In article ,
"Harold and Susan Vordos" wrote:

"Joseph Gwinn" wrote in message
...
snip-----

I understand the split-point geometry well enough,
but first I need some practice hand-grinding, so I'll do plain points at
first.

Certainly not a bad idea. Hand sharpening is a bit of an art and requires
considerable practice. No sense rushing things.

Following another poster's suggestion, I hand flattened the mating
surfaces by wet sanding on a granite surface plate, and broke the sharp
corners with a hand file. Stones still wobbled, but one possible cause
eliminated. The irregularities should also be much reduced, if the two
surfaces of the flanges are parallel.

The term "stone" is not generally applied to grinding *wheels* in the
industry.

Like whetstone? (Picture old guy sharpening a knife on an old sandstone
wet wheel.) Actually, I did wonder what the correct term was these days.


Do you have any machining capabilities? I'd suggest to you that making new
flanges would be in order. Having read below that your flanges are
pressed steel, I can't help but think that they are in large part your
problem. The very idea that you moved the wheel about and got it to run
better indicates to me that the
wheel(s) are also not great. That doesn't mean they aren't serviceable,
assuming you can get flanges that run true. You can always dress the sides
of a wheel to improve how it runs. Fact is, that's fairly common.

I don't yet have the equipment to make my own flanges. Does anyone know
of a supplier? I have to believe that people need flanges. Perhaps
available as a repair part?


The problem of wheels not being parallel is not uncommon, which I may have
mentioned. Norton has a terrific reputation in the abrasive world, and
still manages to turn out the occasional wheel that isn't parallel.

I'll look into Norton, after the flange problem is solved.


The stones are 1" wide and 8" (not 6") in diameter, on a 5/8" arbor, are
gray, and claim to be made by Ryobi.

The only problem I see is that the abrasive is likely not well suited to
grinding HSS. You will be somewhat limited as to the wheels that are
available to you, however. The greatest selection tends to come from
wheels that have a 1-1/4" arbor. Such wheels are used on cutter grinders and
small surface grinders.

One can get expanders; I've seen them in the catalogs, but none that
would bridge 5/8 to 1-1/4, if I recall. Perhaps this would also solve
the flange problem. Any suggestions of possible sources?

What kinds of wheel are best for HSS? (I don't plan to use much
carbide, at least not at first.)


Don't over tighten. It's not necessary.

Define "over-tighten", please. The spindle nuts are now looser than
they were in the as-received machine, but still I'd like to know the
limit to be avoided.

Sort of hard to describe. If you hold the wheel by hand, and tighten the
nut with a wrench, when the wrench overcomes your ability to hold the wheel
from turning, you have it tight enough to serve without problems. I
tighten wheels on my grinder by that method and don't have any problems with
the wheels coming loose, even when running in reverse. If you do heavy
grinding, such as might be done in welding, that may not be tight enough.

As luck would have it, that's exactly what I did, once I got the nuts
off (they were far tighter).

The left-handed nut wouldn't turn freely by hand on the thread until I
fitted it with a little valve-grinding compound and elbow grease.


Using a dial indicator, I measured the wobble on one flange: 0.008" at
1.25" radius. This would translate to (4/1.25)(0.008)= 0.0256" at the
outer edge of the stone. This is approximately what I see by eye.

That clearly sucks. Flanges should run true, or be free to float, so they
*can't* hold a wheel at an angle. The shoulder on the arbor should be
true. In turn, it should hold the flange true. Anything less isn't a good
thing.

I thought as much. So, the flanges are problem one.


(Don't want to grind the dial indicator probe tip, so didn't indicate
against the stone.)

Good decision. No need to-----the flanges tell you everything you need to
know. Until they run true, nothing else matters.

Later, I did an approximate indication on the stone, carefully lifting
the tip before moving the stone. It was a bit fiddly and inaccurate
(because indicator assembly isn't bolted to anything), but the wobble is
in fact the ~0.025" at 4" radius expected from extrapolation of the
flange wobble.

All roads appear to lead to those flanges.


Another poster suggested ditching the OEM stones, which are made by
Ryobi. Is this likely to solve the problem, or at least help?

Assuming you end up with wheels that have a similar discrepancy, and you
have the good fortune to align them such that the errors cancel one another,
yes, it could help, but the best fix is to get the flanges running true.
Once you do that, you can readily correct the wheels by dressing, should
they need correcting.

If all else fails, and you're "stuck" with the flanges that don't run true,
you might try tapping them gently with a soft hammer until you get them to
run true. If they are a snug fit on the arbor, as you suggest, that
could improve performance.

What I can do is to manually hand-grind the flange using wet sandpaper
on the surface plate, or hand-scrape the flange, but this is likely to
be a slow process, like hand-grinding a telescope mirror.

I have to believe that machined flanges can be bought.


Beyond that, the way I see it, new flanges are
in order.

Another thing I may try is to call Ryobi and complain. But I don't know
that this will help, as all they are likely to do is give me some more
of the same kind of stamped metal flanges in the irrational hope that
they will somehow be better.

Joe Gwinn