Grinder Vibration Question

[Paul Atkins]

Maybe we need a thread on grinder speed - Thanks Gordon for the Oneway link - I'm not sure why spm for grinding is critical. My grinders are belt driven with stepped pulleys so I can change speeds -hardly ever do- maybe I'll crank em up a bit. I grind all my tools on the two grinders including Japanese chisels, plane blades , jointer blades and metal lathe bits so I think slower keeps them a bit cooler and a little less frantic. The carbon steel tools need a bit more care than HSS. I turn 1/2 thick aluminum flanges for the wheels and honing pad to keep them flat which is better than the stamped ones. Another 2 cents anyway.

[John Ponder]

Paul,
I think you are on to something with your ½ inch thick aluminum pads. Most of the mid-priced grinders I have seen all use stamped steel washers to retain the wheels. It does not matter how straight the wheels are if the retainers are warped. Please give us more details about your aluminum spacers, you may have a new product to market here.
Thanks,
John

[Paul Atkins]

Here are 2 different ones - one is 3/8" the other 1/2" thick. Pretty simple -reamed to fit shaft too.

[John Ponder]

Paul,
Those look great and should cure any problems with wobbling grinder wheels. I wish someone would market them. Thanks again,
John

[Randy Klein]

I wish someone would market them.

IIRC, that is the main benefit of the Oneway balancing system - machined washers.

[John Ponder]

I’ve never seen the Oneway system in person, but I’ll order one today and see if it helps. Although I do wish I had the ability to turn some like Paul’s.
John

[Gordon Seto]

You may want to consider replacing the flimsy stamped washer with the extra thick precision washer with low parallelism (page 742)

http://www.use-enco.com/CGI/INPDFF?P...PARTPG=INLMK32

[John Ponder]

Those look good but I assumed that the O.D. should be approximately the same as the stamped steel retainers. Any thoughts?
John

[Gordon Seto]

The steel washers that came with the Oneway balancing system are about 1¼" OD. But they are against the machined aluminum balancing hub.

The picture shows the difference between flanges of the $80 WC special and the $200 heavy duty Delta slow speed grinder.
It clearly shows that only portion of the WC flange was making contact with the wheel.

[John Ponder]

Maybe I misunderstood, did you mean use the small washers WITH the balancer kit? I understand you don’t use the stock retainer washers with the kit. Those retainer washers from the HD Delta look good, are they straighter than the ones on the WC?
John

[Richard Madison]

Thought I had an idea for a moment there, based on Paul's post, but I was wrong. Remember saw blade "stabilizers"? But they are for 5/8" arbor, and IIRC most grinder arbors are 1/2". Never mind.

[Gordon Seto]

Maybe I misunderstood, did you mean use the small washers WITH the balancer kit? I understand you don’t use the stock retainer washers with the kit. Those retainer washers from the HD Delta look good, are they straighter than the ones on the WC?
John

See Instruction #10
http://www.oneway.ca/pdf/balance_kit.pdf

The retainer washers on the HD Delta looks like they were machined (circular milling marks on both sides), they are flat. Those from the WC were stamped from heavy sheet metal. From the uneven scratch marks, it was obvious that the washer did not have even contact with the grinding wheel.

This is from the 100 pounds 8" Delta grinder.
The Delta 8" variable speed grinder is only 48 pounds.
The Delta 8" single speed grinder is 24 pounds.

[John Ponder]

OK, now I understand. Hopefully the balancer kit will arrive this week. Thanks for all the help and information.
John

[Jerry Allen]

I got a WC 8". One of the steps on the motor shaft where the inner flange washer rides had not been completed at the factory. WC replaced it immediately.
The step that the inner washer rides on is critical. If the step is not perfectly flat and pependicular to the shaft axis, you will have problems. A small error (or even a chip of wood or dirt) will magnify the error at the edge of the wheel. The washers are a lot larger, so less magnification, but warpage or a sloppy center hole can really throw it off. The washer can be flattened using aggresive grit and a sheet of plate glass if the error is not too great, or it can be shimmed a bit with pieces of paper placed stategically at the periphery of the washer.

[Tim Thomas]

My boss has an iPhone and he recently downloaded a seismograph application for it. You can put the iPhone down on a flat surface (like a table) and then tap around it and it will measure the vibrations and produce a graph. When he showed it to me I thought "That's neat, but what the heck would you ever NEED it for?!?!". Now I know. You could use it to measure the vibrations produced by your power tools. We could use these objective measurements to solve long-standing arguments about the virtues of link belts in reducing vibration, prove the value of dressing grinder wheels, and all other manner of machine vibration connundrums.

Of course, this will only work if you have an iPhone, and I don't, so I'll have to leave it to some other woodworker to see if my crackpot idea actually has any merit...

(Although, I do have several friends with iPhones. Maybe they would be willing to help me experiment. But convincing them to place delicate and expensive electronics on top of my woodworking equipment might be a hard sell. Hmm....)

** edit **
link to iPhone app I am talking about: http://coneri.se/iphone