CAD CAM EDM DRO - Yahoo Group Archive

Turcite "FAQ"

on 2000-01-13 05:07:27 UTC
Due to the number of people emailing me off list for more info on Turcite, I've compiled my collection of mails and posts into a
text file which I've been mailing out. It's a fairly small text file, so I'm including it at the end of this mail for anyone else
wanting the information for their archives.

Disclaimer: I've never seen or used the stuff. It was suggested that it would be suitable for my application, and so I've been
collecting information.

Marshall Pharoah
Software Engineer
Adirondac Software
PIC/6805/6811/68000/PowerPC
Asm/C/C++


The Unofficial Turcite FAQ

This document is a compilation of messages from the modeleng and
[CAD_CAM_EDM_DRO] mailing lists, and posts from the news group
rec.crafts.metalworking. I have tried to leave the posts mostly intact, but
I have removed quoted material from replies where that material was not
needed or applicable. I also left the headers intact so that the poster could
be identified for future questions/discussion.

Much of this is in response to a question I posted regarding a 13" South Bend
lathe I purchased for a ridiculously low price which showed noticeable bed wear.
I had remembered a discussion on RCM about a lathe bed grinder which ran along
the tailstock ways, but could find a trace of it in Deja News. The discussion
led to different methods of grinding the bed, and the application of Turcite
and similar substances to the carriage. I decided to go with the
reccomendation that I should set the lathe up as is, align it, and see how
much variation I could detect on a test cut. I still have not reached that
point, but I am very close.

Other parts of this are responses to general communications on the subject
which took place in late 1999, early 2000.

On to the major topic then:


Turcite Applications and properties:

From: Robert Bastow <teenut@...>
Subject: Re: Lathe Bed Grinder
Date: Thursday, October 14, 1999 12:29 AM

Turcite isn't really expensive in the small areas and thicknesses required for a
Southbend sized lathe. I doubt you need more than 6 or 10 square inches, and
1/32" or 1/16" maximum thickness. The epoxy they sell is pricy..but there are,
nowadays, other sources of epoxys that will do the job.

Re-furbishing a lathe with turcite ELIMINATES the need to drop the saddle or
raise the feed shafts etc. The Idea is to remove enough metal from the bed to
clean it up, and then mill enough off the saddle, not just to clean it up..but
to bring it back to exactly the same place it was when new...After you interpose
a layer of Turcite of the required standard thickness.

No scraping of the saddle is required! The Turcite and epoxy are alowed to
adhere and set, without applying any pressure and while the saddle is
temporarily shimmed to the right height and level. Once the Turcite has
adhered, then a very light spottin and scraping can be done..if required. If
the epoxying is done carefully...no "post scraping" should be required.

Applying Turcite will absolutely transform any lathe. Firstly it virtually
eliminates "stick/slip". Secondly, you can snug up the retaining gibs,
literally, to "negative clearance". That, and the natural tendancy of Turcite to
deaden vibrations, means that chatter will be virtally eliminated.

IMHO, having read, frequently of various ways that people have reground their
own beds, using a variety of ingenious, but convoluted methods..any accuracy
remotely approaching the accuracy of a new lathe..or a proper regrind..is PURELY
ACCIDENTAL!

I don't care how you care to figure it...using the tailstock ways to grind the
saddle ways because they are "less worn" than the saddle ways..is a crock of the
first order. However you run the trig..using a less than PERFECT guiding
reference to generate another one.will MULTIPLY, not decrease the original
errors!

Of course, when you have ground your ways until they look nice and shiny, and
you have twisted your lathebed so you can barely detect a taper (can you say
sway or swell?), then I guess it is easy to convince yourself, not to speak of a
casual, awestruck,observer, that you have indeed made it "as good as new"!

I wonder why Professional Rebuilders don't do it that way? They could bring a
portable rig and regrind your lathe bed while you nipped out to lunch. I bet
they just haven't thought of it yet, Huh? 8^)

A decent lathe deserves better..even if that means hand scraping the whole
thing. Of course then a decent set of scraping masters and references will case
more than a professional regrind.

teenut

From: Jon Anderson <janders@...>
To: <CAD_CAM_EDM_DRO@onelist.com>
Sent: Wednesday, January 05, 2000 10:50 AM
Subject: Re: [CAD_CAM_EDM_DRO] Turcite


Larry,

Turcite comes in a sheet form and requires a special adhesive. It also
requires that you can accurately machine the worn surfaces back by the
thickness of the turcite. I suspect the adhesive may allow some slight
alignment, but not much.
Another option is Moglice, a castable bearing resin. This requires that
one surface be restored true. For a lathe that would mean having the bed
ground. You'd have to machine back the ways in the saddle, glue small
pads of Moglice at each end of each way surface on the saddle, then
scrape these in until the saddle is properly aligned.
Apply release agent to the bed and trowel Moglice onto the saddle ways.
Place the saddle back on the ways and push until it seats on the
scrapped pads. Quickly recheck alignment, let it cure. After cure, you
can trim excess and machine/grind oil holes and channels. It comes in a
thick form to trowel in place or a thin form that can be injected with a
syringe. I've used it to cast nuts and once having some extra, quickly
set up and cast a plain bushing on some ground rod. That was the
smoothest plain bearing I ever felt.
I think Turcite would be better applied in a new fabrication unless you
are certain you can establish true surfaces to attach it to.

Jon




From: Robert Bastow <teenut@...>
Newsgroups: rec.crafts.metalworking
Sent: Monday, November 01, 1999 1:22 PM
Subject: Re: TURCITE - suitable adhesive??


Jack Erbes wrote:
>
> Dave and Sue Erickson wrote:
>
> <snip>
> > The reason for the post is that there is a third problem; the
> > table is about .001" too high in the front. My question: if
> > I plan on adding turcite, should I correct the .001" alignment
> > problem before or after adding the turcite? If after, will I
> > be able to scrape it using the same tools and techniques that
> > are used on cast iron, or should the scrapers be sharpened
> > differently, or different tools used?
>
> Bridgeport manuals say that the front of the table should be .0005
> higher than the back. They don't explain why, but I assume it allows
> for settling that occurs under load. Maybe your Hardinge needs
> something there for the same reason.
>
> --
> Jack in Sonoma, CA, USA (jack@...)

Jack is correct, the table should be a smidgin higher at the front than the
back..it takes account of weight and cutting loads plus eventual wear.

Sound machine tool design principal..the machine should get MORE accurate as it
wears...before it starts to deteriorate.

I would be tempted to leave the full 0.001" in there..ast least until the
machine has had time to bed in. Turcice will bed a bit further than cast ron
slides will..even they will do so to some small degree.

Should you feel the urge..Turcite is scraped with regular scraping tools..same
shapes and angles etc., but they do need to be RAZOR sharp or you will just
float over the surface as the turcite "dodges" out of the way.

If you know how to sharpen and use a cabinet maker's scraper, you will find that
better for evenly reducing large areas before final spot scraping.

teenut

From: Robert Bastow <teenut@...>
To: <modeleng-list@...>
Sent: Friday, January 07, 2000 10:36 AM
Subject: Re: Rebuilding using Turcite


Turcite (pron. turKite) is an extruded teflon based material with a
characteristic turquoise color.

Available in sheet strip and rod form, it has one side etched for epoxy
bonding to clean metal surfaces. It has much greater load bearing
properties than straight teflon, while retaining much of the low
friction..stiction free, properties.

Slide ways are best left with a cross ground finish..usually a portion of
the matching surface has to be milled or planed away to accomodate the
turcite..I have used both 1/16" and 1/32" with success. Careful calculation
allows one to completely recondition a machine slides without loosing the
original alignments. For example...measured maximum wear on both surfaces =
.020"..mill off additional .0425 from saddle surface...Add turcite .0625"
thickness..Leadscrew and shaft bearings on carriage and headstock still line
up properly!!

Not only does it provide a very SMOOOOTH feel to slideways..it has the
hidden advantage that gibs can be set with ZERO clearance..interference fit
even..and will still function effortlessly. Not only does this lead to
enhanced accuracy but an absolute dampening of vibration and the attendant
chatter.

The Hardinge HLVH Toolroom Lathe is fitted with Turcite or similar material
on the bed/carriage slideway surfaces.

The material is impervious to corrosion..which "Kills" more machine tools
than outright wear!! It can be run dry..or with minimum lube.

Finally, it is too soft to act as the base for lapping action..abrasive
partices simply disapear into it.

Lovely stuff!!

See...http://wearrings.com/prod/ep10a.htm

teenut




From: Larry Van Duyn <lvanduyn@...>
To: <modeleng-list@...>
Sent: Friday, January 07, 2000 11:38 AM
Subject: Re: Rebuilding using Turcite




Robert Bastow wrote:

> Try this link:
>
> http://wearrings.com/prod/ep10a.htm
>
> Robert Bastow

Hello Robert...

I looked at that link before and was trying to make some
sense out of their load figures.
1300 lbf/m squared ????
Do you have a good source for obtaining the material ?
The only quote I have gotten so far is $120 for a square
foot of .062......
Larry..


From: Larry Van Duyn <lvanduyn@...>
Subject: Re: Rebuilding using Turcite
> I looked at that link before and was trying to make some
> sense out of their load figures.
> 1300 lbf/m squared ????
It's a typo. Someone has read "in" as an "m", easy to do if you aren't
thinking or aren't looking too carefully (or don't know and are copying
someone else's script). My OCR software often reads "in" or "rn" as an "m"

9N/Sq mm = 9,000,000N/Sq m = 9E6 Pa = 1300 Lbf/Sq in, according to my
conversion tables
Regards
Tony
Tony Finn
Hedon, Hull, East Riding of Yorkshire, England
<tony@...>
Website: <www.finn-aj.freeserve.co.uk>
"Plus �a change, plus c'est la m�me chose!...."
(The more things change, the more they stay the same!)



Turcite, Adhesives:

From: Robert Bastow <teenut@...>
Newsgroups: rec.crafts.metalworking
Sent: Thursday, October 28, 1999 2:33 PM
Subject: Re: TURCITE - suitable adhesive??


I wouldn't rely on it for material less than 1/16" thick and I have no
experience of anything as thick as 3/16". Bearing in mind the tendency for
these type materials to cold extrude, I would be wary of it..and of using screws
through it. Knowing my relationship with Murphy (He has it in for me as I have
challenged and cheated him far too many times!!)..I would Expect the screwws to
come in contact with the ways eventually!!

What I HAVE done is to use the aformentioned double sided tape simply as a means
to hold the turcite in place during fitting and assembly. Eventually cutting
oil etc will degrade it to zero effectiveness. Howerver, by adding retainer
lips, just like and incorporatin wiper seals, the turcite is trapped with no
place to go.

Before Turcite, the only teflon alternative was pure white teflon. Many machine
tools..especially NC and CNC HAD to use teflon to overcome the bugaboo of
stick/slip. In those cases, with glues simply not available, the manufacturers
used mechanical means of retention..the main one being as I detailed above..with
entirely satisfactory results.

Turcite and other teflon based slideway materials offer several advantages, some
of which may not, immediately obvious:

Reduced friction and massively reduced stick/slip differentials (The ratio
between static or "stuck" frictional coefficient and dynamic or "slip"
coefficient, are probably its best known and understood advantages.

Others include; Reduced sensitivity to lubrication (or rather, lack of it).
Reduction of wear on slideways..teflon tends to simply "swallow" abrasive
contaminate particles rather than simply holding the at the surface to act like
a lap.

Reduction of chatter..teflon tends to act as a damper.

To me, however, one other feature is, in itself, worth all the effort. This is
what I call "Zero Clearance slideways

Hard metalic slideways always need a minimal clearance to opperate..without a
thou or two of carefully adjusted clearance, they become "clamps" rather than
slides. Any wear, taper or other inaccuracy of the sliding surfaces makes this
controlled clearance difficult or impossible to set and maintain.

With resiliant, low friction teflon lined slides the need for clearance is
ZERO..indeed I set up slides, whenever possible with NEGATIVE clearance..a clamp
arrangement even!! The low friction material makes a lousy clamp though..so the
result is a slide without ANT wobble or shake, and which can accommodate quite
large degrees of wear or taper.

The difference this makes to the "Feel" of the machine and the accuracy and
improved surface finish obtained, have to be experienced to be truly
appreciated. As a bonus, given adequate power, the depth of cut and feed rates
can often be dramatically increased..Chatter is a thing of the past!

8^)

teenut



Turcite, Sources:

Note: I don't know where this link came from, or if it applies, but it
was with the rest of the Turcite archive:

http://www.u-cups.com/prod/ep10a.htm



From: Tim Goldstein <timg@...>
To: <CAD_CAM_EDM_DRO@onelist.com>
Sent: Thursday, January 06, 2000 12:01 AM
Subject: RE: [CAD_CAM_EDM_DRO] Turcite


Try http://www.belzona-western-ltd.com/

> -----Original Message-----
> From: Steve Carlisle [mailto:quatsein@...]
> Sent: Wednesday, January 05, 2000 9:47 PM
> To: CAD_CAM_EDM_DRO@onelist.com
> Subject: Re: [CAD_CAM_EDM_DRO] Turcite
>
>
> Jon, Belzona is a company in North America that
> sells specialized resin products. That may not be
> a very good explanation of what they sell. For instance
> they sell to large mining companys a product for
> casting in place bearings to replace metal bearings
> that are on the hinge for dump boxs on huge mine
> haul trucks. They are on the web somewhere.
>
> Steve
>





From: Bruce <TRAINHEAD@...>
To: <modeleng-list@...>
Sent: Thursday, January 06, 2000 2:45 PM
Subject: Re: Rebuilding using Turcite


Anthony and others,

Turcite is available thru my plastics supplier, Ain Plastics Inc., 249 East
Sandford Boulevard, PO Box 151, Mount Vernon, N.Y. 10550 Phone
1800-431-2451. In NY 914-688-6800
Available in Turquoise color (Turcite A) and red (Turcite X)
Type A 1/4" diameter@ $2.80 per foot thru 4" diameter @ $158.00 per foot
Type X 1/2" diameter @ $5.50 per foot thru 2 1/2" diameter @ $103.25 per foot

AIN Plastics does have a $50.00 minimum but that will easily be met if your
buying this stuff.

>And last question, where do you get the stuff and what are the size options?
>




Bruce Mowbray
trainhead@...
http://www.geocities.com/trainhead391/
TMB Manufacturing and Locomotive Works
1 1/2" Scale & 2 1/2" Scale (Narrow Gauge) Live Steamer






From: Robert Bastow <teenut@...>
To: <modeleng-list@...>
Sent: Friday, January 07, 2000 10:16 AM
Subject: Re: Rebuilding using Turcite


Try this link:

http://wearrings.com/prod/ep10a.htm

Robert Bastow








Moglice:

From: Mike Rehmus <mike@...>
Newsgroups: rec.crafts.metalworking
Sent: Friday, October 15, 1999 11:29 AM
Subject: Re: Lathe Bed Grinder-Moglich


The nifty stuff is called Moglich (sp?), a pourable epoxy version of
Turcite. You wedge the carriage up to height on bits of Turcite and then
pour this stuff in. Makes a made-to-order Turcite-lined carriage. This is
the way they build some new machine tools (large ones), especially on-site.




From: Leslie Watts <leswatts@...>
Newsgroups: rec.crafts.metalworking
To: Greg Nuspel <nuspelg@...>
Sent: Wednesday, October 20, 1999 2:38 PM
Subject: Re: Lathe Bed Grinder-Moglich


M*glice machine repair compound:
http://www.connix.com/~mogoreh

ITW Philidelphia resins Super Alloy for machine repair and design:
http://www.phillyresins.com/sa.htm

I won't pretend to not be biased :^) but you be the judge. We also
make a line of polymer concrete for casting large parts like machine
bases, pourable damping compound for precision machine chocking,and
wear resistant ceramic coatings for machine parts.

--
Leslie M. Watts
ITW Advanced Technology Group
(847)657-4559
http://www.netcom.com/~leswatts/leswp.html







From: Russ Kepler <russ@...-eng.com>
To: <modeleng-list@...>
Sent: Friday, January 07, 2000 11:37 AM
Subject: Re: Rebuilding using Turcite


An alternative to Turcite is Moglice. One nice thing about Moglice
is that it's castable, so there's no need to machine more off is
necessary to return to a reference surface (you put it on the smaller
of the 2 surfaces and return it to the appropriate centerline). If I
remember right Jon Andersen (from the group) used it to rebuild the
nut on a leadscrew, and found it a very nice product to use.
Apparently, Clausing uses it in new machine construction as well, so
it's not limited to use in rebuilds only.

Moglice contains (from memory) Teflon and moly-disulphide. You can
see some pages from a rebuilder who uses it at
http://www.connix/com/~mogoreh

--
Russ Kepler russ@...

Please Don't Feed the Engineers

Discussion Thread

Marshall Pharoah 2000-01-13 05:07:27 UTC Turcite "FAQ"