"Ignoramus3644" wrote in message
...
Found a 2" piece of solid round barstock. I will drill a 7/8" hole for
the motor shaft, and another hole for the wheel holding bolt. Not sure
what diameter to use. I have some big taps. Is there a tap that
requires a 7/8" hole? I bought a 7/8" drill. I have a 1" tap, but it
prolly needs a special diameter drill bit which I do not have.

i
--

You're unlikely to be pleased with the hole you'll drill due to runout. The
best way to go about this is to drill the hole undersized, then bore it,
providing a snug slip fit on the motor shaft. Barring that scenario, the
next best thing to do is drill two sets of three holes @ 120
degrees---spaced one set at each end of the arbor, so you can adjust the
runout once it's assembled on the motor shaft.

If you haven't made anything like this before, you should give it
considerable thought before striking out on the project. It is important
for the arbor you make to run dead true, and be the proper size for the
wheel you'll use. It should also have flanges of the proper size, which
support the wheel only on the outside edges. An improperly made arbor can
cost you your life. Be careful, and feel free to ask for guidance if you
have any questions. Any number of us can provide enough information to
keep you safe.

Harold

In article ,
Harold and Susan Vordos wrote:

"Ignoramus3644" wrote in message
. ..
Found a 2" piece of solid round barstock. I will drill a 7/8" hole for
the motor shaft, and another hole for the wheel holding bolt. Not sure
what diameter to use. I have some big taps. Is there a tap that
requires a 7/8" hole? I bought a 7/8" drill. I have a 1" tap, but it
prolly needs a special diameter drill bit which I do not have.

[ ... ]

It should also have flanges of the proper size, which
support the wheel only on the outside edges. An improperly made arbor can
cost you your life.

I agree with all that Harold has said, but in particular, I
suspect that I should add a little more detail to the bit about the
flanges. what he means by the "outside edges" is that the flanges
should be dished, so they only apply pressure to the wheel at a diameter
just a bit within the maximum diameter of the blotter-paper labels on
the wheels. And you should *never* mount a wheel without those blotter
paper labels -- they are needed to prevent crushing the stone and
starting it to fracture. Once it starts to crack, it *will* explode at
speed. The bigger the wheel, and the faster it is turning, the more
energy is stored in it, with the capability to do serious damage,
possibly fatal.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"Harold and Susan Vordos" wrote in message
...

"Ignoramus3644" wrote in message
...
Found a 2" piece of solid round barstock. I will drill a 7/8" hole for
the motor shaft, and another hole for the wheel holding bolt. Not sure
what diameter to use. I have some big taps. Is there a tap that
requires a 7/8" hole? I bought a 7/8" drill. I have a 1" tap, but it
prolly needs a special diameter drill bit which I do not have.

i
--

You're unlikely to be pleased with the hole you'll drill due to runout.
The
best way to go about this is to drill the hole undersized, then bore it,
providing a snug slip fit on the motor shaft. Barring that scenario, the
next best thing to do is drill two sets of three holes @ 120
degrees---spaced one set at each end of the arbor, so you can adjust the
runout once it's assembled on the motor shaft.

These holes would be tapped and set screws installed. Sorry to have left
that part out.

H

On Fri, 12 Aug 2005 00:37:27 GMT, Ignoramus3644
wrote:

Found a 2" piece of solid round barstock. I will drill a 7/8" hole for
the motor shaft, and another hole for the wheel holding bolt. Not sure
what diameter to use. I have some big taps. Is there a tap that
requires a 7/8" hole? I bought a 7/8" drill. I have a 1" tap, but it
prolly needs a special diameter drill bit which I do not have.

i


Sigh..Ive about 800 lbs of shaft arbors, from about 1/2" to 3" OD.

What size do you want? I still have those electical boxes if you
need one

Gunner

The two highest achievements of the human mind are the twin concepts of "loyalty" and "duty."
Whenever these twin concepts fall into disrepute -- get out of there fast! You may possibly
save yourself, but it is too late to save that society. It is doomed. " Lazarus Long

Ignoramus3644 wrote:
Found a 2" piece of solid round barstock. I will drill a 7/8" hole for
the motor shaft, and another hole for the wheel holding bolt. Not sure
what diameter to use. I have some big taps. Is there a tap that
requires a 7/8" hole? I bought a 7/8" drill. I have a 1" tap, but it
prolly needs a special diameter drill bit which I do not have.

i



I don't know how large a wheel you are going to mount on that motor, but
if it's small enough to be safely held by a 1/2" bolt, you could
consider turning the motor shaft down to 1/2" diameter far enough back
to put one of these cheapies on:

http://www.harborfreight.com/cpi/cta...emnumber=46623

I'm not proud to say this, but more than once in my short life I've
successfully "turned down" the diameter of a motor shaft by carefull
application of a flat file while the motor was spinning, combined with
frequent stops to check the progress with a mike.

Perhaps I was lucky and never encountered a shaft with hard spots in it
which could have screwed things up. The shafts always came out with less
runout than the crummy die cast V-belt pullies I was making them fit,
and you've got to true up a grinding wheel after it's mounted anyway. G.

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

Ignoramus19325 wrote:

On Fri, 12 Aug 2005 10:57:14 -0400, Jeff Wisnia wrote:

Ignoramus3644 wrote:

Found a 2" piece of solid round barstock. I will drill a 7/8" hole for
the motor shaft, and another hole for the wheel holding bolt. Not sure
what diameter to use. I have some big taps. Is there a tap that
requires a 7/8" hole? I bought a 7/8" drill. I have a 1" tap, but it
prolly needs a special diameter drill bit which I do not have.

i



I don't know how large a wheel you are going to mount on that motor, but
if it's small enough to be safely held by a 1/2" bolt, you could
consider turning the motor shaft down to 1/2" diameter far enough back
to put one of these cheapies on:

http://www.harborfreight.com/cpi/cta...emnumber=46623

I'm not proud to say this, but more than once in my short life I've
successfully "turned down" the diameter of a motor shaft by carefull
application of a flat file while the motor was spinning, combined with
frequent stops to check the progress with a mike.

Perhaps I was lucky and never encountered a shaft with hard spots in it
which could have screwed things up. The shafts always came out with less
runout than the crummy die cast V-belt pullies I was making them fit,
and you've got to true up a grinding wheel after it's mounted anyway. G.


Thanks Jeff. I became a little fearful about this project. If I went
ahead with it, it would be for large wheels, since I already have a
small 1/6 HP grinder. I would not want to rely on a $3 Harbor Freight
adapter. As someone pointed out, I or loved ones could get killed
quite easily.

i


Yeah, I agree. Any you certainly would want some heavy guards around a
large wheel too. Might be better to keep your eyes open for a used
"tailor made" larger grinder and find something else to hone your
machining skills on.

Have a great weekend,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

On Fri, 12 Aug 2005 11:43:42 -0400, Jeff Wisnia
wrote:

Ignoramus19325 wrote:

On Fri, 12 Aug 2005 10:57:14 -0400, Jeff Wisnia wrote:

Ignoramus3644 wrote:

Found a 2" piece of solid round barstock. I will drill a 7/8" hole for
the motor shaft, and another hole for the wheel holding bolt. Not sure
what diameter to use. I have some big taps. Is there a tap that
requires a 7/8" hole? I bought a 7/8" drill. I have a 1" tap, but it
prolly needs a special diameter drill bit which I do not have.

i



I don't know how large a wheel you are going to mount on that motor, but
if it's small enough to be safely held by a 1/2" bolt, you could
consider turning the motor shaft down to 1/2" diameter far enough back
to put one of these cheapies on:

http://www.harborfreight.com/cpi/cta...emnumber=46623

I'm not proud to say this, but more than once in my short life I've
successfully "turned down" the diameter of a motor shaft by carefull
application of a flat file while the motor was spinning, combined with
frequent stops to check the progress with a mike.

Perhaps I was lucky and never encountered a shaft with hard spots in it
which could have screwed things up. The shafts always came out with less
runout than the crummy die cast V-belt pullies I was making them fit,
and you've got to true up a grinding wheel after it's mounted anyway. G.


Thanks Jeff. I became a little fearful about this project. If I went
ahead with it, it would be for large wheels, since I already have a
small 1/6 HP grinder. I would not want to rely on a $3 Harbor Freight
adapter. As someone pointed out, I or loved ones could get killed
quite easily.

i


Yeah, I agree. Any you certainly would want some heavy guards around a
large wheel too. Might be better to keep your eyes open for a used
"tailor made" larger grinder and find something else to hone your
machining skills on.

Have a great weekend,

Jeff

That's why I suggested a belt sander (I think in another thread).
Lots less risk, faster removal rate. Of course, it's a little to a lot
more complex depending on how fancy you get. There are lots of plans
or at least photos on the web. I'm considering building one myself,
although probably not as fancy as the Beaumont one.

Pete Keillor