shaping disk has wobble

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WillAndersonpipes
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shaping disk has wobble

Post by WillAndersonpipes »

hey guys my shaping disk has some pretty bad wobble to it It is a 7 inch gator grinding disk backer pad and I am just using 36 grit fiber sanding pads from lowes. the sanding pads are always curved when i get them and I am guessing this is what is causing the wobble. I think the fiber disks have actuallu bent my grinder backing pad out of shape. I was just wondering if you guys have the same problem and if a better brand of sanding pads or backing would help. thanks
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sandahlpipe
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Re: shaping disk has wobble

Post by sandahlpipe »

My sanding pads needed to be clamped to a flat surface for a day before I could use them. After a day or so of clamping to a flat surface, there was only a little bit of wobble, which has fixed itself with use. Also, to get them to work on the arbor of my motor, I machined a bushing to eliminate the wobble.
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WillAndersonpipes
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Re: shaping disk has wobble

Post by WillAndersonpipes »

Alright so there will always be a little bit of wobble?

watching videos and stuff of people shapping it always looks like there disks are spinning so true, but maybe its justbecause they are moving faster. I also have my sanding disk going at about 1750 rpm should i speed it up?
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sandahlpipe
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Re: shaping disk has wobble

Post by sandahlpipe »

My disc runs true after the clamping and a couple hours of use. 1750 is a fine speed to work with.
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WillAndersonpipes
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Re: shaping disk has wobble

Post by WillAndersonpipes »

Alright sounds good ill try that. What kind of disk are you using
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sandahlpipe
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Re: shaping disk has wobble

Post by sandahlpipe »

I'm using the Harbor Freight version. I wouldn't assume it's anything different than what you have except for the bushing I made.
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oklahoma red
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Re: shaping disk has wobble

Post by oklahoma red »

Usage will help flatten it. Use a chunk of hard wood and bear down on it against the disc. That will get it hot. Get some small clothes-pin type clamps and use them around the perimeter of the disc when you aren't using it. This will help keep it flat.
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andrew
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Re: shaping disk has wobble

Post by andrew »

I made my backing disk from aircraft aluminum. I just use a washer and spray adhesive to keep my sanding disk/wood chipper in place. Don't have to flatten the disk. 1/8" sheet doesn't even know the disk is adhered to it.
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oklahoma red
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Re: shaping disk has wobble

Post by oklahoma red »

andrew wrote:I made my backing disk from aircraft aluminum. I just use a washer and spray adhesive to keep my sanding disk/wood chipper in place. Don't have to flatten the disk. 1/8" sheet doesn't even know the disk is adhered to it.
Is your disc tapered or flat? Surgery on the sanding sheet is normally required if the disc is tapered.
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Re: shaping disk has wobble

Post by LatakiaLover »

For you carvers who really want to get after it, pick up Tim West's 7" high-speed-rated & balanced Briar Evaporator:

http://www.jhlowe.com/machine_parts.htm

It's counterintuitive, but the faster a disc spins the less resistance--"tugging"--there is of the work. At 5000+ rpm, it's like passing a block into a science fiction "disintegration field". Whatever enters simply disappears.

As for how to spin one that fast with your current motor, just rig a belt /pulley multiplier.
UFOs must be real. There's no other explanation for cats.
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Ratimus
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Re: shaping disk has wobble

Post by Ratimus »

LatakiaLover wrote:For you carvers who really want to get after it, pick up Tim West's 7" high-speed-rated & balanced Briar Evaporator:

http://www.jhlowe.com/machine_parts.htm

It's counterintuitive, but the faster a disc spins the less resistance--"tugging"--there is of the work. At 5000+ rpm, it's like passing a block into a science fiction "disintegration field". Whatever enters simply disappears.

As for how to spin one that fast with your current motor, just rig a belt /pulley multiplier.
+1

I use a 36 grit 7 inch wheel at my lathe's top speed (which is "only" 4000 rpm) and I find it to be smoother and much more precise than at lower speeds. Also, at that speed a slight wobble actually becomes a non issue and tends to all but magically disappear.
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caskwith
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Re: shaping disk has wobble

Post by caskwith »

For a many years now I have done all my shaping at 3000rpm, to being with just because it was convenient but now I much prefer it. You need a steady hand and practice though as at 40 grit the wood disappears fast!
Charl
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Re: shaping disk has wobble

Post by Charl »

I remember way back somebody (Rad, maybe?) said to wet it and then glue it on. Haven't tried it myself, but worth the try.
WillAndersonpipes
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Re: shaping disk has wobble

Post by WillAndersonpipes »

I actually just turned mine up to about 3000 rpms and the first time I touch the wood to it the sanding disk is pulled right up against the backing pad and the wobble is pretty much gone


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Ratimus
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Re: shaping disk has wobble

Post by Ratimus »

It's like the difference between whittling with a dull knife versus a sharp one. Counterintuitive maybe, but there's much more control, you don't have to press as hard, things are less likely to grab and slip etc. Glad you got it sorted.
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