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
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?
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:
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
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.
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.
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.
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
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
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
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
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
It could work very nicely for his task if this were the CNC
version (which I have). That makes threading up to shoulders totally
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
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
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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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