EC

Electric Comet

22/12/2014 5:02 PM

random orbital sander wanting to go orbital

I don't use my dewalt sander that much but it's handy and useful. Using
it the other day and I held it off the workpiece for several seconds
while I was looking for dips, etc. The sander started spinning very fast
and I shut if off before starting to sand again.

I don't remember this ever happening so I guess something's either
broken or maybe it's dirty and instead of spinning randomly and orbital
it's only doing random or orbital. This make sense? Anyone seen this?
What's the cure? It's spinning so fast that if I were to continue
sanding without first shutting it off I'd be destroying the work
unless I was able to lay it perfectly flat on the surface.

When it's on the work it seems fine but without any resistance it
starts spinning very fast.



This topic has 13 replies

Ll

Leon

in reply to Electric Comet on 22/12/2014 5:02 PM

24/12/2014 11:25 AM

On 12/24/2014 11:23 AM, Electric Comet wrote:
> On Wed, 24 Dec 2014 11:19:38 -0600
> Leon <lcb11211@swbelldotnet> wrote:
>
> >
>> More than likely it would always spin fast if you simply let it spin
>
> No, it's back to normal again. Cleaning it out was the fix.
>
>> I remember when the brake feature was a selling feature on the newer
>> models. ;~)
>
> The brake's not needed if designed properly. It's all about the proper
> balance. I'd bet that an engineer figured that out at some point.
>
>
>

Gotcha, I misunderstood.

ME

Martin Eastburn

in reply to Electric Comet on 22/12/2014 5:02 PM

23/12/2014 8:47 PM

On 12/22/2014 11:57 PM, Electric Comet wrote:
> On Mon, 22 Dec 2014 22:27:03 -0500
> woodchucker <[email protected]> wrote:
>
>> if it's like the pc you wore out the O Ring belt.
>> get a new one, it controls the speed.
>
> Will take it apart and see what I need to buy. All the rubber on this
> dewalt has crumbled so I guess I'm not surprised. Well at least all
> the seals for the dust trap. The rubber on the switch cover's fine.
> Even the power cord is crumbling.
>
>
>
Sounds like extreme heat or gasoline or oil. Bet on the first two.

They dry out the 'softness' material in the plastic/rubber and leaves a
matrix.

wn

woodchucker

in reply to Electric Comet on 22/12/2014 5:02 PM

22/12/2014 10:27 PM

On 12/22/2014 8:02 PM, Electric Comet wrote:
> I don't use my dewalt sander that much but it's handy and useful. Using
> it the other day and I held it off the workpiece for several seconds
> while I was looking for dips, etc. The sander started spinning very fast
> and I shut if off before starting to sand again.
>
> I don't remember this ever happening so I guess something's either
> broken or maybe it's dirty and instead of spinning randomly and orbital
> it's only doing random or orbital. This make sense? Anyone seen this?
> What's the cure? It's spinning so fast that if I were to continue
> sanding without first shutting it off I'd be destroying the work
> unless I was able to lay it perfectly flat on the surface.
>
> When it's on the work it seems fine but without any resistance it
> starts spinning very fast.
>
>
>
if it's like the pc you wore out the O Ring belt.
get a new one, it controls the speed.

--
Jeff

Ab

"Artemus"

in reply to Electric Comet on 22/12/2014 5:02 PM

22/12/2014 6:31 PM


"Leon" <lcb11211@swbelldotnet> wrote in message
news:[email protected]...
> On 12/22/2014 7:02 PM, Electric Comet wrote:
>> I don't use my dewalt sander that much but it's handy and useful. Using
>> it the other day and I held it off the workpiece for several seconds
>> while I was looking for dips, etc. The sander started spinning very fast
>> and I shut if off before starting to sand again.
>>
>> I don't remember this ever happening so I guess something's either
>> broken or maybe it's dirty and instead of spinning randomly and orbital
>> it's only doing random or orbital. This make sense? Anyone seen this?
>> What's the cure? It's spinning so fast that if I were to continue
>> sanding without first shutting it off I'd be destroying the work
>> unless I was able to lay it perfectly flat on the surface.
>>
>> When it's on the work it seems fine but without any resistance it
>> starts spinning very fast.
>>
>>
>>
> Pretty common for an order ROS. My 25 year old PC ROS did this for day one.

My PC333VS did that when the silicone(?) friction band broke. A new band
solved the problem.
Art

EC

Electric Comet

in reply to Electric Comet on 22/12/2014 5:02 PM

22/12/2014 9:57 PM

On Mon, 22 Dec 2014 22:27:03 -0500
woodchucker <[email protected]> wrote:

> if it's like the pc you wore out the O Ring belt.
> get a new one, it controls the speed.

Will take it apart and see what I need to buy. All the rubber on this
dewalt has crumbled so I guess I'm not surprised. Well at least all
the seals for the dust trap. The rubber on the switch cover's fine.
Even the power cord is crumbling.


Bb

Brewster

in reply to Electric Comet on 22/12/2014 5:02 PM

23/12/2014 7:55 AM

On 12/22/14, 7:31 PM, Artemus wrote:
> "Leon" <lcb11211@swbelldotnet> wrote in message

> My PC333VS did that when the silicone(?) friction band broke. A new band
> solved the problem.
> Art
>
>

I have the exact same sander, same problem (broken belt).

The PC part costs several dollars, I just went to the local hardware
store and bought a generic black 'o' ring, costs $0.50 and has been
working perfectly for several years now.

-BR


--- news://freenews.netfront.net/ - complaints: [email protected] ---

EC

Electric Comet

in reply to Electric Comet on 22/12/2014 5:02 PM

23/12/2014 7:34 AM

On Tue, 23 Dec 2014 07:55:33 -0700
Brewster <[email protected]> wrote:

> I have the exact same sander, same problem (broken belt).
>
> The PC part costs several dollars, I just went to the local hardware
> store and bought a generic black 'o' ring, costs $0.50 and has been
> working perfectly for several years now.

Good call. I know the rings you mean. Once in a while I wander the aisles
just to get ideas and I remember looking at these o-rings. Now to
test my memory of what aisle that was.

EC

Electric Comet

in reply to Electric Comet on 22/12/2014 5:02 PM

23/12/2014 9:15 PM

On Mon, 22 Dec 2014 18:31:41 -0800
"Artemus" <[email protected]> wrote:

> My PC333VS did that when the silicone(?) friction band broke. A new
> band solved the problem.

Took the dewalt apart and no bands inside. I discovered that the problem
was due to build up of very fine dust in two places on the cast fan.
That gave the fan just the right balance to allow the pad to spin
at incredible rates. Like the perfect storm. A design flaw but not
one that would be easy to test or model but I wonder if they've
since fixed this.

With the pad removed the shaft would only spin so fast but with the
fan and pad attached it really got moving.

EC

Electric Comet

in reply to Electric Comet on 22/12/2014 5:02 PM

24/12/2014 9:23 AM

On Wed, 24 Dec 2014 11:19:38 -0600
Leon <lcb11211@swbelldotnet> wrote:

>
> More than likely it would always spin fast if you simply let it spin

No, it's back to normal again. Cleaning it out was the fix.

> I remember when the brake feature was a selling feature on the newer
> models. ;~)

The brake's not needed if designed properly. It's all about the proper
balance. I'd bet that an engineer figured that out at some point.


Bb

Brewster

in reply to Electric Comet on 22/12/2014 5:02 PM

25/12/2014 8:46 AM

On 12/24/14, 10:23 AM, Electric Comet wrote:
> On Wed, 24 Dec 2014 11:19:38 -0600
> Leon <lcb11211@swbelldotnet> wrote:
>
> >
>> More than likely it would always spin fast if you simply let it spin
>
> No, it's back to normal again. Cleaning it out was the fix.
>
>> I remember when the brake feature was a selling feature on the newer
>> models. ;~)
>
> The brake's not needed if designed properly. It's all about the proper
> balance. I'd bet that an engineer figured that out at some point.
>
>
>

After removing the pad on my PC (and seeing the broken belt), I thought
that there had to be a better way, this is a really lame way to control
rotation.

-BR


--- news://freenews.netfront.net/ - complaints: [email protected] ---

Ll

Leon

in reply to Electric Comet on 22/12/2014 5:02 PM

22/12/2014 7:13 PM

On 12/22/2014 7:02 PM, Electric Comet wrote:
> I don't use my dewalt sander that much but it's handy and useful. Using
> it the other day and I held it off the workpiece for several seconds
> while I was looking for dips, etc. The sander started spinning very fast
> and I shut if off before starting to sand again.
>
> I don't remember this ever happening so I guess something's either
> broken or maybe it's dirty and instead of spinning randomly and orbital
> it's only doing random or orbital. This make sense? Anyone seen this?
> What's the cure? It's spinning so fast that if I were to continue
> sanding without first shutting it off I'd be destroying the work
> unless I was able to lay it perfectly flat on the surface.
>
> When it's on the work it seems fine but without any resistance it
> starts spinning very fast.
>
>
>
Pretty common for an order ROS. My 25 year old PC ROS did this for day
one.

Ll

Leon

in reply to Electric Comet on 22/12/2014 5:02 PM

24/12/2014 11:19 AM

On 12/23/2014 11:15 PM, Electric Comet wrote:
> On Mon, 22 Dec 2014 18:31:41 -0800
> "Artemus" <[email protected]> wrote:
>
>> My PC333VS did that when the silicone(?) friction band broke. A new
>> band solved the problem.
>
> Took the dewalt apart and no bands inside. I discovered that the problem
> was due to build up of very fine dust in two places on the cast fan.
> That gave the fan just the right balance to allow the pad to spin
> at incredible rates. Like the perfect storm. A design flaw but not
> one that would be easy to test or model but I wonder if they've
> since fixed this.
>
> With the pad removed the shaft would only spin so fast but with the
> fan and pad attached it really got moving.
>
>


More than likely it would always spin fast if you simply let it spin
freely, especially if it is an older model similar to my old PC. FWIW
with the pad removed from my old PC the shaft would hardly spin at all
too.
I remember when the brake feature was a selling feature on the newer
models. ;~)

Ll

Leon

in reply to Electric Comet on 22/12/2014 5:02 PM

22/12/2014 9:56 PM

On 12/22/2014 8:31 PM, Artemus wrote:
> "Leon" <lcb11211@swbelldotnet> wrote in message
> news:[email protected]...
>> On 12/22/2014 7:02 PM, Electric Comet wrote:
>>> I don't use my dewalt sander that much but it's handy and useful. Using
>>> it the other day and I held it off the workpiece for several seconds
>>> while I was looking for dips, etc. The sander started spinning very fast
>>> and I shut if off before starting to sand again.
>>>
>>> I don't remember this ever happening so I guess something's either
>>> broken or maybe it's dirty and instead of spinning randomly and orbital
>>> it's only doing random or orbital. This make sense? Anyone seen this?
>>> What's the cure? It's spinning so fast that if I were to continue
>>> sanding without first shutting it off I'd be destroying the work
>>> unless I was able to lay it perfectly flat on the surface.
>>>
>>> When it's on the work it seems fine but without any resistance it
>>> starts spinning very fast.
>>>
>>>
>>>
>> Pretty common for an order ROS. My 25 year old PC ROS did this for day one.
>
> My PC333VS did that when the silicone(?) friction band broke. A new band
> solved the problem.
> Art
>
>
That is what the new ones do. ;~) I'm talking 1989. My Festool has a
similar brake but the old PC's had nothing at all.


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