Need recommendations for an inexpensive lathe to make metric threaded stuff

Virtually every thread in photographic equipment is metric and while thread diameters range (realistically) up to 88 mm or so, I've seen some as high as
120 mm too). In order to make specialized adapters to mount unusual (and mostly industrial) lenses to "standard" photographic equipment, it's necessary to make hollow cylindrical adapters with different threads at the two ends.
I'm not looking to go into business, I just want to be able to make adapters as the need arises. Assuming that 3" (~77mm) is the largest thread I'd need to cut, what's the least expensive lathe I could purchase?
Norm
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For new machines, I would start by looking at Sherline. That would probably be the cheapest machine with good precision out-of-the-box. The maker can also be counted on to be around for awhile (so you can continue to get parts and accesories).
If you don't mind a project, many have gotten good results with the import 7x10" (often now 7x12") lathes which cost about $400 from places like Harbor Freight and Grizzly, but you will have to spend time tuning up the machine before you can do any work that counts. There are many web sites devoted to improving these machines (Google "mini lathe"), but you may not want a lathe "project". Micro Mark also sells a "tuned up" version of this machine for more money.
My favorite for what you want to do would be to get a used Austrian-made Emco Compact 5 (Note this is Emco and not Enco). The new ones are Chinese made and probably are now not worth the price difference over the Harbor Freight 7x10 machines, but older Austrian ones show on Ebay occasionally (but not frequently) for not crazy money (between $600 and $800). Emco also makes something called a Unimat, but I think a Sherline would be a better choice than that.
Norm Dresner wrote:

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JFTR: EMCO gave up producing for the non-pro market several years ago. IIRC it was in the 90's. They sold that part to B&D. So it is not EMCO making that junk, but B&D.
Nick
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A friend of mine here in Florida has a Shoptask machine about 10 years old. He builds telescopes and cuts all his own threads and also has a special setup to cut and grind the optical glass blanks for the lenses. His work is pretty impressive. You could try the Shoptask users group for some more info.
http://forums.delphiforums.com/n/main.asp?webtag=Shoptask&nav=message

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Norm Dresner wrote:

Probably one of the import 7x lathes with a metric leadscrew and half-nut set would do. I've never seen one retailed that way in the U.S., but www.littlemachineshop.com has all the parts and conversion kits to go either way. Sherlines aren't set up to do threadcutting out of the box, you'd probably spend a lot more than what one of the imports would run you with the conversion kit and have a lot less rigid machine at the end of it. The 7x lathes are regularly sale-priced in the $300-350 level( I lucked out and got mine for $225), you'd have to look up the metric leadscrew kit's current price. You'd probably need a 4 jaw chuck to go with it, maybe a 6 jaw(very handy for thin-walled workpieces), too. There's some support groups for the 7x lathes over on Yahoo, if you'd like to snoop around. Out of the box, they tend to be a work in progress, the new owner usually has to fix up some deficiencies. If you've got Harbor Freight around anywhere close, you can see what one looks like in the store, others retail the same machine with a longer bed for more.
I've done this conversion, it's not difficult. It's not something to stop in the middle of a project to do, not exactly quick-change, but not a long machining project, either. I've bored a 3" hole in a 6" aluminum flange with my 7x and finished the outside of the flange, too, I'd consider that about the outside limit for turning with this machine and motor combination.
Best figure around $400-500 for the budget to get you started with lathe+tooling unless you've got a bunch of stuff squirrelled away.
Stan
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On 28 Dec 2005 08:15:27 -0800, snipped-for-privacy@prolynx.com wrote:

This one has english *and* metric threading. http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumberD859
Rrandy
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Randy Replogle wrote:

That looks like the way to go. Bed looks beefier than the 7X variant.
If you want a slightly better quality, try Lathemasters 8x14. Not sure about metric threads on that one, but if it's a matter of change gears, buy the HF gears.
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On Wed, 28 Dec 2005 17:25:04 GMT, Randy Replogle

Which it does more easily depends on whether it has a metric or inch leadscrew. The differences are that a machine with a metric leadscrew will probably have more and better choices of metric threads, and one need not keep the leadscrew engaged thruout the threading operation -- not that it's a big deal to do so. I usually do anyway. My lathe (8 TPI screw) does both, but it's missing a couple of metric threads and has some wierd ones that aren't in any standard.
I'm going to HF today anyway, will have a look if they have one of these on the floor.
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On Wed, 28 Dec 2005 14:12:34 -0600, Don Foreman

BTW, the reason I'm going to HF today is because they have those Cen-Tech don & line laser levels on sale for $7.99. I don't need another level, but I know that the lasers in those things are pretty good -- better than most inexpensive laser pointers. The dot is visible on a treetrunk 50 feet away in daylight. I intend to pull out the laser and can the rest. I'm thinking about making a mount for it to put on the CO2 pistol my daughter-in-law uses for shooting squirrels that raid her bird feeder. I mentioned the idea a few days ago and her eyes lit right up as she said, "Oooo, COOL!" Maurauding greedy rodent, behold the red dot of your imminent demise ...... phut!
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On Wed, 28 Dec 2005 14:12:34 -0600, Don Foreman

They didn't have the 8" lathe on display. The 9" lathe had a 16 TPI leadscrew. Better check to be sure that a lathe like this has all of the metric threads you'd want. I think most camera stuff is 0.75mm thread, so you may be OK.
Check out Richard Kinch's page on making adapters at http://truetex.com/micad.htm
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wrote:

Well ... It looks perfect for the task I specified, BUT ... It's going to take a lot of fancy footwork to justify $500++ and the space it'll occupy when I'm not using it. Of course, I could also do some interesting work at my secondary hobby -- Model Railroading [with a heavy emphasis on the Modeling] -- but still, it's an awful lot of machinery to sit idle most of the time.
OTOH, I've always wanted a lathe to make some of the more esoteric parts for modeling locomotives from scratch ...
I'll have to think about this. I'm not convinced yet and there's still the Chancellor of the Exchequer (SWMBO) who heads the local finance committee ;-))
Norm
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Norm Dresner wrote:

Norm Not to rehash any of the preceding, but the $300 minilathe will meet your needs. Anything more is.... more :)
Have fun
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FYI. An Emco Compact 5 just popped up on Ebay.      Item number: 7576638331. I don't know anything about the machine or seller, but this would be better for your purpose if not too much more than the Chinese 7x10s.
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    It could work very nicely for his task if this were the CNC version (which I have). That makes threading up to shoulders totally automatic.
    Also -- the nice quick-change toolpost which comes with the Compact-5/CNC would work nicely for the task. What is on this lathe is *not* the quick-change toolpost.
    However, this one would be manual threading, and it is not clear that any change gears come with it other than the ones (nylon) which are already mounted on it. I'm not sure how easy these gears would be to get, since the machine has been totally discontinued by Emco-Maier (the maker).
    Also -- the three-jaw chuck (a rather nice little one) should also have the alternate set of jaws, for gripping the OD of larger items. I don't see any sign that they are present, either.
    The tailstock taper is MT-1, and the spindle taper is MT-2. The chuck is mounted to the spindle with three through bolts (visible in the close-up of the mounted chuck. 4-jaw chucks mount with four bolts instead of three, with one threaded hole in common between the two patterns, adding up to a total of six holes in the combined pattern.
    It is possible to modify a 4-jaw chuck for a Taig lathe. You need to bore and face a 40.00mm hole in the back to accept the spindle nose, and then drill the four holes in the proper places between the jaws. I did this for my Compact-5/CNC prior to my acquiring a genuine Emco-Maier one from a later eBay sale.
    The carriage has gibs made of filled nylon (I think) on the bottom of the bed. These flex enough so they need frequent adjustment for very little wear. I have made aluminum backing plates to go behind these, and they make a *major* difference in the life between adjustments.
    Enjoy,         DoN.
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wrote:

I wouldn't go smaller than a 6" lathe. Before you make the threads you have to make the tube. Turning 75mm to 100 mm dia tubing takes more rigidity to avoid chatter than turning watch parts.
Any lathe will cut metric threads if it has the right change gears installed --127:100 tooth for lathes with inch leadscrews. A lathe with a metric leadscrew might be more convenient, but for fine threads you're better off never disengaging the leadscrew anyway -- and fine threads only take a very few passes.
I'd worry about the Chinese imports here because you're probably expecting smooth-running threads that fit. A little bit of taper (headstock misalignment) can screw that up.
You probably know that you will have to anodize your parts, , not just for appearance but so they work. Un-anodized aluminum threads gall very easily. Anodizing is easy. Getting a good black is not quite as easy but quite feasible with the right dye.
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wrote:

===============Lots of good suggestions offered.
One that you may want to consider is one of the 7 X 10 [or 12] lathes with a metric conversion kit [leadscrew and halfnut]
see http://littlemachineshop.com/products/product_focus.php?Focus=Conversion%20Kits
Uncle George
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