As

Australopithecus scobis

08/12/2004 6:34 PM

grinding wheels--when do you replace?

Greetings,

I've had my first grinder for a few months now. (Ugly grey wheels used to
chew up metal, not for sharpening...)

I'm wondering how small you let the wheels get before you replace them.
Five inches? Down to the label?

I'm asking here instead of the metalworking group, because I think
metalworkers would have different tolerances and applications than woodies
do.

--
"Keep your ass behind you"
vladimir a t mad {dot} scientist {dot} com


This topic has 12 replies

rr

"robdingnagian1"

in reply to Australopithecus scobis on 08/12/2004 6:34 PM

08/12/2004 5:25 PM

What size is the grinder?


Australopithecus scobis wrote:
> Greetings,
>
> I've had my first grinder for a few months now. (Ugly grey wheels
used to
> chew up metal, not for sharpening...)
>
> I'm wondering how small you let the wheels get before you replace
them.
> Five inches? Down to the label?
>
> I'm asking here instead of the metalworking group, because I think
> metalworkers would have different tolerances and applications than
woodies
> do.
>
> --
> "Keep your ass behind you"
> vladimir a t mad {dot} scientist {dot} com

BG

Bob G.

in reply to Australopithecus scobis on 08/12/2004 6:34 PM

09/12/2004 12:28 PM


>
>What does your manual say?? I was raised in my grinder youth to keep
>the tool rest 1/8" away from the wheel. As the wheel wore down, you
>adjust the rest to within an 1/8". When you can no longer do that, the
>wheel needs to be replaced.


I am in my 60's....and your method is exactly the procedure that my
Dad told his "young" son many many years ago.... He was primarly a
metal worked BUT I have followed his advice and never ran into
problems....

AND I have to THANK YOU

for bringing back memories of my Dad today... I Miss the old Sob
..."Sweet old Bob" ... thats how my Mom used to refer to him ....
Unfortunately I think my wife uses the more common meaning when she is
refering to me... especially this time of year when I am overly
protective of the checkbook...

Bob Griffiths


Ma

Mark and Kim Smith

in reply to Australopithecus scobis on 08/12/2004 6:34 PM

09/12/2004 5:30 AM

Australopithecus scobis wrote:

>Greetings,
>
>I've had my first grinder for a few months now. (Ugly grey wheels used to
>chew up metal, not for sharpening...)
>
>I'm wondering how small you let the wheels get before you replace them.
>Five inches? Down to the label?
>
>I'm asking here instead of the metalworking group, because I think
>metalworkers would have different tolerances and applications than woodies
>do.
>
>
>

What does your manual say?? I was raised in my grinder youth to keep
the tool rest 1/8" away from the wheel. As the wheel wore down, you
adjust the rest to within an 1/8". When you can no longer do that, the
wheel needs to be replaced. Also, if your wheel clogs from aluminum,
brass or whatever, best replace it before it shrapnel's on you. It
helps to have a wheel dresser.

Whether you are a woodworker or a metalworker, that wheel will spin the
same speed. Spending it's life trying to throw it's weight away from
center. Taking it down to the "label" the wheel won't care who you are
and will throw pieces at you when it fractures. ( Gee! Do you think
I've watched too many safety video's that show projectiles piercing
peoples faces and eyes and such?? Yup! At least once a year!!)

Reminds me of the Maximum Exposure video where a guy ends up with half
of a 10" grinding wheel in his skull. He has it removed and they show
him grinding away on a new wheel, big ol' bandage on his head. On the
video, he says that he doesn't believe in personal protection and won't
ever wear that stuff! I think he could use a Darwin award ( or he'll
win one he keeps going the direction he's taking!)

Jm

"J"

in reply to Australopithecus scobis on 08/12/2004 6:34 PM

09/12/2004 11:59 AM

"Mark and Kim Smith" <[email protected]> wrote in message

> Whether you are a woodworker or a metalworker, that wheel will spin the
> same speed.

Well, not really. RPM may be the same, but the speed at the edge of the
wheel will be different. If a 6 inch diameter wheel is spinning at 1000
times a minute, the edge of it will be moving at about 1500 feet per minute.
If the wheel wears down to 4 inches then the edge moves at 1000 feet per
minute.

-j

Ma

Mark and Kim Smith

in reply to Australopithecus scobis on 08/12/2004 6:34 PM

09/12/2004 4:06 PM

Bob G. wrote:

>>What does your manual say?? I was raised in my grinder youth to keep
>>the tool rest 1/8" away from the wheel. As the wheel wore down, you
>>adjust the rest to within an 1/8". When you can no longer do that, the
>>wheel needs to be replaced.
>>
>>
>
>
>I am in my 60's....and your method is exactly the procedure that my
>Dad told his "young" son many many years ago.... He was primarly a
>metal worked BUT I have followed his advice and never ran into
>problems....
>
>AND I have to THANK YOU
>
> for bringing back memories of my Dad today... I Miss the old Sob
>..."Sweet old Bob" ... thats how my Mom used to refer to him ....
>Unfortunately I think my wife uses the more common meaning when she is
>refering to me... especially this time of year when I am overly
>protective of the checkbook...
>
>Bob Griffiths
>
>
>
>
>

Glad I could bring you some good memories! Happy Holidays!!

Ma

Mark and Kim Smith

in reply to Australopithecus scobis on 08/12/2004 6:34 PM

09/12/2004 4:17 PM

J wrote:

>"Mark and Kim Smith" <[email protected]> wrote in message
>
>
>
>>Whether you are a woodworker or a metalworker, that wheel will spin the
>>same speed.
>>
>>
>
>Well, not really. RPM may be the same, but the speed at the edge of the
>wheel will be different. If a 6 inch diameter wheel is spinning at 1000
>times a minute, the edge of it will be moving at about 1500 feet per minute.
>If the wheel wears down to 4 inches then the edge moves at 1000 feet per
>minute.
>
>-j
>
>
>
>

Reread my sentence. If the edge of a 6" wheel is turning at 1500' per
minute, it is turning 1500' per minute whether you are a woodworker or
whether you are a metal worker ( or an office worker.) If the wheel
wears down to 4" and the edge turns at 1000' per minute, then the edge
of a woodworkers wheel turns at 1000' per minute and the edge of a
metalworkers wheel turns at 1000' per minute. Whether you are a
woodworker or a metalworker, that wheel will spin the same speed ( all
grinders being equal.) Point to the OP was that it doesn't matter
whether you are a metalworker or a woodworker, it is a grinder and
manufacturers have specifications on how to operate their product.

Jm

"J"

in reply to Australopithecus scobis on 08/12/2004 6:34 PM

09/12/2004 1:20 PM


"Mark and Kim Smith" <[email protected]> wrote in message
> Reread my sentence. If the edge of a 6" wheel is turning at 1500' per
> minute, it is turning 1500' per minute whether you are a woodworker or
> whether you are a metal worker ( or an office worker.) If the wheel
> wears down to 4" and the edge turns at 1000' per minute, then the edge
> of a woodworkers wheel turns at 1000' per minute and the edge of a
> metalworkers wheel turns at 1000' per minute. Whether you are a
> woodworker or a metalworker, that wheel will spin the same speed ( all
> grinders being equal.)

Oh.... Nevermind.

As

Australopithecus scobis

in reply to Australopithecus scobis on 08/12/2004 6:34 PM

08/12/2004 9:39 PM

On Wed, 08 Dec 2004 17:25:26 -0800, robdingnagian1 wrote:

> What size is the grinder?

6" Delta

As

Australopithecus scobis

in reply to Australopithecus scobis on 08/12/2004 6:34 PM

08/12/2004 9:42 PM

On Wed, 08 Dec 2004 19:53:39 -0600, The Davenport's wrote:

> 6.4" on an 8" wheel. And 5.1" to 4.8" for a 6" wheel.
>
> I also keep one handy that's down to about 50% or so for fine grinding

Thanks much. That's the info I was looking for.

As

Australopithecus scobis

in reply to Australopithecus scobis on 08/12/2004 6:34 PM

09/12/2004 8:36 AM

On Thu, 09 Dec 2004 05:30:44 -0500, Mark and Kim Smith wrote:

> What does your manual say??

Oh. You see, I used to write tech doc for a living. I never read the
steenkin' manual. Your point about the tool rest is kinda obvious. Duh.
(Finally, a use for the "tool rest" that is otherwise useless!) Thanks.

(The reduction in size is mostly due to my enthusiastic use of a star
dresser. Won't get a diamond one until I have a proper rest and some white
wheels.)

--
"Keep your ass behind you"
vladimir a t mad {dot} scientist {dot} com

Br

Ba r r y

in reply to Australopithecus scobis on 08/12/2004 6:34 PM

09/12/2004 1:29 PM

On Wed, 08 Dec 2004 18:34:29 -0600, Australopithecus scobis
<[email protected]> wrote:


>I'm wondering how small you let the wheels get before you replace them.
>Five inches? Down to the label?

Some people like as small wheels as possible, as it grinds a deeper
hollow in a hollow grind.

Barry

TD

"The Davenport's"

in reply to Australopithecus scobis on 08/12/2004 6:34 PM

08/12/2004 7:53 PM

> Greetings,
>
> I've had my first grinder for a few months now. (Ugly grey wheels used to
> chew up metal, not for sharpening...)
>
> I'm wondering how small you let the wheels get before you replace them.
> Five inches? Down to the label?
>
> I'm asking here instead of the metalworking group, because I think
> metalworkers would have different tolerances and applications than woodies
> do.
>

Just as a rule of thumb, I use 15-20% reduction before replacing a white
wheel used for sharpening. That means running it down to roughly 6.8" to
6.4" on an 8" wheel. And 5.1" to 4.8" for a 6" wheel.

I also keep one handy that's down to about 50% or so for fine grinding
something that I TRUELY don't want to risk burning. The surface speed of
these wheels will be low enough that it'll take a long time to sharpen a
dull tool without loading up, but for the almost honing effect you get from
the small wheels, it can't be beat.

Luck

Mike


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