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:
Projects/Cross_Slide_Mod/
Bob.
