|
Posted by Joseph Gwinn on April 13, 2008, 11:04 pm
Please log in for more thread options
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
|
|
Posted by Bill Noble on April 14, 2008, 12:21 am
Please log in for more thread options
>
> 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 **
|
|
Posted by Bill Noble on April 14, 2008, 1:27 am
Please log in for more thread options
>
>
> 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 **
|
|
Posted by Joseph Gwinn on April 14, 2008, 9:10 am
Please log in for more thread options
> >
> >
> > 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
|
|
Posted by DoN. Nichols on April 14, 2008, 1:10 am
Please log in for more thread options > 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.
--
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
|
| Similar Threads | Posted | | Re: Ryobi BGH827 8" bench grinder vibration | May 17, 2008, 10:40 am |
| Ryobi BGH827 8" bench grinder vibration - postscript | May 25, 2008, 8:08 pm |
| Good lathe bench top material to damp vibration? | January 15, 2007, 4:09 am |
| Surface Grinder Wheel Vibration | January 25, 2008, 2:47 pm |
| Bench Grinder | December 25, 2007, 8:55 pm |
| Bench grinder recommendation | February 14, 2008, 5:05 pm |
| 6" cut-off wheel in a bench grinder | May 27, 2008, 1:31 am |
| Rewinding a Bench Grinder Motor | February 9, 2007, 12:16 am |
| bench grinder wheel replacement? | April 23, 2006, 6:10 pm |
| Ryobi SC-160 Scroll Saw Speed Control? | June 11, 2007, 4:14 pm |
|
|
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML Sitemap
> 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.