If you recall, I had a struggle with a Ryobi bench grinder given to me
by a well-meaning relative. I first reported the saga in the thread
"Vibrating grinder returns" (21 April 2007). The then plan was to
machine new end washers to stabilize the stone wheels on the 5/8" arbor
shafts.

The Clausing 5914 is now up to the task, and so it was done. Actually,
I retained the pressed steel end washers, but used the lathe to face off
the center where the nut clamp on the washer. I also machined a pair of
1" OD, 5/8' ID by 1.35" long sleeves of mild steel, to adapt the Norton
wheels (1" diameter hole) to the 5/8" diameter arbor shafts.

So I put it all together today. The grinder still vibrates badly, with
wheels both wobbling side-to-side! But now the reason is obvious; it
was not obvious before (because the pressed steel washers were not
accurate). The two nuts that hold wheels onto the arbors are crooked,
very crooked. The thread axis is not perpendicular to the faces of the
nuts, so when one tightens down, the pressure is all on one side of the
washer, and so the wheel sways. The deviation is quite large, and
easily visible. The left-hand thread nut even looks wrong: the threaded
hole is noticeably eccentric in the hex nut outline.

What were they thinking? They have rendered the whole affair almost
useless by provision of cheaply made nuts. This has to have saved all
of ten cents.

Naturally, the nuts are actually metric, and appear to be M16-2.0, which
looks like 5/8-11, but is not. The 5914 lathe does not cut metric
threads. Closest it gets is 12 tpi, versus 25.4/2= 12.7 tpi. So I
can't just make a set of nuts, my first thought.

My second thought was to re-face the provided nuts. That didn't work
either, because the screwthread axis is not parallel to the hex facets
of the nuts. So, I gave up.

I will call Ryobi, in the hope that they now have better-made nuts. But
I'm close to junking this POS. It's been far too educational.

I was looking at the Delta 8" bench grinder. Amazon offers this unit.
Interestingly, there was exactly one customer comment, and that one
customer complained of excessive vibration caused by wobbling wheels.
Wonder if Delta buys its nuts the same place.

Joe Gwinn

Naturally, the nuts are actually metric, and appear to be M16-2.0, which
looks like 5/8-11, but is not. The 5914 lathe does not cut metric
threads. Closest it gets is 12 tpi, versus 25.4/2= 12.7 tpi. So I
can't just make a set of nuts, my first thought.

My second thought was to re-face the provided nuts. That didn't work
either, because the screwthread axis is not parallel to the hex facets
of the nuts. So, I gave up.

I will call Ryobi, in the hope that they now have better-made nuts. But
I'm close to junking this POS. It's been far too educational.


Joe Gwinn


you may consider machining the nuts in place - spin the grinder up to speed
and hold a cutting tool against the exposed face of the nut


** Posted from http://www.teranews.com **

On 2008-04-14, Joseph Gwinn wrote:
If you recall, I had a struggle with a Ryobi bench grinder given to me
by a well-meaning relative. I first reported the saga in the thread
"Vibrating grinder returns" (21 April 2007). The then plan was to
machine new end washers to stabilize the stone wheels on the 5/8" arbor
shafts.

[ ... ]

accurate). The two nuts that hold wheels onto the arbors are crooked,
very crooked. The thread axis is not perpendicular to the faces of the
nuts, so when one tightens down, the pressure is all on one side of the
washer, and so the wheel sways. The deviation is quite large, and
easily visible. The left-hand thread nut even looks wrong: the threaded
hole is noticeably eccentric in the hex nut outline.

[ ... ]

Naturally, the nuts are actually metric, and appear to be M16-2.0, which
looks like 5/8-11, but is not. The 5914 lathe does not cut metric
threads. Closest it gets is 12 tpi, versus 25.4/2= 12.7 tpi. So I
can't just make a set of nuts, my first thought.

My second thought was to re-face the provided nuts. That didn't work
either, because the screwthread axis is not parallel to the hex facets
of the nuts. So, I gave up.

Well ... probably the nuts on the left-hand side of the grinder
are left-hand thread -- but at least for the right-hand nut -- chuck an
appropriate screw (you can get the M16x2.0 locally can't you), in the
lathe with just enough sticking out the end and screw the nut onto it.
Then face the nut in that position. If both sides use a right-hand nut
you can do both sides easily. Otherwise, go to MSC (or some similar
supplier) and look for LH bolts in the right thread. Or -- just look
for good quality nuts in both hands.

I could probably make you a stud for facing the left-hand nut
which you (presumably) already have -- using the Compact-5/CNC Emco
Maier lathe. But I will have to trust measuring over wires, because I
don't have a left hand thread sample to work from.

Enjoy,
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 ---

you may consider machining the nuts in place - spin the grinder up to
speed and hold a cutting tool against the exposed face of the nut


a bit more on what I posted above - if you have a die grinder or dremel tool
and can hold it still (perhaps with a clamp, or maybe by holding it in the
lathe's tool rest) you can grind away at the outside face of the nut with
the grinder running, it will take less time than ordering a replacement or
making one or going to the store to buy one. You could also make a sleeve
that fits the shaft accurately and is thick ehough that it won't wobble when
the nut pushes on it off center


** Posted from http://www.teranews.com **

On 14 Apr 2008 05:10:34 GMT, "DoN. Nichols"
wrote:



I could probably make you a stud for facing the left-hand nut
which you (presumably) already have -- using the Compact-5/CNC Emco
Maier lathe. But I will have to trust measuring over wires, because I
don't have a left hand thread sample to work from.

Threads on import nuts and bolts I've seen bear little resemblance to
any specification, so measuring over wires would be futile unless you
had 3-wire measurements of the shaft on his grinder.

Better to have him send you the nut so you can make a stud to fit --
and then you may as well face the nut for him since you'd already
have the stud in your lathe. G

I would indeed junk the grinder.

There is too much at stake with the fast spinning wheel.

i

In article ,
"DoN. Nichols" wrote:

On 2008-04-14, Joseph Gwinn wrote:
If you recall, I had a struggle with a Ryobi bench grinder given to me
by a well-meaning relative. I first reported the saga in the thread
"Vibrating grinder returns" (21 April 2007). The then plan was to
machine new end washers to stabilize the stone wheels on the 5/8" arbor
shafts.

[ ... ]

accurate). The two nuts that hold wheels onto the arbors are crooked,
very crooked. The thread axis is not perpendicular to the faces of the
nuts, so when one tightens down, the pressure is all on one side of the
washer, and so the wheel sways. The deviation is quite large, and
easily visible. The left-hand thread nut even looks wrong: the threaded
hole is noticeably eccentric in the hex nut outline.

[ ... ]

Naturally, the nuts are actually metric, and appear to be M16-2.0, which
looks like 5/8-11, but is not. The 5914 lathe does not cut metric
threads. Closest it gets is 12 tpi, versus 25.4/2= 12.7 tpi. So I
can't just make a set of nuts, my first thought.

My second thought was to re-face the provided nuts. That didn't work
either, because the screwthread axis is not parallel to the hex facets
of the nuts. So, I gave up.

Well ... probably the nuts on the left-hand side of the grinder
are left-hand thread -- but at least for the right-hand nut -- chuck an
appropriate screw (you can get the M16x2.0 locally can't you), in the
lathe with just enough sticking out the end and screw the nut onto it.
Then face the nut in that position. If both sides use a right-hand nut
you can do both sides easily. Otherwise, go to MSC (or some similar
supplier) and look for LH bolts in the right thread. Or -- just look
for good quality nuts in both hands.

The left arbor has a left-hand thread, the right arbor has a right-hand
thread. Both are M16x2. (There is no rotor lock, so it can be hard to
tighten and loosen the nuts.)

I don't know how common left-hand metric bolts are round these parts.

MSC and Grainger have none. Nor do I really want to buy 100 of these
nuts. At $20/100 times two, or $40, it's 2/3 what the grinder cost.


I could probably make you a stud for facing the left-hand nut
which you (presumably) already have -- using the Compact-5/CNC Emco
Maier lathe. But I will have to trust measuring over wires, because I
don't have a left hand thread sample to work from.

I'm not sure that the threaded stud to hold the nut to be faced will
work, as both faces are crooked, so the nut will tilt to one side when
tightened down to allow facing the free face. I think that the only
solution is new nuts. I could make these nuts if I bought a set of
taps, but even that is going to cost a major fraction of the cost of the
grinder.

I'm going to call Roybi first. Maybe they have resolved their supply
problem. Or gotten lucky.

Hmm. I wonder what thread Jet grinders use?

Joe Gwinn

In article ,
Don Foreman wrote:

On 14 Apr 2008 05:10:34 GMT, "DoN. Nichols"
wrote:



I could probably make you a stud for facing the left-hand nut
which you (presumably) already have -- using the Compact-5/CNC Emco
Maier lathe. But I will have to trust measuring over wires, because I
don't have a left hand thread sample to work from.

Threads on import nuts and bolts I've seen bear little resemblance to
any specification, so measuring over wires would be futile unless you
had 3-wire measurements of the shaft on his grinder.

Better to have him send you the nut so you can make a stud to fit --
and then you may as well face the nut for him since you'd already
have the stud in your lathe. G

Or even better, make the correct nut. But I think it's a loose M16x2.
great precision is not required. Only perpendicularity. In any event,
if it comes to that, I can measure the arbor thread over three wires.

Joe Gwinn

In article ,
Ronald Thompson wrote:

Don Foreman wrote:
On 14 Apr 2008 05:10:34 GMT, "DoN. Nichols"
wrote:


I could probably make you a stud for facing the left-hand nut
which you (presumably) already have -- using the Compact-5/CNC Emco
Maier lathe. But I will have to trust measuring over wires, because I
don't have a left hand thread sample to work from.

Threads on import nuts and bolts I've seen bear little resemblance to
any specification, so measuring over wires would be futile unless you
had 3-wire measurements of the shaft on his grinder.

Better to have him send you the nut so you can make a stud to fit --
and then you may as well face the nut for him since you'd already
have the stud in your lathe. G

If the nut is drilled off center, will facing it do much good? It may
make the wheel straighter, but the nut will still be off center.

Compared to the wheel, the mass of the nut is trivial, and so some
eccentricity is harmless in the nut. The issue is the degree of
parallelism between thread axis and the hex flats, as it's to the flats
that one clamps.

It appears that the thread was tapped at an angle to the body of the nut.


The first thing I would do is run the grinder without wheels and see if
it is smooth. If not, junk it unless you want to tear it apart. Next,
check the shafts for trueness with a dial indicator.
Then I'd add pieces one at a time to see what is vibrating.

The grinder runs smoothly without wheels. The shaft runs true according
to the dial indicator.

Joe Gwinn

In article ,
"Bill Noble" wrote:



you may consider machining the nuts in place - spin the grinder up to
speed and hold a cutting tool against the exposed face of the nut


a bit more on what I posted above - if you have a die grinder or dremel tool
and can hold it still (perhaps with a clamp, or maybe by holding it in the
lathe's tool rest) you can grind away at the outside face of the nut with
the grinder running, it will take less time than ordering a replacement or
making one or going to the store to buy one. You could also make a sleeve
that fits the shaft accurately and is thick ehough that it won't wobble when
the nut pushes on it off center

A lathe tool bit wouldn't work, as the motor is too fast and too weak to
be a lathe motor.

The die grinder could work.

The hard part is holding the nut in place without tilting it, even
though the nut's faces are tilted with respect to the arbor axis. I'm
thinking a strong spring on the arbor will be strong enough for the die
grinder.

Joe Gwinn

On Mon, 14 Apr 2008 06:37:19 -0400, Ronald Thompson
wrote:

Don Foreman wrote:
On 14 Apr 2008 05:10:34 GMT, "DoN. Nichols"
wrote:


I could probably make you a stud for facing the left-hand nut
which you (presumably) already have -- using the Compact-5/CNC Emco
Maier lathe. But I will have to trust measuring over wires, because I
don't have a left hand thread sample to work from.

Threads on import nuts and bolts I've seen bear little resemblance to
any specification, so measuring over wires would be futile unless you
had 3-wire measurements of the shaft on his grinder.

Better to have him send you the nut so you can make a stud to fit --
and then you may as well face the nut for him since you'd already
have the stud in your lathe. G
If the nut is drilled off center, will facing it do much good? It may
make the wheel straighter, but the nut will still be off center.

The first thing I would do is run the grinder without wheels and see if
it is smooth. If not, junk it unless you want to tear it apart. Next,
check the shafts for trueness with a dial indicator.
Then I'd add pieces one at a time to see what is vibrating.

I'd be suspicious that it was dropped and the shaft bent.
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On Mon, 14 Apr 2008 09:00:29 -0400, Joseph Gwinn
wrote:



I don't know how common left-hand metric bolts are round these parts.

MSC and Grainger have none. Nor do I really want to buy 100 of these
nuts. At $20/100 times two, or $40, it's 2/3 what the grinder cost.

McMaster:

93695A210
Metric Class 8 Left-Hand Thread Hex Nut Zinc-Pltd, M16 Size, 2mm
Pitch, 24mm W, 13mm H
In stock at $11.20 per Pack
This product is sold in Packs of 20

Or make some spherical washers.
http://www.nolansupply.com/small_images/65332001.jpg

--
Ned Simmons

On Mon, 14 Apr 2008 09:41:18 -0400, Ned Simmons
wrote:

On Mon, 14 Apr 2008 09:00:29 -0400, Joseph Gwinn
wrote:



I don't know how common left-hand metric bolts are round these parts.

MSC and Grainger have none. Nor do I really want to buy 100 of these
nuts. At $20/100 times two, or $40, it's 2/3 what the grinder cost.

McMaster:

93695A210
Metric Class 8 Left-Hand Thread Hex Nut Zinc-Pltd, M16 Size, 2mm
Pitch, 24mm W, 13mm H
In stock at $11.20 per Pack
This product is sold in Packs of 20

or buy a single in stainless steel for $2.74


Or make some spherical washers.
http://www.nolansupply.com/small_images/65332001.jpg
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

In article ,
Ned Simmons wrote:

On Mon, 14 Apr 2008 09:00:29 -0400, Joseph Gwinn
wrote:



I don't know how common left-hand metric bolts are round these parts.

MSC and Grainger have none. Nor do I really want to buy 100 of these
nuts. At $20/100 times two, or $40, it's 2/3 what the grinder cost.

McMaster:

93695A210
Metric Class 8 Left-Hand Thread Hex Nut Zinc-Pltd, M16 Size, 2mm
Pitch, 24mm W, 13mm H
In stock at $11.20 per Pack
This product is sold in Packs of 20

I found this today as well. They also have a stainless steel nut for a
few dollars, sold in quantity 1.


Or make some spherical washers.
http://www.nolansupply.com/small_images/65332001.jpg

I already have some spherical washers, but the stackup is too thick -
there isn't enough arbor for this to fit.

Joe Gwinn

On 2008-04-14, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

Well ... probably the nuts on the left-hand side of the grinder
are left-hand thread -- but at least for the right-hand nut -- chuck an

[ ... ]

The left arbor has a left-hand thread, the right arbor has a right-hand
thread. Both are M16x2. (There is no rotor lock, so it can be hard to
tighten and loosen the nuts.)

That is common with all bench grinders that I have used.

I don't know how common left-hand metric bolts are round these parts.

:-)

MSC and Grainger have none. Nor do I really want to buy 100 of these
nuts. At $20/100 times two, or $40, it's 2/3 what the grinder cost.

Understood.

I could probably make you a stud for facing the left-hand nut
which you (presumably) already have -- using the Compact-5/CNC Emco
Maier lathe. But I will have to trust measuring over wires, because I
don't have a left hand thread sample to work from.

I'm not sure that the threaded stud to hold the nut to be faced will
work, as both faces are crooked, so the nut will tilt to one side when
tightened down to allow facing the free face.

How loose is the nut on the arbor?

I think that the only
solution is new nuts. I could make these nuts if I bought a set of
taps, but even that is going to cost a major fraction of the cost of the
grinder.

:-)

I'm going to call Roybi first. Maybe they have resolved their supply
problem. Or gotten lucky.

Hmm. I wonder what thread Jet grinders use?

A good question. I have an 8" Jet grinder -- and it has been an
excellent one so far. I guess that I could try measuring the thread on
the right-hand end with a thread checker or a thread pitch gauge. Even
if it is the same thread size and pitch, I don't know how different the
actual fit might be. :-)

Enjoy,
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 ---

In article ,
Spehro Pefhany wrote:

On Mon, 14 Apr 2008 06:37:19 -0400, Ronald Thompson
wrote:

Don Foreman wrote:
On 14 Apr 2008 05:10:34 GMT, "DoN. Nichols"
wrote:


I could probably make you a stud for facing the left-hand nut
which you (presumably) already have -- using the Compact-5/CNC Emco
Maier lathe. But I will have to trust measuring over wires, because I
don't have a left hand thread sample to work from.

Threads on import nuts and bolts I've seen bear little resemblance to
any specification, so measuring over wires would be futile unless you
had 3-wire measurements of the shaft on his grinder.

Better to have him send you the nut so you can make a stud to fit --
and then you may as well face the nut for him since you'd already
have the stud in your lathe. G
If the nut is drilled off center, will facing it do much good? It may
make the wheel straighter, but the nut will still be off center.

The first thing I would do is run the grinder without wheels and see if
it is smooth. If not, junk it unless you want to tear it apart. Next,
check the shafts for trueness with a dial indicator.
Then I'd add pieces one at a time to see what is vibrating.

I'd be suspicious that it was dropped and the shaft bent.

This was a common suspicion, but it turned out that the arbors are
straight, as measured with a dial indicator.

Joe Gwinn

In article ,
"DoN. Nichols" wrote:

On 2008-04-14, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

Well ... probably the nuts on the left-hand side of the grinder
are left-hand thread -- but at least for the right-hand nut -- chuck an

[ ... ]

The left arbor has a left-hand thread, the right arbor has a right-hand
thread. Both are M16x2. (There is no rotor lock, so it can be hard to
tighten and loosen the nuts.)

That is common with all bench grinders that I have used.

I don't know how common left-hand metric bolts are round these parts.

:-)

MSC and Grainger have none. Nor do I really want to buy 100 of these
nuts. At $20/100 times two, or $40, it's 2/3 what the grinder cost.

Understood.

As mentioned in another posting, it turns out that McMaster-Carr stocks
left-hand M16x2 nuts.

I also talked to Ryobi yesterday, and will call their local distributor.
The hope is that Ryobi has after two years already worked their way
through that batch of bad nuts. And I know one of the local service
centers - their people are able to use such products, and so should be
able to understand the problem. And to tell a good nut from a bad nut.


I could probably make you a stud for facing the left-hand nut
which you (presumably) already have -- using the Compact-5/CNC Emco
Maier lathe. But I will have to trust measuring over wires, because I
don't have a left hand thread sample to work from.

I'm not sure that the threaded stud to hold the nut to be faced will
work, as both faces are crooked, so the nut will tilt to one side when
tightened down to allow facing the free face.

How loose is the nut on the arbor?

You mean freedom to wobble when not tightened down? It's got to be a
few degrees, by eye, though I never measured it. These are not
precision instrument threads. But it's not loose enough for the nut to
rest flat when tightened.


I think that the only
solution is new nuts. I could make these nuts if I bought a set of
taps, but even that is going to cost a major fraction of the cost of the
grinder.

:-)

I'm going to call Roybi first. Maybe they have resolved their supply
problem. Or gotten lucky.

Hmm. I wonder what thread Jet grinders use?

A good question. I have an 8" Jet grinder -- and it has been an
excellent one so far. I guess that I could try measuring the thread on
the right-hand end with a thread checker or a thread pitch gauge. Even
if it is the same thread size and pitch, I don't know how different the
actual fit might be. :-)

I'm betting that if it's a standard M16x2 nut, it will fit. I don't
think Ryobi made the arbor threads wrong. I think they bought some bad
nuts.

If I replace the Ryobi, I'll look at Jet.

In retrospect, I should have boxed the Ryobi grinder up and dropped it
right in Ryobi's lap, to fix or replace or refund, back when this saga
began.

Joe Gwinn

On Mon, 14 Apr 2008 06:37:19 -0400, Ronald Thompson
wrote:

If the nut is drilled off center, will facing it do much good? It may
make the wheel straighter, but the nut will still be off center.

It would, but the mass imbalance of an offcenter nut would be trivial
compared to a wobbly wheel.

The first thing I would do is run the grinder without wheels and see if
it is smooth. If not, junk it unless you want to tear it apart. Next,
check the shafts for trueness with a dial indicator.
Then I'd add pieces one at a time to see what is vibrating.

Good plan!

In article ,
Ignoramus30238 wrote:

I would indeed junk the grinder.

There is too much at stake with the fast spinning wheel.

If the replacement nuts do solve the wobble problem, there should be no
more than the usual problems shared by all grinders. I've ordered new
wheel nuts from a local (to Boston) Ryobi service center, Panda
Electric. The people at this service center have clearly had things
apart, and understood the problem.

Joe Gwinn