From: Robert Bastow <teenut@home.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: Dressing grinding wheels; Was: drill sharpening FAQ?
Date: Tue, 12 Oct 1999 19:21:45 GMT

mulligan@advinc.com wrote:

>
> Doggone.  We agree about *something*, Robert.

Oooh!

You walked right into this one Jim!! (I wouldn't be able to sleep tonight if I
didn't say it...)

"Maybe that's because you were correct about something,for a change!!!"

8^) 8*) 8*) 8*)

Yes I KNOW I am going to pay for that one Jim!  Give me at least 24 hours to
enjoy it though.  Please!



> Now if you have a magic recipe for inhibiting the spray
> of abrasive particles whenever I use mine that would be
> truly amazing.

The Impossible we do immediately...Miracles take a little longer!!

I do a LOT of grinding in my shop..98% of it on my 2HP 2" x 72" Burr King Belt
Grinder...Making Blades.

I find that placing a tray, bucket, saucer of water under the grinder, in direct
line with the jet of grit, will catch a very large portion of it..like MOST of
it.

I use a five gallon pail, because it is my slack tub (quenching container) for
cooling while grinding.

I don't use plain water (Never Drink Water...Have you seen what it does to the
inside of RADIATORS!!!)

I add a half a cup of dishwasher liquid to it (the sort that is kindest to my
hands!!)  The purpose of this is to break the surface tension and allow the dust
to sink..this stops it scumming up, rusting, contaminating the work piece and
yukking my hands when I "dunk"  I swear, it stops dust etc from bouncing off the
surface, back into the air.  Makes for a quick wash up tub, if I have to touch
something clean..Like going to take a leak!! How about that for a Teeshirt
slogan:

              Machinists always wash their hands BEFORE going to the Bathroom

I also add a half cup of Pine Sol...stops Science Experiments in their tracks!
Also prevents minor infections to your hands..makes it pong a bit sweeter too!!

Finally, I add half a cup of baking soda to my brew..stops newly ground surfaces
from instantly rusting when you dunk...for a surprisingly long time too.  I have
BAD "Rusty Hands"..every steel surface I touch will turn to rusty palmprints
before your eyes.  It used to be a major PITA, UNTIL I started using the above
mixture.  I think the constant dunking of my hands in it also helps to
neutralize the acid sweat before it can do any harm!

Steel parts come out with what seems to be a short to medium term protective
coating.  I can freshly grind a blade, quench it and chuck it under the bench
for a month or more..even in the middle of summer.  Provided I don't handle it
too much, it will remain rust free.

(As an aside to that, when I went to interview for my Apprenticeship, the
"Super" gave me a freshly made steel bolt to look at and handle.  I later
discovered this was standard hiring procedure,  The bolt was left on the desk
overnight, and if it was tool badly rusted the following morning..They didn't
hire you as an apprentice!!)

I don't get much dust from grinding on the wheels, and I try to avoid dressing
needlessly.  If a wheel is properly chosen, mounted, balanced and dressed in the
first place, and provided it is properly used..it won't need redressing wery
often.   Couple of times a year in my shop.

When  I DO fetch out the star wheel, I use the above quoted receptacle of
"water", and I cover everything in sight with DAMP towels..They catch and trap
the dust far better than dry ones do.  Spray down every exposed surface with WD
40  or something similar and then have a good wipe up after.  The oil may trap
dust on machine surfaces..but that is far better than having the DRY dust
ricochetting around and finally settling on surfaces you CAN'T reach.

cheers

teenut

From: mikegraham@sprint.ca (Mike Graham)
Newsgroups: rec.crafts.metalworking
Subject: Re: Dressing grinding wheels; Was: drill sharpening FAQ?
Date: Sat, 16 Oct 1999 22:23:42 GMT

On Sat, 16 Oct 1999 18:35:08 GMT, Robert Bastow wrote:

>Should have known the "rules" don't apply to Mike!!  ;^)

  I've been using the same single diamond point for about 10 years, so I
must be doing *something* right.  It gets used about weekly, on all of the
stones even the 8" rock on the rough grinder.

>Dwelling on the wheel will overheat and crack the diamond.

  I don't agree with this.  Since the depth of cut is set and can't be
changed, why would it overheat?  After a couple of revolutions of the wheel
the diamond should have removed all it's going to remove, and after that
it's just sittin' in the wind getting cooled down.  I'll have to try feeling
the diamond after using it.  My only worry with it is taking too deep a cut
and nicking the brass that holds the diamond in place.

>There are "jigs" and "JIGS"  Yes, with care, correct presentation angles etc.,
>you can dress, even a surface grinder wheel, "By Hand"...many systems are not
>much removed from this. The diamond being pushed by hand or lever.  It is the
>RATE of such pushing, the DEPTH of cut and the ANGLE of the diamond to
>the wheel that is likely to cause a biginner problems.
>
>But that isn't "Freehand" which is what I was originally asked about.

  Well, my 'jig' amounts to a collar on the dresser that rides along the
front edge of the toolrest.  I lay the dresser flat on the tool rest, and
move it from the left to the right in one pass.  Are you saying that I'd be
better off doing several fast passes instead of one slow one?

>For "freehand" dressing of a bench grinding wheel you can't do better than a
>star wheel dresser.

  I like the diamond because it allows me to get the face of the wheel
parallel with the toolrest which makes life simpler when I'm using it.

--
Mike Graham, mikegraham at sprint dot ca
Caledon, Ontario, Canada (just NW of Toronto).

Raiser of animals.  Weldor of metals.  Driver of off-road vehicles.
Writer of FAQs.  Keeper of the faith, and all around okay guy.

 < homepage currently off-line due to change of ISP; back soon >

From: Robert Bastow <teenut@home.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: Dressing grinding wheels; Was: drill sharpening FAQ?
Date: Sun, 17 Oct 1999 01:39:23 GMT

Mike Graham wrote:

> On Sat, 16 Oct 1999 19:54:07 -0400, Gary Coffman wrote:
>
> >The textbooks say that moving the diamond quickly will essentially
> >"thread" the wheel, which makes it softer and more aggressive
> >cutting. Moving the diamond slowly will give a harder and less
> >aggressive wheel which will produce a finer finish on the work.
>
>   It was this 'threading' effect that I was trying to avoid.  At the time I
> couldn't imagine any reason why you would want a serrated surface on a
> grinding wheel.  I suppose for roughing it might make sense, but I still
> have a hard time imagining a good reason for doing that on a finishing
> wheel.

Gary is right on the money there Mike

Think of it like the spiral toothed, roughing end mill that we discussed
earlier, Mike..though the face is "threaded" it won't produce a "thread" across
the work..unless it is guided at the same pitch as in thread grinding.

There is however less of the wheel in contact at any given moment = less heat,
"easier", deeper cutting, but faster wear!!

The opposite extreme is a wheel face that has been "dressed into submission"!!
It is SO smooth, that, while it can, with care produce a finish finer than its
grit size..it is very slow cutting and easy to "burn" the work.

"Burning" happens when the work suddenly reaches a  temperature where a spot on
the face gets into a momentary "Chain reaction"..The spot expands locally, digs
into the wheel, expands more, digs deeper..This happens in a split second and
can ruin the workpiece by leaving marks too deep to grind out.  Not only that, I
have seen jobs so buckled by the heat that they lift right off the table.

I have also seen wheels burst by the sudden expansion of the job against the
wheel..in one case a 24" diameter x 4" wide cylindrical grinder wheel!  The
operator, a highly skilled toolmaker, shakily lit a cigarette, told me he was
going to the pub for "a cup of tea" walked out and the following day got a job
as a truck driver!!

It can happen, even to an "Expert"..but is a noted "tyro's" disease, because it
is generally caused by "Too much care"  That is, in trying too hard, to get the
finish "perfect' the wheel is dressed juuust a little too smooth, and traversed
juuuust a little too slowly on that last cut!

Some materials..Stainless steel and titanium for example can be really
troublesome to finish grind because of this phenomenon.  You really do have to
have your ducks in a row on wheel choice, dressing, speeds feeds coolant....etc,
or it will turn you grey before your time!

teenut

From: Robert Bastow <"teenut"@ hotmail.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: Bearings on Buffer Question
Date: Tue, 01 Feb 2000 14:14:11 GMT

One Basis precaution when starting up a "new" or Strange" griner for the first
time..

Take the wheel off and "ring it"..it may wll be cracked.

Start the grinder WITHOUT the wheels..check for vibration, bent spindles etc.

Put on NEW wheels if you can..If this is not practical or desireable..Check the
wheel for cracks (as above)..Check it for BALANCE..wheels left staionary for a
long time will go out of balance just by dint of the dust that accumulates.
Sometimes I think that any oil that got on the wheel, during its previous life,
seems to migrate to the bottom.  Of course, if it was left standing, partially
in water or coolant (A real NO-NO..But s**t happens!!) could be badly out of
balance.  Check it also for runout.

The danger then is not just an exploded wheel..(You WILL be standing well
clear)..but also a bent spindle.

I am not trying to "teach Grannie to suck eggs" here Fitch..I know you are fully
aware of the precations to take.  My comments are aimed at the "Newbies" who
have yet to experience the exquisite delight of having a grinding wheel explode
nearby...It turns grown men PALE!!

teenut

"Fitch R. Williams" wrote:

> Robert Bastow <"teenut"@ hotmail.com> wrote:
>
> >Stand well clear when you do Fitch...5HP @ 3600 rev/min would have you as a
> >SNACK!!
>
> Trust me on this - I    u n d e r s t a n d ! <G>
>
> >Concerned.
>
> I'm concerned enough for the both of us.  I've looked at the guards and the
> welded up "gable" that is 2" away from the wheel and decided it needs many
> modifications before it gets used.  I am holding off on the mods until I
> find out if it runs.  So it will get started with me standing far away and
> we shall see if it runs.  If it does, it will be modified to be safe before
> I use it.
>
> I've had a small piece of steel tubing - part of a model I was making
> (maybe 1/8" in diameter) jammed through my hand by a 1/2 hp grinder in my
> youth, I have "plenty" of respect for this one!
>
> I also wish it was a 1725 rpm grinder.  The wheels are maybe 1-1/2" thick.
>
> Fitch
> In So. Cal.

From: Robert Bastow <"teenut"@ hotmail.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: Bearings on Buffer Question
Date: Tue, 01 Feb 2000 19:08:50 GMT

Especially if that "something" is one or more of your body parts!!

8^(

teenut

Jim Kovar wrote:
>
> > Take the wheel off and "ring it"..it may wll be cracked.
> >
> > Start the grinder WITHOUT the wheels..check for vibration, bent spindles
> etc.
>
>             One other thing I'm sure you know,  (but it's important)  is to
> check the clearance between the tool rest and the wheel.
>   Gets scary real fast when something gets pulled down into the clearance
> space on a big grinder. They DON'T stall easily.
>
>            Take care :)
>                                         Jim Kovar
>                                         Iron Mountain, Mi

From: Robert Bastow <"teenut"@ hotmail.com>
Newsgroups: rec.crafts.metalworking
Subject: Re: Dressing a Grinding wheel
Date: Sun, 14 May 2000 03:31:35 GMT

If you learn to use it properly the star type shouldn't leave Divots in your
wheel..sounds like you are using too much pressure.  Use light pressure and try
to hold the wheels at a slight angle to the wheel face so that they spin freely
at wheel speed.

Done properly the star wheel will leave a vastly superior grinding surface than
any stick or diamond.  It works by crushing the bond and thus allowing grit to
be pulled off..leaving fresh, sharp, undamaged grit and a fresh "open" bonded
face that will cut more freely, cooler and with less loading.

Sticks etc work by cutting the individual grits..leaving a mish mash of damaged
cutting grits behind.  the wheel may "Look" smoother..but it won't cut as
freely, will heat up faster and will load and glaze far faster.

I have never actually done scientific tests..but in my experience a star dressed
wheel face will outlast a stick dressed one..between dressings..by a factor of
at least ten!!!

teenut  Who has dressed a few!!

John Jacobs wrote:

> What do you think is better. A star type wheel dresser or a dressing
> stick? The star type seems to leave small divots in my wheel. Thanks in
> advance.
> John