Subject: Glass Saws

From: Jim Jaskie <[email-masked]>
Date: Tue, 13 Sep 1994 00:04:52 GMT

Hello everybody.  A few months back there was a thread about bandsaws
made for cutting glass.  I read it with mild curiosity as I am unfamiliar
with such things, but I didn't pay attention because "I don't need such
things."  And as everyone over thirty just guessed, now I need to know
such things.  Life never gets dull!

I (we) need to be able to machine glass easily.  We've bought a
sophisticated saw similar to a radial arm saw for cutting glass, but we
also need the equivalent of a bandsaw or even a Bridgeport Mill. 

The thread talked about a 'bandsaw' that used wire and an abrasive grit
to cut glass.  "Does anyone here recall, or remember at all" the
manufacturer of the bandsaw?  I've looked in the FAQ before asking
(wouldn't dare do otherwise!  ;>) ) but I did not see anything (yeah,
yeah, I know I must be becoming blind).  Can anyone help?  Anyone know
who makes such toys?

Thanks for any help that you can give.

-jim

---------------------------------------------------------------------
"No man, woman, or child is safe when Congress is in session." Will Rogers

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From: [email-masked] (CMHunt)
Date: 13 Sep 1994 00:23:04 -0400

>yeah, I know I must be becoming blind).  Can anyone help?  Anyone know

I don't know about the previous thread, but I saw several different saws
in a catalog that I got from Contempo Lapidary Equipment. Their address
and phone is:  12273 Foothill Blvd. Sylmar, CA  91342 (818) 899-1973.

They have two different band saws with diamond blades and a scroll saw you
can buy a separate diamond blade for.  

Hope this helps.  

CMHunt

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From: [email-masked] (Pete Bellas)
Date: Tue, 13 Sep 1994 16:11:28 GMT

Does anyone know what the finish level is on precision ground flat stock
(that is in terms of grit). I am finishing out some knives/tools that I
ground from some PG O-1 tool steel, but every time I hit them on the buffer
a few of these original longitudinal "grind" marks show up. Perhaps I need
to go back and regrind at a lower grit?

			-Pete-

* Pete Bellas                   "Cogito ergo spud"                         *
* Citicorp/TTI                       I think therefore I yam.              *
* Santa Monica, CA                                                         *
* [email-masked]                                                     *

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From: [email-masked] (Tim Kirby)
Date: 13 Sep 94 09:00:33 CDT

Jim Jaskie ([email-masked]) wrote:
: ...And as everyone over thirty just guessed, now I need to know such things.

Ain't it the truth. I hate when that happens.

Jim Kirkpatrick keeps an archive of r.c.m ... (from the FAQ)

>   I also keep an "informal" archive of the newsgroup on plains.uwyo.edu,
>   also in the METAL directory.  It's informal in that I only update it
>   from time to time, not continuously.

You may  be able to find what you need in there...

Tim
--
Tim Kirby _________ Cray Research Inc., Eagan, MN, USA __________ [email-masked]
Software Division              System Support                +1-(612)-683-5390
__________________________ Consider it disclaimed ____________________________
If all else fails, Immortality may always be assured by spectacular error(JKG)

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From: [email-masked] (James Kirkpatrick)
Date: 13 Sep 94 09:11:36 MDT

The original thread on glass-cutting saws dates from November 30 1993.
If you'd like, you can ftp the entire 1993 archive from plains.uwyo.edu
in the METAL directory, and browse around.  Here's a summary:

Subject: Glass Cutting Saws?

From: [email-masked] (John De Armond)

Yes, we have a Diamond Lazer 1000 saw which is a chinese clone
of the Gryphon unit.  It works very well and we are quite
pleased with it.  It's speed is dependent on the thickness and hardness
of the glass.  For thin fusable glass (what I usually use it with), it
cuts several inches per minute.  Even regular stained glass cuts
satisfactorilly fast.  It is NOT as fast as scoring-and-breaking but
then again, you can't score a spiral or other complex shape.

My experience is most stained glass dealers disparage the products
they either can't get or don't make money on.
 ...
The Gryphon saw was cloned because their price was so outrageous.
Strangely enough, Gryphon's saw is now reasonably priced.  We paid
about $200 for our saw.  I have used several other brands including
the very expensive german unit and I like the Lazer the best.
It is fast and deceptively rugged.  Accomidations for the diamond
blade are subtle but numerous and range from the tensioning system
to the rubber rollers and teflon guides.
 ...
Sawing really isn't a substitute for pieces that can be scored and
cracked.  The speed of scoring is vastly superior.  On the other hand,
if you have a curved cut on a $50 piece of glass, it is nice not to
risk a spurrious crack.
 ...
The pantograph-based scoring machines work well.  Gryphon makes a fairly
expensive scoring machine that seems to have some merit.  IT has a
pneumatic driven scoring wheel and a variable speed rubber drive wheel
under it.  The idea is to feed the glass in much as you would to a band-
saw.  The score is deep and accurate.

I am investigating having diamond blades made for a Delta woodworking
saw but I've yet to find a suitable price.  The conversion requires
more than just the blade.  Things such as rubber rollers and
frictionless guides as well as a water system.

I'm experimenting with CO2 laser cutting but the work is in its earliest
stage.  It looks to have some possibilities.

BTW, there is a stained glass mailing list, [email-masked].  Subscribe
to [email-masked].  Put your email address on the Subject: line.

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

From: [email-masked] (johnm)

> I saw a post in rec.crafts.misc (I believe) about a year ago from
> someone who seemed very pleased with a stained glass cutting band
> saw.  However, I!ve talked to a few glass dealers who claim that
> they cut very slowly (one inch/minute) and really aren!t worth it
> unless you need to make very integrate cuts which would be
> impossible to do otherwise.
>

I agree with the glass dealer. I have not seen the bandsaw but I have
seen many glass saws. The problem is class can not be cut a we think of
it from having experience with things like wood or plastic. That is why
most glass is cut by scoring. Some very intricate cuts can be made with
scoring, check out a stain glass expert. Glass cutting with a saw is a
grinding process. Typically diamond abrasives are used. Since the volume
of cut material is removed in powder instead of a chip the processes just
can not be too fast with causing high stresses in the glass.

Bandsaw blades wear as the revolve due to the bending around the wheels.
Priced any diamond blades lately? My 7 1/4 circular saw blade cost over
$100. I am sure the bandsaw blade would cost much more. In fact if I made
the bandsaws I would give the user the saw as long as I could sell him
the blades!!

My advice is figure out what it is you really want to do. See is the more
traditional cutting methods could be used. Then price the cost of having
it cut by someone who owns the equipment.

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

John strongly rebutted:

>I agree with the glass dealer. I have not seen the bandsaw but I have
>seen many glass saws. The problem is class can not be cut a we think of
>it from having experience with things like wood or plastic. That is why
>most glass is cut by scoring. Some very intricate cuts can be made with
>scoring, check out a stain glass expert. Glass cutting with a saw is a
>grinding process. Typically diamond abrasives are used.

There is a certain danger in posting about things one has no experience
or first hand knowledge about.  Perfect example.

The diamond bandsaw cuts glass through a combination of abrasion and
spalling.  The chips removed from the stock are much larger than the
grit of the blade (as you would have known had you ever actually
used a diamond saw.) and therefore the cutting speed is much faster
than what could be achieved by abrasive action alone.

>of cut material is removed in powder instead of a chip the processes just
>can not be too fast with causing high stresses in the glass.

This is absolutely false.  Indeed, quite the opposite is true.  I have a
homemade glass slicing saw that uses a thin 2" diameter diamond blade
rotating at 25,000 rpm.  That is, a rim velocity of (2*pi*25000) =
157,000 feet per minute.  This saw is as smooth as silk and cuts glass
about as fast as a radial arm saw cuts an equivalent thickness of wood.

>Bandsaw blades wear as the revolve due to the bending around the wheels.
>Priced any diamond blades lately? My 7 1/4 circular saw blade cost over
>$100. I am sure the bandsaw blade would cost much more. In fact if I made
>the bandsaws I would give the user the saw as long as I could sell him
>the blades!!

Home Depot sells a 7-1/4" diamond blade for $60.  Irrelevant.  The blade
for my diamond band saw costs $40.  In the two years we've owned the saw
which has been in almost daily use, there has been no discernable wear.
I have broken the blade a couple of times but it is a 10 minute process
to silver-solder it back together again.  I recently received a notice
from the company that makes the blade.  They announced a new stainless
steel substrate blade for $40 and a price cut to $20 for the soft
metal substrate blade.  They describe the stainless steel blade as a
lifetime blade.  I believe it.  Somehow I don't think the saw maker
would give away a $200 saw in order to sell even one $20 blade.

In general, diamond abrasives are as cheap as others and are getting
cheaper.  I buy most of my diamond abrasives from the Truebite corp
in New York.  Drills and burrs suitable for use in a dremel tool
costs typically $7.  A 4" diamond hole saw to be used in a drill
press costs all of $60.

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

From: [email-masked] (DRAGON!)

>  I would also suggest that a band saw might be very unsatisfactory,
>but weakly suggest looking at wire abrasive saws  either diamond
>or "mud" as in silicon carbide water slurry.  The things you can not
>do by scoring and breaking like holes, internal cut outs can be
>tackled with careful wet use of abrasives.  Wet grinding is a
>safty feature as well as keeping things cool.    Les DeGroff

Just FYI, not a flame, the bandsaws for Stained Glass are like wire abrasive
saws . . . diamonds on the cutting edge.  I believe they've all got water
baths built in as well.  SG grinders all have water baths for cooling/
cleaning.  The one area I've found that takes some work is when I'm trying
to drill holes with the smaller tips.  That requires stopping to wet the bit/
glass periodically.  For holes Black & Decker sells a 4 bit set of tile/
glass drilling bits.  I've got a set but haven't tried them.  They too, will
need to be cooled with water or something.

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From: [email-masked] (John Morton)
Date: 26 Sep 1994 14:22:34 GMT

In article <[email-masked]>, PAUL  <[email-masked]> wrote:
>about the best finish you can expect on "precision ground" steels from any mill
>is a 32 microfinish. also, dont expect edges to be square to each other (they
>never are) and the steel companies have some ridiculously liberal tolerances
>for flatness (lik
>e +- 1/32 per foot) Basicly flat ground stock is a waste of money, unless you
>have a customer that places some value upon it's use!

The Starret ground stock I have always found to be quite good.  They offer
+/-.001" on the thickness.  I'm not sure about straightness, but I have never
seen a piece that was visibly not straight, nor edges which were badly out
of square.  Starrett specifies 35 um. finish, I believe.

Of course one should never count on bought material to be anything better
than the manufacturer claims it to be.  

John Morton					University of California
[email-masked]			Mechanical Engineering
{decvax,cbosgd}!ucbvax!euler!jmorton		Machine Shop

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From: PAUL <[email-masked]>
Date: Mon, 26 Sep 94 21:43:54 -0500

>of square.  Starrett specifies 35 um. finish, I believe.
 
Let me elaborate...The steel companies get oversized low carbon CRS and slap
each of the 4 sides on a magnetic chuck grinder and grind it to dimension. The
squareness of this material (1 se to the next) is never better than the
squareness of the original material was. I can agree that Starrett does about
the finest job you can find. It was my intention to point out that this shou
ld be taken into account for the particular purpose you have in mind. as for
flatness, visibly straight is a term that carpenters use!

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From: [email-masked] (Dave Golber)
Date: 27 Sep 1994 16:27:53 GMT

In article <[email-masked]> PAUL <[email-masked]> writes:
>ld be taken into account for the particular purpose you have in mind.

I'd like to understand better:

It seems to me that:

(1) Grind one side flat (to tolerances of grinder)

(2) Turn over.

(3) Grind other side flat to within tolerances of the grinder.

So the opposite sides end up parallel within the tolerances of the grinder.

The squareness then depends on how they do the next step.  Either

(a) Just put it down flat on one unground side and grind the other unground
side.  Then you get no more squareness than the original stock, or

(b) Clamp it against one of the already ground faces.  Then you get
squareness determined by the clamping arrangement and the precision
of the grinder.

Any comments?

Dave Golber

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From: [email-masked] (John Morton)
Date: 27 Sep 1994 17:29:33 GMT

>flatness, visibly straight is a term that carpenters use!

What, so I'm a carpenter?  :-)  I'd like to point out that you can easily
see deviations from straightness of less than .001" by holding the piece
against a surface plate or a straightedge.

You are correct in saying that the purpose will guide your selection of
stock, and one should certainly not buy ground stock expecting to use it
as parallels, for example.  In the shops where I've worked, Starrett ground
stock was just a good way to get small amounts of tool steel.  There are
enough good surfaces to put you well on your way to the finished part.
However all these jobs went into the furnace, where you lose whatever
flatness you were fortunate enough to get.  The finish grinder is what
makes the part.  (I had overlooked the fact that mild steel ground stock
is available - I've never used it.)

BTW I can suggest a wonderful project for any shop with a surface grinder:
a set of 1/16" thick parallels in every 1/16" of width from about 3/8"
to the height of your milling vise jaws (~ 1 3/4").  I use mine constantly
when using the mill, and wonder how I got on without them.  The fun part
was quenching them.  It is very difficult to avoid distortion in a 
slender piece, so I wound up quenching them between ground steel blocks
the size of bricks.  I made a rack in the furnace to hold all the pieces
in such a way that I could grab one with tongs and slap it onto a brick; 
then my accomplice would slap another brick on top of it.

This quenching method is very effective - you could touch the parts within
a few seconds, and they were fully hard when tested.

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From: [email-masked] (Joe Landau)
Date: Wed, 28 Sep 1994 05:19:12 GMT

>then my accomplice would slap another brick on top of it.
Is it feasible for a rank amateur without a surface grinder to make a set of
parallels?

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From: [email-masked] (John Morton)
Date: 29 Sep 1994 17:28:16 GMT

>Is it feasible for a rank amateur without a surface grinder to make a set of

My approach to this would be to start by evaluating what you are able to
produce with whatever you've got.  What this means is measuring between
surfaces with your best measuring tool.  It is impractical to try for
better parallism than you are able to measure.

If you have an accurate milling machine in good condition you may be able 
to produce pretty good parallels.  Use indicators to monitor the movement
of the knee, and measure both ends of everything.  A worn mill tends to
send the table over a hump as it travels, which would cause your part
to be thinner on the ends.

You also cannot get a parallel part without either a parallel work surface
(i.e. the bed of the vise, or better, the mill table itself, working
against an angle plate) or shims down to .0005" to make corrections.

The big drawback to these parallels is that they will not be hard.
And if you harden them they will no longer be straight, and too hard
to cut accurately except with a grinder.  Oh well.  You can get pretty
cheap parallels (which are only pretty good).  I suggested the above
project because I have never seen a set like that for sale.