In article , DoN. Nichols wrote:
In article KfjEb.422665$ao4.1358065@attbi_s51,
Loren Coe wrote:
In article , DoN. Nichols wrote:
In article uG3Eb.72868$8y1.273479@attbi_s52,
Loren Coe wrote:
[ ... ]
this is a basic design feature that marks
the very low end machine, the lack of, i mean. my manual feed requires
turning a handwheel on the end of the lead screw. not very handy.

That also suggests that you don't have half-nuts -- to decouple
the carriage from the leadscrew.

there are half nuts, no thread dial.

If you have half-nuts (in the apron), you really need a
threading dial. And it is possible to *make* one for the lathe. One
quick-and-dirty way is by finding a gear with a tooth pitch which
matches the thread pitch of the leadscrew. You'll have to mount it on a

afaik, the screw is 8 tpi, most of these smaller imports seem to be.

shaft at a bit of an angle, to make up for the lead of the screw.
Better is to make one which is pseudo-hobbed by a tap which matches the
leadscrew, so you have a better match, and so the teeth are angled
properly to engage the threads on the leadscrew. The number of teeth
on the gear are critical -- and I would have to go to _Machinery's

this sounds like a decent project, i need to start doing some more
research. i never thought i would need much threading and that has
been true, but it still would be fun to accomplish.

.... the lead screw is the y-axis feed
whether power or manual. if you disengage them, you can move the carridge
by hand (literally).

You mean push it along -- no handwheel to move it?

yes, push it, but the handwheel is on the tail end of the screw.
you disengage the clutch, then turn the handwheel (half-nuts still
on). of course this means the handwheel also turns under power feed.
not really too neat.

[ ... ]
i have come to understand that what i have is pretty much a
kludge. the rack gear would be a real bonus (on low-end machines).

Interestingly enough -- the Taig (Peatol in the UK) has a rack
gear and handwheel -- but *not* a leadscrew. You are expected to do
your threading with dies on that machine.

it may not sound like i am happy with this 3n1, but i am, for the
amount of use it gets and my needs. still, it is fun to think about
the better machines and their features.

I understand. I started with a Unimat SL-1000 (the leadscrew
was the *only* way to move the carriage.) I then got an old
Atlas/Craftsman 6x18", which had the rack -- with the handwheel purely
manual -- and all power feed was via the leadscrew -- with a
basket-of-gears threading setup, and a chart on the inside of the gear
cover.

that is basically the 4015 lathe section, sans the rack gear. they
give you a 127/13x(?) duplex gear so you can cut metric threads, too.

On some systems, the coupling to the power feeds is via a
clutch. On mine, it is a set of gears that engage or disengage with a
lever, which means that you sometimes have to wait for teeth to align
before you can complete the lever motion. The lever rotates a short

i have not tried to use the lead screw clutch when the motor is on,
never had the nerve. if that is okay to do, it might make some things
easier.

Where is this clutch? The ones which I was talking about are in
the apron, used to connect the power derived from the drive screw
rotation to either the cross-feed, or the longitudinal feed handles.
These engage smoothly, and can be set to slip before you are in danger
of damaging your machine.

The ShopTask, however, has a dog clutch (which enages only at
one point in the rotation), to couple the spindle's rotation to the
leadscrew. (It also achieves reverse, by connecting to a
counter-rotating gear with a second dog clutch enaged by the same
lever.)

yes, that is what i _thought_ i had. this clutch is located in the base
of the pedestal and from the drawing, it looks like two "spiders" with
four legs. maybe that is a "dog clutch"? but just the one clutch.

another poster suggested it s/b okay to use w/power on. will pull
that cover plate and then maybe give it a try. Thanks, --Loren