I have a used Darex M4 drill grinder and the wheel flange assembly is a
little odd, at least in my limited experience.

The clamping mechanism on the outside of each wheel consists of a dished
flange which slips over the threaded motor arbor, a short collar, a large
slotted washer, another semi-dished washer, and the arbor nut. The collar
nests inside the the two washers and the nut forces that little assembly
against the wheel flange. The manual available at the Darex web site shows
a different clamping mechanism.

It looks like the slotted washer is intended to be adjusted to balance the
wheel - does that make sense? If so, is there a procedure to use for
balancing the wheel or is it just trial and error?

If anybody has a copy of a manual that depicts this assembly and/or
instructions on how to adjust it, I'd love to get a copy of those pages.

If Harold reads this, I should note that both wheels have blotters on each
side.

Mike

Mike Henry wrote:
I have a used Darex M4 drill grinder and the wheel flange assembly is a
little odd, at least in my limited experience.

The clamping mechanism on the outside of each wheel consists of a dished
flange which slips over the threaded motor arbor, a short collar, a large
slotted washer, another semi-dished washer, and the arbor nut. The collar
nests inside the the two washers and the nut forces that little assembly
against the wheel flange. The manual available at the Darex web site shows
a different clamping mechanism.

It looks like the slotted washer is intended to be adjusted to balance the
wheel - does that make sense? If so, is there a procedure to use for
balancing the wheel or is it just trial and error?

If anybody has a copy of a manual that depicts this assembly and/or
instructions on how to adjust it, I'd love to get a copy of those pages.

Easy. http://www.darex.com/support/manuals...MANUAL2001.PDF, p. 11

Grant

"Grant Erwin" wrote in message
...
Mike Henry wrote:
I have a used Darex M4 drill grinder and the wheel flange assembly is a
little odd, at least in my limited experience.

The clamping mechanism on the outside of each wheel consists of a dished
flange which slips over the threaded motor arbor, a short collar, a large
slotted washer, another semi-dished washer, and the arbor nut. The
collar nests inside the the two washers and the nut forces that little
assembly against the wheel flange. The manual available at the Darex web
site shows a different clamping mechanism.

It looks like the slotted washer is intended to be adjusted to balance
the wheel - does that make sense? If so, is there a procedure to use for
balancing the wheel or is it just trial and error?

If anybody has a copy of a manual that depicts this assembly and/or
instructions on how to adjust it, I'd love to get a copy of those pages.

Easy. http://www.darex.com/support/manuals...MANUAL2001.PDF, p. 11

Grant

Thanks Grant, but that manual shows a different flange assembly than the one
on this Darex. Presumably that sates my grinder to some time before 2001.

Mike

Mike Henry wrote:
snip

Thanks Grant, but that manual shows a different flange assembly than the one
on this Darex. Presumably that sates my grinder to some time before 2001.

I bet the instructions are still current, though. Summarizing:

remove screws, outer and balancing washers and old wheel
install new wheel, must have light side marked
install balancing and any outer washers, any screws should be firm not
tight, move balance washer about 1/16" from center towards light mark then
tighten screws
mark where balance washer is located w.r.t. light mark
assemble, test, if vibration
loosen slightly, tap balance washer, tighten, reassemble .. repeat as needed

Or you can simply leave the balancing washer off and just true your wheels,
maybe they'll run smoothly that way.

It is certainly possible to make a wheel balancing setup. I did one once for an
eccentric (small armature) which I wrote up as:

I was recently able to largely balance a motor which had
a bad static imbalance. I used a knife-edge setup as follows:

I started by leveling my surface plate carefully. If you
don't have a surface plate, you can use the top of a table
saw or some other flat surface you can level. I bought a
piece of 1/8 by 1" O1 ground flat stock and machined a 45
degree bevel on one end. (I did this with a 12" disc sander
with a tilting table - a milling machine may be much faster.)
I cut the 18" beveled stock in half, giving me 2 roughly 9"
pieces. I used 4 3/8-16 screws and washers as rough "clamps"
on the sides of 1-2-3 blocks. I then clamped a block to the
end of each knife. I lined up the knives so they were flat
and parallel and level.

I then put the motor's armature (aka "rotor") on the knives.
I saw that the two ends of the shafts were of different
diameters. On one such motor there was a narrow area close
to the rotor body where there were equal-sized shaft diameters.
I used those. On another such motor I had to turn a suitable
bushing in the lathe. Anyway, once on the knives the rotor
with the static imbalance immediately tumbled to its position
with the heavy side down. I drilled round the rim on both
ends of the rotor to bring it as closely back into balance
as I could, frequently checking the balance on the knives.
Reassembled, that particular motor ran far more smoothly.


One more note on home balancing - it is possible to remove
weight from the heavy side by drilling as just described. In
a couple of cases I have not been able to remove enough
weight this way and I have found a method that worked well
for me, to add weight to the light side. Start with an old
wheel weight. Then, on the light side, make a cone-shaped
indentation with the drill (i.e. start a hole but don't
penetrate through). Then take the whole thing to your
kitchen, and pick your rattiest kitchen spoon. Cut off a
chunk of the wheel weight about 1/4" cubic, and melt it
in the old spoon, then pour it into the hole you drilled.
It will not bond, but it will sit there and bead up on
top and will exactly fit the indentation. Then, after
everything is cool, put a drop of superglue into the
indentation and then put the just-cast weight in, just
as you poured it. Hold it there for 30 seconds or so. This
glue worked just fine for me. I was able to make the light
side just slightly heavy in this manner, and then hit the
raised part of the weights with the belt sander a "kiss"
at a time until the part came balanced on the knives.

"Grant Erwin" wrote in message
...
Mike Henry wrote:
snip

Thanks Grant, but that manual shows a different flange assembly than the
one on this Darex. Presumably that sates my grinder to some time before
2001.

I bet the instructions are still current, though. Summarizing:

remove screws, outer and balancing washers and old wheel
install new wheel, must have light side marked
install balancing and any outer washers, any screws should be firm not
tight, move balance washer about 1/16" from center towards light mark then
tighten screws
mark where balance washer is located w.r.t. light mark
assemble, test, if vibration
loosen slightly, tap balance washer, tighten, reassemble .. repeat as
needed

Or you can simply leave the balancing washer off and just true your
wheels, maybe they'll run smoothly that way.

Thanks - the directions on page 9 seem appropriate for the setup on this
grinder and it looks like it is largely a trial and error proposition.
That's fine - just didn't want to miss out on a trick that wasn't obvious.

For fine tuning, I suppose that the wheels could be mounted to a shop-made
mandrel and balanced as you suggest below with balancing washer position
marked so as to duplicate them on the grinder itself. That may make a lot
of sense since there is a wheel on both ends of the arbor/motor shaft and
trying to chase balance on both of them simultaneously could be tedious.
For now, though, it seems to be running pretty well with just an eyeball
adjustment on the washers. There's a small chip out of the periphery of one
wheel and while the wheel seems to be otherwie solid, it should probably be
replaced anyway.

Mike


It is certainly possible to make a wheel balancing setup. I did one once
for an eccentric (small armature) which I wrote up as:

I was recently able to largely balance a motor which had
a bad static imbalance. I used a knife-edge setup as follows:

I started by leveling my surface plate carefully. If you
don't have a surface plate, you can use the top of a table
saw or some other flat surface you can level. I bought a
piece of 1/8 by 1" O1 ground flat stock and machined a 45
degree bevel on one end. (I did this with a 12" disc sander
with a tilting table - a milling machine may be much faster.)
I cut the 18" beveled stock in half, giving me 2 roughly 9"
pieces. I used 4 3/8-16 screws and washers as rough "clamps"
on the sides of 1-2-3 blocks. I then clamped a block to the
end of each knife. I lined up the knives so they were flat
and parallel and level.

I then put the motor's armature (aka "rotor") on the knives.
I saw that the two ends of the shafts were of different
diameters. On one such motor there was a narrow area close
to the rotor body where there were equal-sized shaft diameters.
I used those. On another such motor I had to turn a suitable
bushing in the lathe. Anyway, once on the knives the rotor
with the static imbalance immediately tumbled to its position
with the heavy side down. I drilled round the rim on both
ends of the rotor to bring it as closely back into balance
as I could, frequently checking the balance on the knives.
Reassembled, that particular motor ran far more smoothly.


One more note on home balancing - it is possible to remove
weight from the heavy side by drilling as just described. In
a couple of cases I have not been able to remove enough
weight this way and I have found a method that worked well
for me, to add weight to the light side. Start with an old
wheel weight. Then, on the light side, make a cone-shaped
indentation with the drill (i.e. start a hole but don't
penetrate through). Then take the whole thing to your
kitchen, and pick your rattiest kitchen spoon. Cut off a
chunk of the wheel weight about 1/4" cubic, and melt it
in the old spoon, then pour it into the hole you drilled.
It will not bond, but it will sit there and bead up on
top and will exactly fit the indentation. Then, after
everything is cool, put a drop of superglue into the
indentation and then put the just-cast weight in, just
as you poured it. Hold it there for 30 seconds or so. This
glue worked just fine for me. I was able to make the light
side just slightly heavy in this manner, and then hit the
raised part of the weights with the belt sander a "kiss"
at a time until the part came balanced on the knives.

"Mike Henry" wrote in message
...
I have a used Darex M4 drill grinder and the wheel flange assembly is a
little odd, at least in my limited experience.

The clamping mechanism on the outside of each wheel consists of a dished
flange which slips over the threaded motor arbor, a short collar, a large
slotted washer, another semi-dished washer, and the arbor nut. The collar
nests inside the the two washers and the nut forces that little assembly
against the wheel flange. The manual available at the Darex web site
shows
a different clamping mechanism.

It looks like the slotted washer is intended to be adjusted to balance the
wheel - does that make sense? If so, is there a procedure to use for
balancing the wheel or is it just trial and error?

If anybody has a copy of a manual that depicts this assembly and/or
instructions on how to adjust it, I'd love to get a copy of those pages.

It will be on its way as an attachment shortly, Mike.


If Harold reads this, I should note that both wheels have blotters on each
side.

Chuckle!

Harold

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

"Mike Henry" wrote in message
...
snip
It looks like the slotted washer is intended to be adjusted to balance
the
wheel - does that make sense? If so, is there a procedure to use for
balancing the wheel or is it just trial and error?

If anybody has a copy of a manual that depicts this assembly and/or
instructions on how to adjust it, I'd love to get a copy of those pages.

It will be on its way as an attachment shortly, Mike.

Got it - thanks.

If Harold reads this, I should note that both wheels have blotters on
each
side.

Chuckle!

Thought you might get a kick out of that. Checking for them is automatic
now.