In article ,
Doug Goncz wrote:
From: (DoN. Nichols)
d) Certain other parts of the machine look suspect. As an example,
[ ... ]
the compound set at an angle for whatever purpose. Where I see
this to be a real pin would be in threading, where it is
traditional to have the compound set at 29-1/2 degrees to feed
in almost along one flank of the thread you are cutting.
I took a closer look at page 28. The tool holder does hold a tool across or in
line with the feed. But no, you can't set the tool square to the work using a
traditional symmetric threading tool, and feed along a flank. I'm thinking of
using a T6 Diamond Toolholder.
Hmm ... I don't have one of those. Does it happen to be at just
the right angle to make a 60 degree included angle on the tool bit? (I
saw where you negated this idea afterwards -- because it is too big for
the toolpost's slot.
What I would suggest here is to make a new sliding block for the
compound upper dovetail, and thread it to accept one of the various
recent small quick-change toolposts. This would allow you to set the
angle of the tool independent of the compound angle.
In an email to Don, I mentioned that with a lower speed limit of 500 rpm, the
biggest piece of steel you can cut on this lathe is less than an inch.
First off -- the 500 RPM figure is the minimum speed for the
milling spindle -- not the lathe spindle. According to the manual, it
is 560 RPM for the lathe spindle. And that 500 RPM for the milling
spindle has an unresolved footnote, which I suspect means that speed is
with a 50 Hz power line (UK power, not US), and 560 RPM for the
alternate (US) power.
Hmm ... I calculate 261 SFM for 2" diameter-- which should be
within reason for carbide inserts, at least. :-)
For a full 5" diameter, that works out to 654 SFM. But remember
that you can't turn a 5" diameter workpiece any longer than the maximum
overhang of the toolbit. The maximum you can swing over the carriage
and cross-slide is: 2.36 inches (roughly 60 mm).
So -- with the maximum diameter over the cross-slide, I get 308
SFM -- still within reason for carbide and mild steel. I sometimes run
850 RPM with 2" diameter mild steel and carbide on the Clausing (445
SFM).
e) Even the headstock spindle only has a MT-1 taper, same as
the mill spindle and the tailstock. Normally, the headstock
spindle is at least one Morse Taper size larger than the
tailstock.
Modularity? Two dead centers are supplied. And no dog or drive plate.
More likely an indication of a wimpy spindle -- with a serious
limitation on the maximum size of stock which can be fed through the
spindle. Looking into the specs, I see a maximum stock through the
spindle of 0.35" (9 mm). Depending on what you want to do, that also
could be very limiting.
And -- the smaller the bore, the less diameter in the spindle,
which increases the chance of bending it with an optimistic cut, as
frequently happens with the AA series lathes (sold as the Craftsman 109
series).
a) Threading will be a real pain, as this machine does not have
half-nuts and a threading dial to allow you to disengage the
leadscrew, return the carriage, and re-start another pass on the
threading. Instead, you have to stop the spindle, crank the
tool out of engagement with the workpiece, reverse the spindle
to get back to the starting place, stop the spindle, crank the
tool back in enough to make the next (deeper) pass), and
re-start the spindle in forward.
This doesn't sound like a problem. I'm very patient. But 500 rpm threading?
Might as well put a crank handle in the mill spindle and turn it by hand.
Agreed. The crank is the only way to go for threading to a
shoulder. (I would suggest that you be careful to make the crank well
balanced, just in case you accidentally hit the power switch while it is
installed. :-)
I will ask HF by email if they know what the leadscrew pitch is.
That limit of less than 3/4" stroke for the tailstock ram means
a lot of re-settings of the tailstock to drill a center hole through the
workpiece in preparation for internal thread or boring.
It's only 35 pounds. My dream is the red lathe that cuts metric and inch, and
takes the same steady and follow rest at the famous 7x10. 235 pounds. Not ready
for a permanent install in our 9x10 foot craft room.
Can I use combinatorics to output all possible pitches or will that output some
banjo-impossible combinations?
The banjo appears to be part 19 on page 26 (they call it "Change
Gear Frame". And looking more closely at it, it has only one slot for
the gears to mount in. The other (curved) one is for adjusting the
gears into mesh with the spindle gear. This will *seriously* limit your
choices of threading gears. (I'm not a all sure that there is room for
a more elaborate banjo for more complex threading setups, even if you
made one from scratch.
Looking at the drawing on page 8, there appears to be
insufficient room for extending the banjo with a second straight line
for extra gears, in part because the motor and belts occupy the space
which would otherwise be used for that function.
Another thing which appears to be missing is a tumbler gear
assembly to allow reversing the threading feeds, for cutting left-hand
threads. (The reverse *switch*, of course, reverses everything at once,
which is no help there.
Frankly, I would suggest that you would be better off with an
old Atlas or Atlas/Craftsman 6" lathe in good condition, which comes
with tumbler reverse, and a full set of gears with a proper banjo so it
can cut *many* threads, even the ones like 27 TPI which are often left
off of quick-change gearboxes.
And -- it has proper back gears, so the three belt steps in the
spindle pulley can give you six spindle speeds, including some
reasonably slow ones.
It is a bit bigger than this, because of having a full 18"
between centers, but should not be that much heavier. (The motor would
be carried and installed separately, of course.)
Look for one of the later ones, with the roller bearing spindle,
not the older one with sleeve bearings, such as my first machine.
And also -- remember to avoid the 109 series Craftsman lathes,
which at first glance seem similar, but are quite wimpy. They were made
by a different company, and are quite marginal in several way.
It is too late for the Patina auction and flea market, which
sometimes has such machines. And for the steam show at Berryville Va,
which also does.
Have you gone to the Cabin Fever and Iron Fever shows up in
Pennsylvania? There are lots of old machines for sale there, both
auctions and consignment sales. I've picked up machines there -- though
not lathes, as I already had the nice Clausing 12x24" and several
smaller ones.
Good Luck,
DoN.
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