The magnetic sign stock is more user friendly than you might
think - most of it is directionally magnetized. The back side is
strongly magnetic; the face is almost non-magnetized.
Roy
--- In 7x12minilathe@..., "John" <moran03@e...> wrote:
The cross slide lead screw is exposed when the compound is removed
while using the ball fixture so your idea of using a magnetic card
seems like a good one, especially since I often use the ball
fixture
on aluminum.
And, you've convinced me to use a clamp scheme instead of a set
screw
to retain the bearing. I think I can slit the bottom of the
bearing
holder and add a cinch screw to accomplish this. It may look a bit
strange for a while until I come up with a scheme to mill the outer
part of the holder to match the diameter of the dial --
unfortunately, I can't turn it to size and leave a place for the
cinch screw and I don't own a mill so I guess it will take some
extra
ingenuity. Or a visit to a friend with a mill...
Thanks for the advice.
John
--- In 7x12minilathe@..., "roylowenthal"
<roylowenthal@y...> wrote:
There's a compound pivot mod that moves the compound's pivot
point
close to an inch towards the centerline of the lathe - should
reduce
the number of times the feedscrew is exposed. Flexible magnetic
sign
material holds onto oily metal better than duct tape & comes free
in
the mail from realtors, long-distance providers, pizza places,
etc.
Using a setscrew on the outer race of a ball bearing is not a
good
plan; the outer race will distort enough to give the bearing
a "notchy" feel if the screw is tight enough to actually hold
anything. Any retention method should distribute the force over
as
much of the bearing as possible.
Roy
--- In 7x12minilathe@..., "John" <moran03@e...> wrote:
Hi Bob,
Thanks for the info on your mod as well as the link to the
cross
slide mod pictures. I particularly like the way you clamped
the
inner race; if my wild scheme doesn't work out I'll copy yours.
I tend to be a "successive approximation" worker, that is when
possible I try to make things in such a way that the parts can
be
tried prior to completion. The cross slide mod I'm attempting
is
a
good example in that the change to the carriage is now done
plus
I've
completed the lead screw extension and have it in place (but
the
dial
is still where it used to be because I don't have the bearing
yet),
held with a longer bolt. This extension has the groove for the
dial's friction spring as well as the land for the inner
bearing
race
to butt against. All I need now is the bearing and spacer.
The
extension is easily removed so I can revert to the original
setup
quickly, except I can't put the material back into the
carriage :-
)
Pictures of the present state are near the end of the page on
my
lathe site:
There is 5/8" additional thread exposed on the leadscrew so it
will
be quite a bit better than the present setup; I can make the
next
approximation - a new leadscrew - later if necessary.
My scheme for inner race retention is not as positive as yours.
I'm
trying to copy the method used on the minilathe's compound
slide
except that a ball bearing will be included. That is, the
handle
will take the bearing's thrust via the dial. Very few parts
needed
but hard to say if it will have excessive slop - my compound
has
about 3 mils.
I'm still agonizing over a simple way to retain the bearing's
outer
race which would also allow easy disassembly so I can revert to
the
original setup if it doesn't work as I hope. Loctite or a press
fit
would make the bearing more difficult to extract so I'm leaning
toward a set screw.
With the material removed from the carriage I find that the
cross
slide lead screw is exposed when the toolpost is centered as it
is
when using the ball fixture. It's unclear how to protect this
in
a
way which won't interfere with the spacer - another use for
duct
tape, maybe ;-)
John
--- In 7x12minilathe@..., "v45bob" <rosunley@s...>
wrote:
I made a new spacer block, a block to hold two bearings, with
a
washer between the bearing and the spacer block. This allowed
the
bearing outer race to be pinched between the spacer block and
the
bearing block.
I made a new leadscrew, easy as I have a metric leadscrew,
and
turned
the shaft to be 2mm less in diameter than the original. I
also
made
the threaded portion approx 2" longer to allow more travel
for
the
Taig milling attachment I have.
This way I used smaller bearings and a sleeve between the
handle
washer and the bearings to clamp the leadscrew to the inner
race.
the original numbered dial fits over the sleeve and is held
in
place
with a set screw instead of the spring.
I sortof copied someone else's cross slide bearing mod, but
not
sure
where it was/is.
Here it is:
7x12-
Projects/Cross_Slide_Mod/
Bob.
