DRO's, so that is not far from it.
For now it is going to be get the Derbyshire singing and keep an eye open for a sweet Swiss miss.

Mosey :cartwheel: :cartwheel: