RE: [CAD_CAM_EDM_DRO] Sherline CNC retrofit

If you do that make sure you use a non embedding type grinding compound
such as Timesaver. Otherwise the grit will embed and keep on cutting.
Dan
-----Original Message-----
From: Bill Vance [mailto:ccq@...]
Sent: Tuesday, December 10, 2002 10:53 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] Sherline CNC retrofit


Yo Jan;

The next time you make one of these, you might try something a friend
advised me to do on the ways. It might just be the berries for your z
axis. He said to spread a very fine abrasive suspended in oil on the
ways, and run them from end to end numerous times, adjusting the gibs,
and adding more abrasive/oil, until the travel became glass smooth from
end to end. Clean it all off, and replace with just way oil. A bit
time consuming, but worth while, for ways/gibs, and possibly, your z
axis.

Just a thought.....

Bill

On Tue Dec 10 21:26:58 2002, JanRwl@..., <JanRwl@...> wrote:

>OK, Gang! Bill says go ahead, so...
>
>Backlash and lead-screws: First, gawk at Photos in Album #17 (first
>Album on
>p.2 of PHOTOS). I grant you these snapshots were NOT made with the
intent of
>showing details of the lead-screws, per-se, but these two items WERE
100%
>home-brew. Now the lathe, as you can see, is controlled by a Tandy
1500HD
>(1991!) laptop running MSDOS GWBASIC. NO mouse nor Windows nn! (See
further
>comments on electronics below!)
>
>As I had built an earlier similar lathe in '84 using a
>long-discontinued CBM
>PET (which also is still going, in use!), I already had a "feel" for
BSA's
>ACME lead-screws and their Turcite nuts. This is a
fiber-glass-impregnated
>PTFE plastic, so it has "controlled" friction and is sturdy. However!
The
>fiberglass in it has a peculiar property! For my use of this machine,
most
>of the "Z-travel" (that'd be "X-travel" in Cartesian-speak!) is within
the
>same 4", so that portion of the lead-screw where the Turcite preloaded
nut
>bears over that part of the screw is highly-polished, and the friction
there
>is NOTICEABLY less (when the screws' handwheels are turned by hand,
>stepper-windings OFF). That is, the glass fibers impregnated in the
Turcite
>act as "potted abrasive", and have actually POLISHED the screws in that

>portion!
>
>These screws are 4 mm/turn ACME, 20 mm dia., stainless steel. Those
>Turcite
>nuts (bright red plastic) are made in TWO halves, each of which have
two "90°
>wide" fingers which, when properly meshed as they are sequentially
screwed
>onto the screw-stock, "lock" one-another so that if either turns, the
other
>must follow; no angular "play" between them. Then, a rather heavy
>coil-spring fits between these two halves, pressing them apart, so one
half
>presses on the "right side of the threads" and the other half presses
against
>the "left side of the threads". ONE half is also externally threaded
so that
>it screws into a black-anodized aluminum flange-ring which makes
bolting the
>whole assembly to the mechanism (in this case, the "saddle" of the
lathe).
>
>Now these screws and nuts are BSA products, and are fine stuff, if
>pricey.
>But all considered, having these lead-screw parts made by a good
job-shop
>charging, say, $75-$150 per hour would cost at least twice as much,
assuming
>it would even be POSSIBLE to get the same quality/consistency.
>
>The "friction load" of these nicely-hefty nuts on the 20 mm. dia.
>screw-stock
>is much more than one would like to have on any kind of
manually-operated
>lathe's lead-screws, but the hefty BIPOLAR Size-34 steppers clearly
don't
>care at all! So, with no "play" (aka "backlash"), and steppers which
manage
>fine, this is a "slop-free" arrangement.
>
>I built this lathe simultaneousely with a "twin" which got shipped to a
>customer in Ohio (he supplied is own laptop) in the latter quarter of
'99. I
>had not yet heard of Gecko, and though everything is working perfectly
on
>both machines, I perhaps wish I had, as I would have saved considerable

>$heckles using the G210 drives (were they available in '99?)! I used
"black
>boxes" by the stepper-manufacturer, Superior Electric. These "black
boxes"
>contain TWO bipolar-chopper drives AND a 120/220-240 VAC-to-DC
power-supply
>which have opto-isolator inputs, "All Windings OFF" inputs (to remove
DC from
>the motors for set-up, etc.), and a sturdy "important-looking" box.
The only
>"electronics" left for me to do was to build a simple
"buffer-interface"
>between the laptop's "printer port" and the opto-isolator inputs on the

>stepper-drive box. I used a 74HCT541 Octal non-inverting buffer, a
pair of
>74HC4538 monostables to "set the pulse-width", and a ULN2003 Darlington

>driver to "light up" said opto-isolators. OH, I had to make a tiny
5VDC
>supply for that, as this laptop did not have a USB nor "game-port" to
supply
>the +5VDC.
>
>The first two bits of the parallel-port are for "Z", the next two for
>"X" (on
>a lathe, "left-right" is the Z axis, and "north/south" is the X axis.
There
>are more than one "Now, lessee..." stories as to how that came to be,
and I
>must admit I use standard Cartesian "X" for East-West, and "Y" for
>North-South, but DON'T TELL ANYONE!. Then the next two bits are XOR'ed
to
>operate the electropneumatic (100 psi "shop-air") tail-stock valve, and
the
>final two bits are XOR'ed to operate the spindle-motor SSR's.
Three-phase,
>so three SSR's!
>
>These Superior Electric "black boxes" are their series "SS2000---"
>They cost
>me over $700 each. I am sure I could have built power-supplies for
$20, and
>a pair of G210's would have been less than $300. So, I could have
saved over
>$350 per lathe, had I only known of Mariss' fine product! But the
SS2000
>things work fine, so... One thing it took me a day or so to "get
over": I
>had built several stepper-motor things using old UNIpolar systems with
big,
>hot "L-R ballast resistors", so I had a subconscious "need" to think
the DC
>supplies had to be able to supply the "rated current" to the motors.
That
>is, if each of two windings wanted 4 amps, two motors, the DC-supply
would
>have to supply 16 amps. But with Bipolar Chopper Drive, if your
supplies are
>going to be six times the "motor voltage", they need supply only a
fraction
>of the CURRENT, as no power (that's Watts!) is wasted as HEAT in those
>ballast resistors! So, for two Bipolar motors rated at 3.5 amp per
winding,
>you would need NOT 14 amps, total, but only about 3 amps, total!
Really!
>Blew me away when Mariss explained this to me in an e-mail about a
season
>ago!
>
>Jan Rowland
>
>
>[Non-text portions of this message have been removed]
>
>
>Addresses:
>FAQ: http://www.ktmarketing.com/faq.html
>FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
>Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
>
>Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
>Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
>List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...
>Moderator: jmelson@... timg@... [Moderator]

>URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
>OFF Topic POSTS: General Machining
>If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it
if you have trouble.
>http://www.metalworking.com/news_servers.html
>
>http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there,
for OT subjects, that are not allowed on the CCED list.
>
>NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING
>THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
>bill List Mom List Owner
>
>
>
>Your use of Yahoo! Groups is subject to
>http://docs.yahoo.com/info/terms/
>
>
>

--
------------------------------------------------------------------------
----
RKBA! ***** Blessings On Thee, Oh Israel! *****
4-19!
----------------+----------+--------------------------+-----------------
----------------+----------+--------------------------+----
An _EFFECTIVE_ | Insured | All matter is vibration. | Let he who hath
no
weapon in every | by COLT; | -- Max Planck | weapon sell his
hand = Freedom | DIAL | In the beginning was the | garment and buy
a
on every side! | 1911-A1. | word. -- The Bible | sword.--Jesus
Christ
----------------+----------+--------------------------+-----------------
----------------+----------+--------------------------+----

Constitutional Government is dead, LONG LIVE THE CONSTITUTION!!!!!

------------------------------------------------------------------------
----

Addresses:
FAQ: http://www.ktmarketing.com/faq.html
FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com

Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...
Moderator: jmelson@... timg@... [Moderator]
URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO

OFF Topic POSTS: General Machining
If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it
if you have trouble.
http://www.metalworking.com/news_servers.html

http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there,
for OT subjects, that are not allowed on the CCED list.

NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill
List Mom List Owner



Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/