Thread: new disc sander plate has raised pimples

G'Day "Dengue",
I would of thought any balance weights would have been squired on the inside of the heavy outer rim.....
It makes no sense to weight a disk in the middle like yours in the photo...
I'd personally be asking for a replacement as a flat surface plate should be that, flat....
Cheers, crowie

I wouldn't be happy with that. At all.

Personally, I'd mark their position on the outer edge of the disk for future reference, flatten the face and then spin it up - with all due precautions - to see if it throws it out of balance.

Hence the reference marks... if it did vibrate/wobble unacceptably, I'd use a small, sharp drill bit to remove a minute amount of material from the opposite edge of the disk until it came back into balance. (Having a tame metal-working friend to hand would be a bonus for this. )

Originally Posted by Dengue(in other thread)

Thanks for this advice, Hermit, but I am not sure what is causing the dimples, counterweights perhaps?

I find it extremely hard to believe that the manufacturer would add dimples to the previously machined flat surface as counterweights, (or for any other legitimate purpose). It totally defeats the purpose of creating a flat surface in the first place. They might as well leave it as a rough casting.

I'd either be grinding them off as Skew says, or as mentioned by Crowie, returning it and demanding a good replacement. They might have trouble finding one, though, unless they're prepared to tear the paper off the other sanders to find a good one.

As Skew also pointed out, there are other ways of balancing a disc - they definitely didn't need to add dimples to the face to do that.

It's still a puzzle though, as to how the dimples got there after machining???

Hi,
At a guess I would say, air bubbles near the surface, in the casting that expanded after machining and any QC, due to changes in atmospheric pressure during it's journey from wherever it was thrown together.
Regards

Originally Posted by A Duke

Hi,
At a guess I would say, air bubbles near the surface, in the casting that expanded after machining and any QC, due to changes in atmospheric pressure during it's journey from wherever it was thrown together.
Regards

I was just thinking along similar lines myself. Grinding off the dimples might reveal bubbles. I think I'd be returning it without even attempting to grind them off.

Edit: Looking at the close-ups of the dimples, they do look like bubbles that have expanded. There are even a couple of others visible that didn't expand much. The dimples have machine-marks on the surface, too, so weren't added after machining, either.

Originally Posted by Hermit

I was just thinking along similar lines myself. Grinding off the dimples might reveal bubbles. I think I'd be returning it without even attempting to grind them off.

Edit: Looking at the close-ups of the dimples, they do look like bubbles that have expanded. There are even a couple of others visible that didn't expand much. The dimples have machine-marks on the surface, too, so weren't added after machining, either.

Hi,
Personally I would grind them off and fill the poxy holes with epoxy then smooth them over.
Regards

Take it back and let them deal with it. It's not your job to fix someone else's problems, especially if you've paid good money for it.

EDIT: If the supplier has said there's no guarantee that the replacement won't have the same problem, it's tough s*%# for them. They legally have to give you a refund or keep replacing it until they get it right.

"....Chinese manufacturer"

That's the problem, right there. The bigger problem is that it's tough to get anything else with some machines.

Send it back (hopefully at their cost if it was freighted to you) - not for a replacement - for a refund, and then try another "brand" hoping that it doesn't come out of the same factory in "Disc Sander Street".

Like most others on here I've purchased cheaper (invariably of Chinese or Indian origin) machines and tools only to find some nasty little surprises down the track. From my point of view if a machine or tool needs a small modification or 'fix' to make it work properly then I just do it. It can sometimes save a lot of aggravation and time than having it replaced under warranty. At the end of the day I'm happy if my tools or machines do what I want them to do.

I'm not saying this is right or acceptable but sometimes when we take the risk of buying cheaper you just have to suck it up if the quality is less than we expected (or hoped) for.

So after that little ramble..... if it was me I would grind back the pimples until the face was flat then try it and see what happens.

Regards
Twosheds

I feel your pain and frustration. Or do I.
I ordered a disc sander for work thru our friendly rep and specified a cast iron disc and table.
When delivered it had an aluminium table so I refused to accept it.
That was just too hard for the rep so I sourced one from the WA mob and the cost delivered to Sydney was the same as for the p o s the local clowns stocked.
This rep is freelance and saved us a lot of chasing around but was always selling what gave him the biggest margin.
A good conservative and staunch supporter of you know who in the red speedos.
We needed a new heavy duty linisher and a cut off saw and guess what, I was able to buy the best in the world.
A Linishall and a Brobo Waldown both made here in Oz.
The neighbouring department decided to buy a linisher also and guess what the clown came up with? Chinese crap and this at a Uni where within reason $ were not an issue.
All we are doing is buying our own demise I'm now retired but find people's attitude amazingly shortsighted.
Some people will pay for quality re Lee Valley etc. We are also up to about 30 of the Ewheels and will be shipping a few to the US for SEMA later.
Do what a local engineering company did with 6 Chinese bench drills after a years work,they put them in the cupola for scrap. In the meantime Sterling? who had taken over production of Richardson had gone broke.
The suppliers of this Chinese crap don't have a clue, the man in white shoes at carbcrap only changed to the slower speed dic after I commented and the wobble on the biscuit jointer wasn't a problem. I was just too fussy, it's only woodwork.
I guess if you are happy with Velcro backed paper the little bumps won't really make much difference.
Enjoying the weather here in Canada it's finally as warm here as in Oz.
H.

Not acceptable supplier should replace, however if your are going to use a velcro system you won't notice it

check the back of the disc to see if they match up with some heated spots, if the machine is only new take it back and see as they have got a right to repair as its the law. Or as china said if you go with a Velcro attached disc they should be covered under the two layers of backing & sanding disc
regards Michael

Looks like its been drilled from behind as part of possibly balancing the disk - pushing the "pimple" out. they are nicely lined up and doesn't seem like random defect bubbles.

Get a file, flatten it off, fill any holes with epoxy( and flatten again) or just put the Velcro backing straight on it and see how it goes.