Hi Roy,
Combining these ideas, an offset adjuster as detailed at LMS could
be made with a graduated scale as well as provision for a socket
wrench on the end. Say an M6x1 bolt and major graduations every 9
degrees, minor ones every 0.9 degrees if you're keen. Then you turn
a bit at each end of a test bar and mike it to determine the current
offset, tweak the adjuster using the graduated scale and eureka! Of
course, you'de re-check with the test bar the first few times at
least...
John
--- In 7x12minilathe@..., "roylowenthal"
<roylowenthal@...> wrote:
Another approach to aligning the TS is to turn a test bar between
centers to measure the misalignment, then adjust the TS off the
lathe. Unlike on larger machines popping the TS off is effortless
and it allows access to the underside locking screw. To move it
controllably, use a depth mic (or a depth base on a dial caliper)
to
measure the original position of the upper part relative to the
base. With a measuring tool involved it's easy to get it into
final
position without having to make an adjuster.
The boring head is used to hold a short center an easily
adjustable
distance away from the lathe centerline for taper turning without
disturbing the TS adjustment. The downside is losing a couple of
inches of working length on the lathe.
Roy
--- In 7x12minilathe@..., "wrlabs" <wrlabs@> wrote:
Hi Bruce,
Thanks for the response!
--- In 7x12minilathe@..., "Bruce Leo Hartmann"
<goodsnout@> wrote:
Hi Vikki
Oops, sorry about misspelling your name. I should have paid
closer
attention. (I do suffer from ADD and dain bramage.)
LOL, anything but late for chow :). I probably didn't notice
for
the
same reasons ;-).
6-32 is a good "starter size" because if this size proves to
be
too
small or weak for the job (at times I've had to put a lot of
torque on
the Tee wrench to get everything perfect on a particular job)
it
will
be very easy to move up to an 8-32 then 10-32 screw size due
to
the
common thread pitch; however, 6-32 is VERY course which makes
this
size one of the more difficult to cut without breaking a tap.
10-32 sound like a better idea, I just had some of the stainless
6-
32s
from an antenna project left over. No real biggie to go get
some
at the
local Ace Hardware.
(Breaking a tap will really ruin your day. 10-32 will prove to
be
a
much easier size to tap without breakage. That said, cast iron
tends
to be an easy material to tap.
I'll be gentle :-). Actually, I am still leery of hacking into
the
machine, but getting more open about it over this whole tailstock
experience. Hopefully doing the cam lock mod will get me over
it.
If you go with 10-32 you'll soon
discover that your 4mm metric Tee driver fits the screw head
better
than the 5/32" wrench that 10-32 SHCS's were designed to take.)
Remember that stainless "steel" really isn't steel (it's
stainless
iron) and not as strong as your standard black (usually grade
5
or 8)
SHCS's. This is especially true of common 300 series (non-
magnetic)
stainless fasteners.
Not sure what Ace has (easiest to get to in the traffic quagmire
in
Seattle), but will check.
I've never done a camlock conversion although this
particular
upgrade will make life much easier. Instead I simply cut a 17mm
combination wrench in two. I use the box end (which is slightly
offset) for tightening my tailstock nut. (My tailstock nut is
a
10mm
acorn nut.) The offset box end combined with the acorn nut
makes
adjustments "fairly" easy. I was all set to make life much
easier
and
convert to a camlock but before this happened (I kept putting
it
off)
I had occasion to drill some very large holes using the
tailstock
chuck. I discovered that unless the tailstock base nut was
VERY
tight,
I would get some tailstock movement/slipage. You can get the
tailstock
locked down much tighter using a wrench. (The threading on the
base
screw gives you more mechanical advantage than a cam.) If you
never
drill holes larger than 1/2", slippage shouldn't be much of a
concern
with a camlock.
I don't have a drill bit bigger than 1/2" and if I did I'd have
nothing
to hold it :-(. I figure for anything bigger I use boring bars.
Trying to tighten the tailstock with a straight open
end wrench (like the one that came with the lathe) WILL drive
you
nuts
quickly.
Noticed that :-), but it was a short trip from where I was :).
I've
got a 17mm combination on there and if it was cut in half it
would
indeed be much more tolerable (only "good" one I have).
The reason the camlock is so popular is not becasue it saves
your wrist and hand but because it's SO much more accessable.
You
don't have to worry about those tricky tightenings when you
have
to
work around (under) the cross slide dial. This is where having
an
offset 12 point box wrench makes things easier but not quite
as
easy
as a camlock.
Sigh, so many variables here. Possibly to remove the cam lock
and
use
the nut in anything critical I would think. Better an
occasional
PITA
than a full time one :).
I would only make the LMS tailstock adjuster (your included
link)
if I had to often offset the tailstock to cut long tapers. This
modification will make it much easier to move the tailstock by
minute
amounts but you'll still have to cut test pieces to make sure
your
adjustment is perfect. Of course once you get the tailstock
adjusted
to zero taper (using any method), you'll likely want to mark
the
upper
and lower parts of the tailstock (straight chisel mark, two
punch
marks or a scribed line) so you can get back to zero (or near
zero)
quicker if you do offset the tailstock to cut a long taper.
So far I have no need / desire to cut tapers (I seem to be doing
it
just
fine though LOL), but I am sure that can change although just
what
that
would be for I have no idea at the moment.
I got the thing aligned last night (I think), zero top and
bottom
and
around 0.0005 front to rear. It is the ~0.003 I am getting on
the
quill
outside that perplexes me, would seem that if the DI is showing
that
tiny deviation I should not be having the tilt in the quill?!??
Or
at
least that much. Perhaps I should mike the outside of the quill
to
be
sure it is not tapered (slow, but we get there :-).
Now I need to find out what color they used to do touch ups on
the
tailstock. Was surprised that the little nylon hammer could
chip of
that much paint with so little force :-(.
It has been an exciting exercise in understanding what is going
on
in 3D
space :).
I put off pulling it out and tightening the lock SHCS on the
bottom
for
today, I wanted to be sure I was well rested before taking that
one
on,
I just hope I get it right the first time and don't jar it out
and
have
to start over, although it will be easier next time :).
Unless you
need as much space as possible between centers it will be much
easier
to do longer tapers (i.e. too long to use the compound) by
mounting a
boring head in the tailstock.
Err, I thought boring stuff was for inside things? I think I am
missing
something here?!?
Thanks & take care, Vikki.
