I have been messing with camera lenses and was talking about getting a
lathe to make some adapters and maybe learn something and have fun.
(If I just wanted adapters it would be far less expensive to just pay
someone to make them.)
My wife pre-empted my dithering about the "best" choice and got me a
Proxxon 230 as a birthday present. So now I get to dither about
So, my first question is hopefully simple; should I get the Proxxon
splash shield / chip catcher tray gadget? It looks like a sensible way
to reduce mess, but I have no lathe experience.
What is its native threading system? For most lens adaptors,
you will want metric threading capability.
O.K. According to this:
it is metric.
You'll want the boring tool set -- since you need to bore the
center out of your adaptors.
No need for the die holder -- you'll be cutting non-standard
threads for which you could not afford a tap or die. :-)
The quick-change toolpost will be a big hell as you switch
between turning and threading tools (internal and external). Get extra
holders. I see four total to be a good choice for what you want to do.
Both the 3-jaw chuck and the 4-jaw chuck will be good to have.
But the lathe comes with the 3-jaw, so you don't need another until you
start milling with a rotary table. And I don't see that as needed for
what you are doing.
Hmm ... if you are going to make bayonet mounts (which many
cameras use for their lenses), you will want the milling capability, and
the rotary table down from the milling section. I don't see a rotary
table listed, so you would have to get one from the Sherline folks to
have one of reasonable size.
No need for the collet set for what you have specified you want
to do --but as you get to doing other things, it will me nice to have.
The fixed steady is probably not big enough for most adaptors or
The three piece thread cutting set for sure. (And learn to
grind your own tools from HSS lathe blanks.
Where are you going to be setting up? I don't see you needing
to use flood coolant, so the splash part you don't need. If you're
going to be doing this in the dining room or other living part of
the house, the assembly could help control where the chips go, so you
can clean them up more easily.
I see you likely to be using aluminum and brass, neither of
which really need flood coolant, and the aluminum can benefit from a bit
of WD-40 spritzed on as coolant, while the brass cuts dry very nicely.
Brass makes nicer and smoother threads, but it costs more and weighs
If you don't already have one, get a shop vac to clean up the
And in addition to the listed things on that site, you will also
0) *Absolutely* -- safety glasses for yourself, and for whoever
comes to look over your shoulder. Spares for when the original
ones get too dirty to see through.
1) Micrometers in mm (since the lathe is calibrated in mm). At
the least 0-25 mm and 25-50 mm. The maximum capacity of the
lathe barely goes over 50 mm, so probably not the 50-75 mm one.
2) Thread pitch gauges for metric threads.
3) Digital caliper will be convenient for quick measurements
and for converting between inch and metric dimensions. Typical
inexpensive ones go from 0-150 mm (0-6"). They will eat up
batteries quickly, so plan to use SR357 or SR44 in place of the
original LR357 or LR44 cells. They will last longer, at least.
Beware that the "off" button does not really turn it all off,
just the LCD display. It still keeps running internally to keep
track of when it is moved, so it has the right reading when you
turn it back "on".
You can't trust it to provide as much accuracy as the
micrometers, but it is quick to use and read.
4) A scissors style knurling tool to allow knurling parts for grip.
A "bump" style knurling tool needs a much heavier and more rigid
lathe to drive it.
5) A bench grinder for making your own threading tools and other
turning tools -- and for re-sharpening what you buy.
Probably lots of other things, but these are what I can think of
at the moment.
Certainly others will think of other things. FWIW, I have made
lens adaptors in the past, and expect to make more. I've even made some
with a much less capable lathe.
Thank you for the very comprehensive suggestions!
Comments interspersed below:
On 4 Mar 2012 06:24:57 GMT, DoN. Nichols wrote:
I would probably take bayonet mounts from junk lenses and bodies. But
I can see that milling and a rotary table might come in handy for many
things. My father donated an old Unimat II (not threading, but it will
convert to a mill), and amazingly I have a very small rotary table
from a yard sale!
Yes, I only have an inch micrometer so far...
The 52mm specification is European style, giving the radius not the
diameter of the swing over bed.
Great! I've never had my hands on a Unimat II, but the even
older Unimat SL-1000 and DB-200 have problems with rigidity, since the
bed is only steel rods supported only at the ends. If the Unimat II has
a cast bed, then it should be significantly more rigid, like my
Emco-Maier Compact-5/CNC. (Still not up to my 12x24" Clausing, of
[ ... ]
[ ... ]
That makes the range of sizes you can handle better. I was
thinking that it might be a bit tight for some sizes of camera, even if
you stick to 35mm ones. I'm used to "Centre height" being used for the
European style, and "swing" for the US style of dimensioning of a lathe.
Interstingly enough, the Compact-5/CNC is specified in Inches of
swing over the bead (diameter) even though it came from Austria.
Make that a four-micrometer set. :-) There are pretty good ones
(except perhaps for long term wear and retaining the accuracy) made by
the Chinese and sold at various places. The ones which I have seen
(four mic sets and 6 mic sets) have been inch mode ones, but presumably
they also make and import metric ones.
For one micrometer, a digital is nice for the ability to switch
back and forth between inch and metric. (But somewhat expensive.) I've
got two 0-1" ones, and one 1-2" one (each of the 1" micrometers is kept
near a different lathe, the 1-2" one near the Clausing. (The
Compact-5/CNC is a 5" swing (diameter, not center height). For beyond
that, I have a 0-6" set of Brown & Sharpe mics to cover to the max size
of the old Atlas/Craftsman 6" lathe I started with, and a collection of
Starrett ones of various sizes to fill things up to the 12" size.
(Though to be honest, *most* of the time, the 0-12" digital caliper
(Mitutoyo) is accurate enough. But if I did not have those micrometers,
then is when a job would come up where the extra accuracy would be
[ ... ]
I got my first one to use with the Compact-5/CNC -- way too
small for bump knurling -- and I really don't like it on any system. I
found a really nice one by Aloris to fit my BXA sized quick-change
toolpost . It has the two knurls on two arms which move in a vertical
dovetailed slide, each moving in the opposite direction with a leadscrew
with left-hand threads on one end and right-hand ones on the other.
Once it is set to the proper center height, I can just drop it on to
knurl any size within its range without having to re-adjust the height.
The Unimat II is from the 60's and has rods supported at the ends, so
it will never be a great mill, but it may be good enough for some
Yes, I suspect that for most lens threads and such I could survive
with even 0.1mm accuracy, which should be easy even with a calipers.
For many other things "make it fit" is probably the order of the day,
and absolute measurements are not relevant. But I suppose that it is
inevitable that something will come along requiring a real number...
I did a little casual looking on the web and it looks like casual
looking is not going to do it.
There are many tools that will do up to about one inch, which is fine
for knobs but not so good for an 82mm filter ring.
Tools with large capacity probably don't fit on the small lathe.
Maybe a hand knurling tool is what I need.
However, it may be that no knurling tool is going to work well as the
last step on a filter ring because the ring is thin and will bend
under the load. Maybe I need to knurl first and then bore out the
It is an excellent little machine. Like all well-designed and
well-made lathes, it has a lot of capability within its designed
Bob Hatschek, a former Senior Editor of American Machinist and a
world-class model glider builder (who has flown all over the world in
competition), for decades made a little device known as the "Hatschek
Hook," a tow-release hook for competition gliders, on his Unimat II of
'60s vintage, sold them through the model magazines, and made plenty
of hobby bux with it. He used it for making all kinds of model parts.
So don't diminish its value and capability. It was a clever machine,
well-made, and it has a lot of capability.
If you're into this as a hobby, my suggestion is to focus on what you
*can* do with the machine(s) you have, rather than always pining for
another machine. You can get a lot of pleasure out of learning to get
the most out of basic machines. I decided years ago that I would
define my hobby interest in terms of learning old methods and doing
what I could with them. CNC was my business. It was not my hobby.
I can have a lot of fun with my 1945 South Bend 10L, with rocker
toolpost and all. I could have a lot of fun with a Unimat 2.
BTW, Hatschek uses music wire for a lot of his tools, including the
"production" tools used to make the Hatschek Hook from aluminum and
If you can index and lock the spindle you could manually shave
gripping grooves in the OD of a ring with an appropriately ground
lathe bit in the tool holder. Don't expect to take more than a few
thousandths off per pass.
The carriages on lathes I've tried it on had to be held down against
the ways with one hand while I cranked them toward the headstock to
shave off the chips.
On Mon, 5 Mar 2012 20:00:49 -0500, Jim Wilkins wrote:
I suppose that another way to get grooves would be to take the part
off the lathe, mount it on some expendable wooden rotating and sliding
fixture, and make grooves with a Dremel grinder.
Or if I can get the Unimat II going as a mill I could cut grooves as
though it was a gear-cutting exercise; that would probably be a lot
neater than trying to control a Dremel...
A triangular file would be neater and easier to control than a Dremel
if your hands are steady enough. Wrap a strip of paper around the ring
and mark where the end overlaps. Lay out lines evenly along it and
transfer them to the ring with a prick punch.
To lay out the strip marks you could place it on gridded graph paper
at an angle that gives a spacing you like, with the ends aligned on
O.K. My Unimat SL-1000 is from the mid to late 1960s as well.
Perhaps the same machine? Something like about a 3" diameter 3-jaw
chuck as part of it (the lathe part, that is), and a spindle nose which
is a M12x1 thread.
[ ... micrometers ... ]
In particular, if you need to make a part to fit something which
someone else has at a distance.
First off -- you need the right bore diameter for an internal
thread, or the crests of the threads are likely to bind on the roots of
the matching thread, and by the time that starts shrinking, you have way
too small a thread pitch diameter for a good fit.
The advice someone else gave for fitting a crank to the spindle
(with the lathe unplugged) for making threads which end at a shoulder is
very good -- and applies to many threads made for mounting lenses.
Also -- for measuring outside threads, the best way (if they are
at least three threads long) is thread measuring wires. You put two
wires of the right diameter into adjacent threads on one side, and one
wire of the same diameter into the thread groove on the opposite side
between the first two, and measure over the top of the wires with a
micrometer. There will be a chart, or a formula, with the set of thread
measuring wires to tell you how much to add to the pitch diameter to get
what the micrometer should read. (There are thread pitch micrometers,
but these get expensive, especially with the sets of anvils for
different thread pitches, when you need to get two or three of the same
brand of different sizes so you can share the anvils between them.
Check out eBay auction # 160636274261 for a 0-1" micrometer with
some of the anvils you would need. (Maybe all.) But, you would need
other micrometers of the same brand to use those anvils on the other
Beware that some thread pitch micrometers do not have
interchangeable anvils, but rather are made for a narrow range of thread
pitches, such as: eBay auction # 310383570733 -- which is for 8-13 TPI,
a bit coarse for most lens threads.
This one is 1-2" (25-50mm) and has both inch and metric anvils:
eBay # 330518405934 -- brand/seller is "Shars".
This one is all three sizes in one set: eBay # 150765779502, and
you could use the inch anvils for metric threads, but it would be more
convenient to have metric micrometers for the purpose.
This is one of the ones which I have, but still not metric:
eBay # 260971726026. Note that the ones marked B&S and the ones marked
TESA are made by the same people.
I also have the 0-1" and the 1-2" ones of the same brand. And I
*still* have the thread pitch wires.
Here is an example of thread pitch wires: eBay # 380408293791.
(Hmm ... chart not included. Buy new then. Or pick up a copy of
_Machinery's Handbook_ which will have the formulas for calculating the
measurement over the wires -- and many other things which you will need.
BTW Did I earlier mention a metric thread pitch gauge? You should have
that for sure.
Go to MSC and look there. The trick is to know how big your
tool shank slot is in the quick-change toolpost. The one I got (by
Eagle Rock) fits into a 1/2" slot, which works for the Compact-5/CNC.
This one on eBay will handle up to 2" diameter:
eBay # 300394065202
Here is the AXA version of the knurling tool which I use on my
Clausing in BXA size: eBay # 120748127351 -- also good up to 2"
You can find articles for making your own scissors style
knurling tools, and if you make the pivot point a greater distance from
the knurls themselves, you can make them handle a larger diameter
Note that I've skipped over a lot of bump style knurling tools,
as well as various ones designed for use on turret lathes which would be
awkward on your lathe (but *very* quick for production of many parts if
you *do* have a bed turret attachment.)
Not unless you make an arbor to support the ID of the ring.
But yes, knurling as the first step, then turning the OD to
produce flat areas which end at the knurls is a better way to go.
The best for working on thin material is the cut style knurling
tools -- which are amazingly expensive, so forget it unless you luck
onto one for perhaps $200.00 or so. :-)
It is almost certainly the same machine. I actually has Unimat-SL on
the motor box.
I actually have more than one of them at this point. Last year I got a
box of Unimat spare parts flying in formation at a yard sale. It was
stored in a basement, so there is a certain amount of rust. The base
casting, ways, and lead screw on the base machine are badly corroded.
However, there were spare way rods and lead screw included that are
not bad. I would need to make a base. The pile also had a spare slide,
the milling table, a circular saw and jig saw, and a few other
Yes, getting thread wires and/or a thread micrometer would be good.
Very few of the threads will be as small as 50mm though. It sounds
like the thing to do would be to get a metric micrometer set going up
to at least 100mm, plus some wires.
I guess that there is a good reason why almost none of the step
adapter rings sold these days have knurled edges, despite the
potential convenience advantages. I guess that I will emulate the
professionals and not knurl thin rings, at least until I get some
experience and a few projects done.
Thank you again
I hadn't noticed that you've got more potential machining capabilities than
just your new Proxxon.
Congrats.. the small machines offer a multitude of possibilities, as Ed
As far as needing a lot od specialized measurement tools goes.. well maybe.
Of course it's good to know how to measure parts and dimensions accurately,
a lot can be accomplished with a couple of calipers.
Also, understanding basic principles of how to attain accurate readings are
of significant importance.. it will undoubtedly be very helpful for various
other measuring purposes.
As long as one's not required to make parts to aerospace specs, there will
always be certain limitations of measuring tools and machines.
A caliper isn't the ultimate measuring tool for measuring the minor diameter
between threads, which is easily seen when using one on coarse threads, the
caliper is no longer reading in a straight line due to the thread pitch.
The percentage of error is quite small when measuring the minor diameter of
fine pitched threads on a part with a caliper.. if the user has an existing
example of the threaded part they want to duplicate, then measuring becomes
a matter of comparison of measurements, not to an exact size specification.
I realize that some folks know trig formulas better than I know my own phone
number some days, so math calculations often cloud the issue of making a
measurement, for me. For certain type of measurements, I know I'll need to
do the math, chart comparisons etc.
Otherwise, wires are wires, and if one would care to do the comparisons and
choose wire the same size for a particular thread size, a common micrometer
or caliper can yield the same results.
The benefit of a common micrometer in this instance is that the anvil faces
are wide enough to span several threads.. although a claiper will yield the
same measurement if the jaw faces are placed squarely across, or diagonally
across the wires.
On short threaded sections such as 4 turns of a fine thread on an optical
filter ring, there won't be much room for the measurement tool to make a
Threading charts show how far the cutting tool is advanced into the properly
sized workpiece, to achieve the proper cutting depth for the minor diameter.
These standard recommended cutting depths for a number of popular threads
are etched/engraved into the back side of a "fishtail" thread gage (~$10),
which is a very inexpensive tool for setting up thread cutting tools.
In case it hasn't already been mentioned, Machinery's Handbook contains more
information on metalworking standards and details, than most people are
capable of learning.
There are abbreviated (and not so overwhelming) versions and similar
spin-off books such as the Shop Reference For Students And Apprentices.
So, if one has an example of a known good threaded part, then measurements
can be considered as a comparative process.
Eventually most HSMs encounter threads which are unfamiliar to them, and may
not appear to match any commonly available published standards.
Microphone stand connectors, optics, military/aircraft hardware standards
may all have minor differences for no apparent reasons.
As long as the machine user has an existing part (not just low tolerance
specs listed on a page), almost any matching part can be made depending of
course, upon experience and the required number of tricks up one's sleeve.
I'll not likely ever be an expert at cutting threads, so I usually always
have a "known good" mating part sitting within reach when I'm threading on a
lathe.. and carefully sneaking up on the final cuts works very well for me.
Chucking and threading thin hollow parts can require some additional methods
that don't usually apply to solid stock workpieces.. but there are plenty of
methods to minimalize problems.
Lastly.. threading dies may seem like a logical shortcut/substitute for the
learning process of cutting threads on a lathe, but in general, they aren't.
And then there's that gratification thing, again.
"Bob S" < firstname.lastname@example.org> wrote in message
Except that you usually don't want the minor diameter, but
rather the pitch diameter which is about half-way down the thread
(depending on the shape of the root of the thread).
[ ... ]
Yes -- here is probably the place where thread wires of an
appropriate size and a micrometer is the best bet -- unless you have a
standard to test it in.
[ ... ]
FWIW -- the standard US microphone stand connector is 5/8-27,
which is a problem for many because only some lathes with a quick-change
gearbox include that pitch. My 12x24" Clausing does. I think that the
typical South Bend does not.
Weird threads for military connectors are usually because a
finer thread does not cut as deeply into the wall of the connector
shell. If you were to use a standard thread for say a 2" diameter, it
would be *way* too deep in a connector shell, cutting deeply into the
area where the pins are located. :-)
Yes -- as long as you do have something to test it against.
However, if you are making something to thread into another part which
is across the continent from you -- there is where the ability to use
the measuring tools wins.
One thing which helps significantly with thin-walled parts is a
6-jaw chuck. Even better is one with two-piece jaws, for which you can
make some pie-wedge soft jaws.
They just lead to the "I can't do this because I don't have the
right tap or die." excuse. Far better to be able to define your own
thread at need.
There is essentially no value of knowing a precise measurement of thread
pitch to duplicate or match a threaded piece directly in front of me.
Pitch diameter may be an important spec for hardware design engineering, or
QC quality control compliance, but not really necessary for duplicating or
matching a thread, IMO.
I Will xxxcan only state that I will neither confirm nor deny that I'm
involved in sceret project contracting utilizing my Chinese home shop
My machine dials don't indicate pitch diameter.. they indicate DOC depth of
A 6-jaw chuck would be a great accessory for a variety of reasons, but
pricing a small Bison or other precision brand will cause many/most HSMs to
When the company or university is paying for accessories and tooling, it's a
great idea.. otherwise a chunk of hardwood may produce very good results.
I managed to set up my 1220XL Smithy (no QC gear box) for microphone 5/8-27
thread cutting, by receiving the generous help from a earlier RCM
participant Ted Edwards.
I was glad that there are sharp people who fully understand these things, so
now I have maximum threading capabilities for both the 1220XL and the 9x20
"DoN. Nichols" < email@example.com> wrote in message
I *did* mention that it was important when making a thread to
match another part well out of reach -- say across the continent from
you, or perhaps embedded in a machine which *has* to be kept running.
Yes, making to fit works well as long as you have that other part for
Of course -- but you can use them (and a known starting point
such as zeroing when just barely touching the OD after turning it to the
And -- with a compound set to the proper angle, you can zero
both, use the cross-feed to back away prior to winding back to the
starting end, return to zero, and set in the proper additional DOC
using the compound (compensated for the angle of the compound). I
typically have the compound set to 29.5 degrees as close as I can read
the scale, and compute total needed infeed based on that using the trig
functions in a calculator.
But DOC set does not always translate to actual DOC produced.
Backlash, rake, and give in the compound and cross-slide ways can affect
FWIW I was at a combination tool auction and flea market earlier
today, and one of the things which I saw, was tempted by, but
resisted, was a Buck 6-jaw, with both the inside and the outside
jaws, new condition, with adjust-tru mounting. It was about 4"
diameter. If I were still using my old Atlas/Craftsman I would
have gladly paid the asked $250.00. But it is just too small
for my 12x24" Clausing, and I already have a 6-jaw Burnard
Pratt, though without the outside jaws.
So -- not dirt cheap, but if you can use it, difficult to
Yes. Especially in combination with the 4-jaw chuck.
Yes -- any basket-of-gears threading setup can be set for almost
any thread in the same system -- and with a pair of 127/100
tooth gears, even for Metric if made for inch or vise versa.
But it does take some computation.
But the real benefit, IMHO, to a quick-change gearbox is that
you are not tempted to leave the feed in an inappropriate range when you
are switching between turning and threading -- you tend to leave the
gears set up for threading -- and on into the next project until you
have to set up for a different thread. Been there with the little 6x18
Atlas/Craftsman. And with proper lube on the pot-metal gears, you hands
take a *lot* of washing just to get to gray from black after working
with those gears. :-)
Yep, I definitely recommend an indoctrination period of becoming familiar
with the differences in actual results compared to expected results such as
DOC depth of cut relating to feed dial scale markings.
I've gotten used to making notes and reference examples and hanging them in
plain view of the machine controls, as a deterrent to ohshit! moments.
Especially in the huge numbers of imported models which are marketed to
potential owners who may be interested in either metric or inch based
features, whereas we're aware that one size does not fit all.
When trying to remove metal in thousandths results in accumulative errors by
counting metric dial ticks, it can fairly easily lead to confusion (for me,
doesn't take much to do that these days).
Wow, $250 for a quality 4" 6-jaw.. and that's still considerably less than
some new quality brand 3-jaw models that size.
I just picked up a used 4" Dunlap 4-jaw for the 7x mini lathe, since the
only spindle accessory included with this new machine was a 3" 3-jaw.
The Dunlap backplate is made to fit a 3/4" thread, so I'll be making an
aluminum backplate to replace it which will match the spindle flange of the
It would be easy enough to just cut the existing backplate to match, but
there may be a future use for the original threaded version, so I'll
I wouldn't feel that a 7x mini from China is deserving of a good 6-jaw a far
as a cost effective upgrade.. especially at new prices.
I would've then felt compelled to find a lathe of equal quality to match the
chuck, but that's just me.
"DoN. Nichols" < firstname.lastname@example.org> wrote in message
And -- to add to the problems, I've seen machines with dials
marked 0-0.125" -- but there was a slight gap between the 0" and the
0.125" points. Turns out to be something like 0.128" per turn
(3.25mm/turn) so they could use the same leadscrew and nut on both Inch
and Metric machines. Never mind what happens when someone is mentally
counting the turns adding 0.125" per turn. :-)
Indeed. I'm still sort of sorry that I skipped it. But it was
a threaded backplate, so I would have had to make another backplate for
the Compact-5/CNC (the most appropriate size lathe I have for it which
is good enough to be worth it). And the Compact-5 needs access from the
tailstock end of the spindle to access the three (or four for a 4-jaw
chuck) screws which pass through the chuck body to mount it. Kind of
awkward, in that I would have to dismantle the adjust-tru assembly to
access the mounting screws. They go directly into the flat end of the
spindle nose. (A total of six threaded holes, with one of them acting
as a corner of both a triangular pattern and a square one.) The OD of
the spindle nose is a precise 40mm, and the back of the chuck is turned
with a matching recess for centering.
This may have been a 3/4" (or perhaps a 1") thread. But since
it is an adjust-tru, it is easy enough to make an alternative backing
plate to fit to something else.
Same with the beat up old Atlas/Craftsman 6x18 lathe -- one
prior to the Timken roller bearing spindles.
I understand it totally. That is why I don't have that chuck
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