My buffers, grinders, brushes like to dance on my concrete garage floor. A few of them have been anchored into the floor. The rest of them need to be repositioned frequently so I can't anchor them.
What's your favorite method of keeping rotating machinery for dancing across the floor.
I've tried scrap carpet, rubber matting, etc.
Do you have a favorite method??
Are they sitting on casters or the raw stands? If they are on casters, cut donuts out of plywood scraps to suspend the casters slightly above the floor. I prefer to attach them to a strong workbench or workmate.
My small grinder I've got mounted on an old truck brake drum for dampening and then that sits on a piece of carpet which sits on my workbench.
Adding mass is a good way to suck up a lot of the vibration. I had a washing machine that had a big chunk of concrete bolted to the floating part. Very nice. The more mass the better the dampening will be, but it has to be firmly affixed to the part that generates the motion.
They are balanced but the cast iron bases on a concrete floor just don't provide enough coefficient of friction to make them stay put.
I need an interface material that grips concrete and cast iron.
The machinery is pretty good quality (ie mostly Baldor) but some of the pedestals are Harbor Freight crap. (i don't mind buying Baldor buffers and grinders but their pedestals seem too high priced for what you get).
I filled some of the pedestals with concrete to give them more mass. It helps but there's just not enough friction between cast iron and concrete when motors are spinning at 3600 rpm.
Interpose a sheet of rubber (cut up truck innertube?) between the pedestal and floor?
GWE
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I think you need a bigger footprint. I welded up a stand for my 2 HP
3450-RPM buffer with an H base that is 24" x 28". It doesn't dance at all and it's easy to move. Include diagonal braces from the extremities of the H footprint to somewhere on the column so it'll be an acceptably stiff structure.Underlying theory: the system must be balanced enough so it can't hop clear off the ground. Beyond that, a dynamically unbalanced system creates a rotating moment on the pedestal that can cause the base to dance with rotating single-point contact to the floor. With a big enough footprint and acceptable flexure in the pedestal and/or compliance in the points of contact, there will always be at least two contact points with the floor. When this condition exists, it can't dance no matter how good the tunes on the radio. Larger footprint means less motion at the work wheel for necessary compliance between points of contact and dynamically-unbalanced rotating mass if at least two points of contact are to be maintained.
A totally rigid structure supporting a dynamically unbalanced rotating mass on a totally-noncompliant floor would dance with single point contact and infinitesimal clearance elsewhere, regardless of the mass of the base. Real world, no structure is totally rigid and even a concrete floor has some compliance. My point here is to show that pouring concrete (or lead or depleted uranium) into the base isn't the only solution and perhaps not the best solution if mobility is an issue. The trick is to get the moments and compliances to where at least two points of contact are always maintained by gravity (rather than bolts) with acceptable motion at the work wheel. The compliance can come from rubber feet, carpeting, flexure in the structure, whatever works. Larger footprint means less motion at the wheel for given compliance.
Bottom line: bigger footprint works for me.
snipped-for-privacy@gmail.com wrote in news:1128997976.637346.31980 @g47g2000cwa.googlegroups.com:
A sufficiently sized piece of perforated sheet metal hinged to the base. Where upon you stand while working with the grinder/buffer, etc. The metal folds up against the base when you are not using it.
Anthony
Yep...I balance them.
Then the only thing I have moving around is my 8" Logan shaper..if I crank up the speeds
Ive got at least 3 grinders, and 3 belt sanders..and none of them wander around. Well..I do have one big assed grinder with a pair of 8" cheapie wire wheels on it that does tend to move in slow circles..so I bolted it down to the bench. But one of the shafts is bent by about .008
Gunner
Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry
Carpet works great for my compressor. That was Gunner's suggestion.
iI've had some trouble with one grinder walking around. After a lot of experimentation, I finally just pushed it up against the wall so that it can't turn, stretched a bungie around the pedestal at the base and hooked it to screw eyes in the wall. Lets me move it when necessary, but keeps it in place otherwise. You could anchor a wooden strip to the floor and do the same if you can't put it against the wall.
Set them in a box of sand.
Yea, but doesn't your packed dirt shop floor have a higher coefficient of friction than smooth concrete?
Pete C.
On 10 Oct 2005 20:18:47 -0700, with neither quill nor qualm, snipped-for-privacy@gmail.com quickly quoth:
Weld a stand-on plate to the bottom and put anti-skid matting under it. Step on the plate to do the work, holding the whole machine steadier.
My deluxe HF stand has 3 bolt-holes and I could mount it to a piece of plywood if I were so inclined. That could be anti-skidded, too.
Yeah, mass always helps dampen vibrations. Add anti-skid shop matting or some of the thicker shelf liner. (Don't get caught sneaking it out of the kitchen.)
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One problem I have encountered is that gyroscopic precession causes the buffer to slowly turn. Even though it's on 3 rubber feet the force acting on the buffer is pretty strong so the whole thing spins slowly. A fix for this, and your problem too, is to bolt the grinder pedestal to a piece of plywood that's as wide as the pedestal base but 2 or 3 times longer. Then you stand on the plywood when you use the grinder. This prevents twisting motion and lets youput more force against the wheel. ERS
McMaster-Carr sells neoprene sheets in a range of hardness from "squisshy" to very hard. One of the medium soft should work. They also sell sample packs to try before you invest in large sheets. I've used these before to design clamps. Good luck.
dennis in nca
That's very nice. I will soon add a second idler to my phase converter (and will probably redo the frame with welded steel angle), and this seems like a good way to add vibration isolation.
For my generator, I used car tires.
It would indeed..if the grinders etc were sitting on the dirt, rather than on bench tops.
Gunner
Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry
Since much of the thread referred to the typical grinder stands and your post didn't say otherwise except for one grinder I assumed some were on such stands. My bad.
Pete C.
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