Hi Mike,
Yep, I think you've established the rear slide wears most but not
rapidly. I'm still planning to shim & lap my original slides like
you. I did forget the other major source of lifting forces on that
back slide - a traditional knurling tool being pressed into the work
via toolpost pressure. I take it you don't use one of those. :-)
John
--- In 7x12minilathe@..., Michael Taglieri <miket--
nyc@...> wrote:
On Wed, 07 Mar 2007 01:36:40 -0000 "born4something"
<ajs@...> writes:
There shouldn't be excessive forces. After all, the only load
bearing on that surface is when the carriage tries to lift -
usually
while using a milling adapter with the carriage stationary.
Gravity
works the other way.
Actually, this isn't quite true. There's a force lifting the rear
of the
carriage whenever the tool is cutting the outside of the work
(i.e., not
when making a facing cut). Therefore, you should expect the rear
to wear
more than the front on the bottom (and perhaps the front to wear
more on
the top).
When I lapped my dovetails and the underside of the bed in 2002, I
changed the gib retention system under the carriage to shims,
using the
original gibs. Within a year or so, the rear of the carriage got
a bit
loose and I had to take out 1-2 thousandths of shimming, but the
front
didn't need that treatment until late 2006. Obviously, this isn't
too
shabby, even for the rear, but I still expect it will always wear
more
than the front. If the underside of the rear ever wears to the
point
that some parts are looser than others, I can just relap the rear
of the
bed by sliding the carriage back and forth with abrasives on the
underside, after removing enough shims in the back so it drags
slightly.
Mike Taglieri miket--nyc@...
Everyone has his reasons.
- Jean Renoir "The Rules of the Game"
