Grinding Assembled Parts

I don't think there's any argument, just fellas weighing in with their viewponts. I would agree with AD if that part were shaped as depicted in his illustration with equal diameters at both ends. And he did give accurate caveats of things that might cause problems.

Nope, no argument or hard feelings from me either. As posted above, just discussion of methods. Doubtful I'm revealing anything new to the usual suspects (Buck, Eric) but thought a couple of the newer machinists on the board might find it useful. As also mentioned, clamping on only ONE narrow diameter is not enough contact surface to constitute a solid setup. Squeezing a component in a vise could be asking for a marred surface or an egg-shaped diameter.

Perhaps being in semi-retirement has generated a greater sense of urgency to pass on what little I know to those entering the trades, handing off the torch. Maybe I should go sit down in the back row for a while.

AD Design said:

Nope, no argument or hard feelings from me either. As posted above, just discussion of methods. Doubtful I'm revealing anything new to the usual suspects (Buck, Eric) but thought a couple of the newer machinists on the board might find it useful. As also mentioned, clamping on only ONE narrow diameter is not enough contact surface to constitute a solid setup. Squeezing a component in a vise could be asking for a marred surface or an egg-shaped diameter.

Perhaps being in semi-retirement has generated a greater sense of urgency to pass on what little I know to those entering the trades, handing off the torch. Maybe I should go sit down in the back row for a while.

Click to expand...

Nah, you're good. Keep up the good work. My personal thoughts are that all shared ideas here are good. If nothing else they give something to think about or keep in the back pocket for another job. It's obvious you have good knowledge on the subject, don't stop sharing it. Your thoughts about helping the newer guys are right on the money as far as I'm concerned, and that's a noble goal. I try to do the same when I can. Buck is master level at that.

More on why Tormach should stay away from the subject of grinding.

The old wheel ring is Ok, He should have demonstrated a truly cracked wheel.

Not an arbor but is a wheel mount or adaptor, and some call it a hub.

Not bladders but are blotters
.
The wrong side of the flange nut was set facing the wheel.

No mount-up line was added to the wheel at mounting.

No mention of where to set the diamond or to turn the diamond to a fresh facet when dull.

The diamond holder is straight up, so to flat/round/dull the diamond.

Diamond dresser set straight out from the part ( 5:12), so chancing to wheel crash into the part.

Suggest “we are only going to balance for 5,000rpm”, the machine spec is 3450 and likely the wheel is rated for the same. One should know the grinder machine spindle and wheel RPM(OSHA)

No mention of “look at wheel RPM spec on wheel marking label” (OSHA).

Inspect wheel mount for damage not mentioned. (OSHA).

Both the flange and spindle nut were not properly tightened.

“Just wiggle and the wheel comes off” (because it was not properly tightened, likely to self tighten with heavey grinding and so make the wheel have a chatter grind finish, done often this could ruin the spindle nose taper.)

Warm up spindle 10-15 minutes, not needed with a bearing spindle. (Ok to warm up the travels if doing very fussy work.)

“Re dress, As soon as you turn off the spindle the dress is useless.” How could one grind with a wheel so loose, actual grinding and the fire-up has more torque than the slowing down.

Note: at 12:53 a very poor part surface finish from a light grind with an 80gt wheel. likely a rounded diamond or the wheel turned a tad on the wheel mount at the spindle start-up...or just that this light machine is not smooth/solid enough to get the finish an 80gt should produce,

Plus a few more things.

Blotters are called that because they Soak-up the high point of an abrasive grit, that would otherwise push inward and likely crack the wheel.

Helping to hold the wheel and protecting the wheel mount faces are also important, but secondary to absorbing the high grit facets.
Blotters should be thick enough to absorb such grits, bought ones or made from cereal box stock, never paper thin.

See, told ya'.